Journal articles on the topic 'Axial flow impeller blades'
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1
Fořt, Ivan, Pavel Seichter, Luboš Pešl, František Rieger, and Tomáš Jirout. "BLENDING CHARACTERISTICS OF HIGH-SPEED ROTARY IMPELLERS." Chemical and Process Engineering 34, no. 4 (December 1, 2013): 427–34. http://dx.doi.org/10.2478/cpe-2013-0035.
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Abstract This paper presents a comparison of the blending efficiency of eight high-speed rotary impellers in a fully baffled cylindrical vessel under the turbulent flow regime of agitated charge. Results of carried out experiments (blending time and impeller power input) confirm that the down pumping axial flow impellers exhibit better blending efficiency than the high-speed rotary impellers with prevailing radial discharge flow. It follows from presented results that, especially for large scale industrial realisations, the axial flow impellers with profiled blades bring maximum energy savings in comparison with the standard impellers with inclined flat blades (pitched blade impellers).
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Mandryka, A., A. P. Majid, Оleksandr Ratushnyi, Oleksandr Kulikov, and D. Sukhostavets. "Ways for Improvement of Reverse Axial Pumps." Journal of Engineering Sciences 9, no. 1 (2022): D14—D19. http://dx.doi.org/10.21272/jes.2022.9(1).d3.
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The article is devoted to a pilot study of the reverse-bladed pump. The characteristics of the reverse bladed pump are the identical parameters on flow, the head, power, energy efficiency on direct and the return operating modes (at rotation of a rotor of the pump both in one and to the opposite side). The model reversible axial pump with two impeller versions was tested on an experimental bench. The impellers were distinguished by the shape of the profile in the blade sections. The model reversible pump was structurally a reversible axial impeller placed in a cylindrical chamber. Studies were carried out at different angles of rotation of the impeller blades. The power characteristics of tested versions of the pump (impeller) at the design and under loading (unstable operation) modes are given. Low efficiency of the tested versions of the reversible pump compared to the conventional axial pumps is noted, primarily due to the strong influence of the secondary gradients of the pressure factor. The second reason is the profile separation of the flow from the blade surface, to which the tested reverse pump screens are predisposed.
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Fořt, Ivan, Miloslav Hošťálek, and Jaroslav Medek. "Liquid circulation in a cylindrical vessel with radial baffles and inclined blade impeller." Collection of Czechoslovak Chemical Communications 54, no. 6 (1989): 1599–611. http://dx.doi.org/10.1135/cccc19891599.
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Liquid circulation was studied in a cylindrical vessel with radial baffles under the turbulent flow regime of liquid agitated gradually with the following types of four inclined blade impellers: impeller with plane blades inclined at the angle of 25°; impeller with asymmetrically profiled blades at the angle of 30°-17°; impeller with strength-profiled blades. By solving the turbulent (vortex) analogy of the Stokes equations for the creeping (non-inertial) laminar flow, the streamline distribution (the Stokes stream function) in the bulk of agitated charge was obtained for each of impellers studied (relative size d/D = 1/3, relative distance from the bottom H2/D = 1/3, relative vessel filling H/D = 1), placed axisymmetrically in the vessel and pumping the liquid towards its flat bottom. The zero values of the Stokes stream function at the bottom, walls, and charge liquid level, and further the radial profiles of axial and radial component of mean velocity in the cross sections under and above the impeller obtained experimentally by the laser-doppler anemometry on the assumption of axial symmetry of the agitated system studied were set as the boundary conditions for the solution of the partial differential equation considered. It follows from the results obtained that the homogenous circulation of agitated charge at the relatively lowest value of the impeller power input is reached when agitating with the asymmetrically profiled blade impeller which therefore can successfully replace the propeller mixer with airfoil profiled blades.
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Chen, Qian, Yang Lihuan, Qi Zhipeng, and Yang Congxin. "Analysis of the axial force distribution characteristics of multistage pumps and its correlation with hydraulic property." Advances in Mechanical Engineering 14, no. 10 (October 2022): 168781322211305. http://dx.doi.org/10.1177/16878132221130565.
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As the centrifugal pump is running, the fluid usually flows into the impeller along pump shaft, and the fluid flows out radially by the force of the impeller. The force is mutual, so the impeller is also subjected to the reaction force of the fluid, but the distribution of this force on the blades is uneven. In addition, the front and rear shrouds of the impeller are asymmetric, which are the main causes of axial force. This paper adopts numerical calculation method studying the mechanism of axial force of impeller at all stages of multistage pump at various working conditions, and exploring the formation mechanism of shroud pressure differential force and blade twisting axial force and its variation laws of similarities and differences, analyzing the steady state and transient characteristics between axial force and hydraulic property of double-casing multistage pump. The results show that the rotational angular velocity of the fluid in the front and rear pump chamber at each stage impeller is distributed along the axial direction in three regions, the regions are pump body boundary layer, core region, and impeller boundary layer. The working surface and back surface of the blade twist have the high and low axial force area, and its distribution is staggered, at the same number of stages, the greater the flow rate, the smaller the blade twisting axial force. The shroud pressure differential force with the increase of impeller stages presents a linear increasing trend, conforms to the principle of linear superposition of cover pressure differential force. The total axial force pulsation of multi-stage pump is related to the number of secondary impeller blades, its primary frequency coincides with the secondary impeller blade frequency, increasing the flow rate can reduce the multi-stage pump axial force pulsation amplitude. The pulsation period of single-stage impeller head and efficiency are related to the number of impeller blades, the smaller the number of impeller stages, the stronger the pressure dynamic, and static interference effect of the impeller inlet and outlet. Rotation of the secondary impeller causes dynamic and static interference, which is the main reason for the pulsation of the axial force coefficient in double-casing multistage pumps, the pulsation intensity is related to the periodic generation and shedding of the blade vortex. The results of the study can be used as a reference for optimizing the axial force of double-casing multistage pumps.
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Foukrach, Mohammed, and Houari Ameur. "Effect of impeller blade curvature on the hydrodynamics and power consumption in a stirred tank." Chemical Industry and Chemical Engineering Quarterly 26, no. 3 (2020): 259–66. http://dx.doi.org/10.2298/ciceq190804003f.
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The performance of curved bladed turbines (CBTs) for the agitation of Newtonian fluids in cylindrical tanks is investigated. The efficiency of CBT is compared with that of the standard Rushton turbine. Also, effects of the blade height of the new designed impeller are highlighted. The computational fluid dynamics (CFD) study is performed to observe the axial, radial and tangential components of velocities, flow patterns and power consumption. The obtained results revealed that the increase of blade curvature reduces the power consumption. Also, a slight decrease of power number is observed in the turbulent flow regime within unbaffled tanks. In a comparison between the cases studied, the best axial circulation of fluid is given by the impeller with flat blades. The increase of the height of curved blades has generated a stronger tangential flow and enhanced the axial movement of fluid particles, but with further penalty in power input.
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Shen, Simin, Bensheng Huang, Si Huang, Shun Xu, and Shufeng Liu. "Research on Cavitation Flow Dynamics and Entropy Generation Analysis in an Axial Flow Pump." Journal of Sensors 2022 (June 22, 2022): 1–18. http://dx.doi.org/10.1155/2022/7087679.
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The entropy generation theory is introduced to investigate the effects of different NPSH and tip clearance size on the cavitation flow dynamics and mechanical energy dissipation intuitively and quantitatively within an axial flow pump through numerical simulations. The results indicate that main mechanical energy dissipation of the pump gathers in part impeller and diffuser, and most are turbulent dissipation. Meanwhile, the impeller is the largest place of mechanical energy dissipation of the pump under cavitation conditions, accounting for more than 50%. NPSH has significant effects on the cavitation pattern, which reflects on the field that the areas of attached sheet cavitation and tip leakage vortex cavitation around blades increase obviously with NPSH reducing under the tip clearance of 0.1% span. With NPSH decreasing, high regions of turbulent dissipation in the impeller mainly expands along blades and move downstream, with span S0.98 near the shroud having larger turbulent dissipation. Besides, high regions of turbulent dissipation are mainly distributed at the rear part of the cavity for every corresponding span of the impeller, which indicates that the turbulent dissipation has a strong relation with the cavitation pattern. In the impeller, the unstable flows cause cavity shedding at the rear of the cavity and wake flows near the blade trail induce higher turbulent kinetic energy, finally resulting in higher turbulent dissipation there. Under the same NPSH, areas of tip leakage vortex cavitation and areas of tip clearance cavitation around the tip both expand with the tip clearance increasing from 0.1% span to 0.8% span. And high areas of turbulent dissipation also are distributed at the rear of the cavity and moving downstream along the blade suction side, especially at span S0.98. Therefore, the tip clearance width mainly affects the cavitation development and turbulent dissipation distribution near the impeller’s shroud under same NPSH.
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Shen, Simin, Zhongdong Qian, and Bin Ji. "Numerical Analysis of Mechanical Energy Dissipation for an Axial-Flow Pump Based on Entropy Generation Theory." Energies 12, no. 21 (October 31, 2019): 4162. http://dx.doi.org/10.3390/en12214162.
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Mechanical energy dissipation is a major problem affecting hydraulic machinery especially under partial-load conditions. Owing to limitations of traditional methods in evaluating mechanical energy dissipation, entropy generation theory is introduced to study mechanical energy dissipation with varying discharge and tip clearance intuitively through numerical simulations in an axial-flow pump. Results show that the impeller and diffuser are the main domains of mechanical energy dissipation, respectively accounting for 35.32%–55.51% and 32.61%–20.42% of mechanical energy dissipation throughout the flow passage. The mechanical energy dissipation of the impeller has a strong relation with the hump characteristic and becomes increasingly important with decreasing discharge. Areas of high turbulent dissipation in the impeller are mainly concentrated near the blades’ suction sides, and these regions, especially areas near the shroud, extend with decreasing discharge. When the pump enters the hump region, the distributions of turbulent dissipation near the shroud become disordered and expand towards the impeller’s inlet side. Unstable flows, like flow separation and vortices, near the blades’ suction sides lead to the high turbulent dissipation in the impeller and hump characteristic. Turbulent dissipation at the tip decreases from the blade leading edge to trailing edge, and regions of high dissipation distribute near the leading edge of the blade tip side. An increase in tip clearance for the same discharge mainly increases areas of high turbulent dissipation near the shroud and at the tip of the impeller, finally reducing pump performance.
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Shi, Xiaobing, Jinling Lu, and Lianming Zhao. "Investigations on the influence of tandem blades on inner flow and performance characteristics of centrifugal pump." Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering 234, no. 1 (October 23, 2019): 46–55. http://dx.doi.org/10.1177/0954408919883730.
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Although significant advances have been made in tandem-blade technology for axial and centrifugal compressors, little attention has been paid to its application in centrifugal pumps. In this study, we propose a new tandem-blade design method for improving inner flow characteristics and overall performance of a centrifugal pump. With the SST k − ω turbulence model, three-dimensional turbulent flow fields in the centrifugal pump with tandem blades are simulated and analyzed. The effects of tandem blades on the inner flow and performance characteristics of the centrifugal pump are investigated. The predicted velocity and pressure distributions and flow behavior of the tandem-blade impeller are compared with those of a conventional single row blade impeller. It is indicated that the centrifugal tandem-blade impeller exhibits a significant advantage in terms of the uniformity of the impeller discharge flow. The tandem blades improve the jet-wake structure and uniformity of velocity and pressure distributions at the impeller outlet, and thus reduce the pressure fluctuation and hydraulic loss. Moreover, the hump phenomenon is eliminated or alleviated under low flow rate conditions, and the tandem-blade impeller has better hydraulic performance within a wider operating range as well as high reliability. This study provides a basis for the further development of the centrifugal pump with tandem blades.
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Zhang, Hong-li, Fan-yu Kong, Ai-xia Zhu, Fei Zhao, and Zhen-fa Xu. "Effect of Blade Outlet Angle on Radial Force of Marine Magnetic Drive Pump." Shock and Vibration 2020 (September 11, 2020): 1–18. http://dx.doi.org/10.1155/2020/8827333.
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To research the effects of the blade outlet angle on the performance and the radial force of the marine pump, the unsteady numerical simulation of the four different models is carried out. The radial forces on the impeller and the blades are obtained under different flow rate conditions. The time and frequency domain characteristics of radial resultant force on the impeller and the blades are analyzed and those of the impeller torque are researched. The results show that the radial forces of the impeller and the blades increase with the increase of the blade outlet angle at the same flow rate. With the same blade outlet angle, the radial forces decrease with the increase of the flow rate. The roundness of radial force vector diagram becomes more obvious with the decrease of the blade outlet angle. The root mean square (RMS) of radial force on the blades is about 30% of that on the impeller. The main frequency of radial force on the impeller and the blades is the axial passing frequency (APF), and that of impeller torque is the blade passing frequency (BPF), and there are peaks at the blade frequency multiplier. At the same flow rate, the main frequency and maximum fluctuation amplitudes on the impeller and the blades increase with the increase of the blade outlet angle. Meanwhile, the impeller torque increases with the increase of the blade outlet angle. With the same blade outlet angle, the main frequency, maximum fluctuation amplitudes, and the impeller torque decrease with the increase of the flow rate. The amplitude difference decreases with the increase of the flow rate. The blade outlet angle has an obvious greater influence on the radial forces and fluctuation at the small flow rate. The vibration test shows that the vibration intensities of model 25 and model 35 are less than 2.5 mm/s, and the vibration intensity of model 25 is about 0.2 mm/s less than that of model 35.
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Fang, Peng, Jianjun Du, and Shunzhou Yu. "Impeller (straight blade) design variations and their influence on the performance of a centrifugal blood pump." International Journal of Artificial Organs 43, no. 12 (April 20, 2020): 782–95. http://dx.doi.org/10.1177/0391398820913559.
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Introduction: The miniaturization of blood pumps has become a trend due to the advantage of easier transplantation, especially for pediatric patients. In small-scale pumps, it is much easier and more cost-efficient to manufacture the impeller with straight blades compared to spiral-profile blades. Methods: Straight-blade impeller designs with different blade angles, blade numbers, and impeller flow passage positions are evaluated using the computational fluid dynamics method. Blade angles (θ = 0°, 20°, 30°, and 40°), blade numbers ( N = 5, 6, 7, and 8), and three positions of impeller flow passage (referred to as top, middle, and bottom) are selected as the studied parametric values. Results: The numerical results reveal that with increasing blade angle, the pressure head and the hydraulic efficiency increase, and the average scalar shear stress and the normalized index of hemolysis decrease. The minimum radial force and axial thrust are obtained when θ equals 20°. In addition, the minimum average scalar shear stress and normalized index of hemolysis values are obtained when N = 6, and the maximum values are obtained when N = 5. Regarding the impeller flow passage position, the axial thrust and the stagnation area forming in the impeller eye are reduced as the flow passage height declines. Conclusion: The consideration of a blade angle can greatly improve the performance of blood pumps, although the influence of the blade number is not very easily determined. The bottom position of the impeller flow passage is the best design.
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Spasić, Živan, Miloš Jovanović, Jasmina Bogdanović-Jovanović, and Saša Milanović. "NUMERICAL INVESTIGATION OF THE INFLUENCE OF THE DOUBLY CURVED BLADE PROFILES ON THE REVERSIBLE AXIAL FAN CHARACTERISTICS." Facta Universitatis, Series: Mechanical Engineering 18, no. 1 (March 27, 2020): 057. http://dx.doi.org/10.22190/fume171128002s.
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Abstract. In reversible axial fans a change in the direction of the impeller rotation is accompanied with a change in the direction of the working fluid flow. To satisfy the flow reversibility, the impeller blades are usually designed with straight symmetrical profiles. The flow reversibility may also be achieved by using asymmetrical blade profiles in which, to satisfy the equality of the leading and trailing angle of the profiles, the mean line of the profile has to have a double curvature in the shape of the stretched letter 'S'. The paper numerically investigates the influence of the doubly curved blade profiles on the reversible axial fan characteristics. Numerical simulations are carried out on an axial fan only with the impeller, with the blades that have double-curved mean line profiles for different values of the angles at the profile ends. For numerical simulation the ANSYS CFX software package is used. Results of the numerical simulation are shown in diagrams Δp(Q), h(Q) and P(Q) at different angles of the profile ends. On the basis of the simulation and analysis of the characteristics, appropriate conclusions are proposed, along with the most advantageous profile of the blades.
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Zhang, Weijie, Jianping Yuan, Banglun Zhou, Hao Li, and Ye Yuan. "The influence of axial-flow fan trailing edge structure on internal flow." Advances in Mechanical Engineering 10, no. 11 (November 2018): 168781401881174. http://dx.doi.org/10.1177/1687814018811745.
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Axial-flow fan with advantages such as large air volume, high head pressure, and low noise is commonly used in the work of air-conditioner outdoor unit. In order to investigate the internal flow mechanism of the axial-flow fan with different trailing edge structures of impellers, four kinds of impellers were designed, and numerical simulation and experiment were deployed in this article. The pressure distribution on the blades surface and distribution of vorticity in impellers were obtained using numerical simulation. Distribution of blade loading and velocity at the circumference are discussed. The relationship between the wideband noise and the trailing edge was established based on the experiment results. The results show that after the optimization of the trailing edge structure, the distribution of vorticity near the trailing edge of the blade is more uniform, especially at the trailing edge of 80% of the chord length of the suction surface. From the blade height position of 70% to the impeller tip, the pressure on the surface rapidly increases due to the tip vortex and the vortex shedding on the blade edge occurred in the top region of impeller. The pressure fluctuation amplitude at the trailing edge structure of the tail-edge optimization structure is smaller. In the distribution of blade loading, the three tail-edge optimization structures have smaller pressure fluctuations and pressure differences at the trailing edge structure. It is extremely important to control the fluctuation amplitude at the trailing edge. The amplitude of low-frequency sound pressure level of optimizing the trailing edge structure decreases obviously in the range of 50–125 Hz, and the optimization structure of trailing edge has an obvious effect on low-frequency wideband noise.
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Nishi, Yasuyuki, and Junichiro Fukutomi. "Component Analysis of Unsteady Hydrodynamic Force of Closed-Type Centrifugal Pump with Single Blades of Different Blade Outlet Angles." International Journal of Rotating Machinery 2015 (2015): 1–17. http://dx.doi.org/10.1155/2015/419736.
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Single-blade centrifugal impellers for sewage systems undergo both unsteady radial and axial thrusts. Therefore, it is extremely important for the improvement of pump reliability to quantitatively grasp these fluctuating hydrodynamic forces and determine the generation mechanism behind them. In this study, we conducted component analyses of radial and axial thrusts of closed, single-blade centrifugal pumps with different blade outlet angles by numerical analysis while considering leakage flow. The results revealed the effect of the blade outlet angle on the components of radial and axial thrusts. For increased flow rates, the time-averaged values of the pressure component were similar for all impellers, although its fluctuating components were higher for impellers with larger blade outlet angles. Moreover, the fluctuating inertia component of the impeller with a blade outlet angle of 8° decreased as the flow rate increased, whereas those with 16° and 24° angles increased. Therefore, the radial thrust on the hydraulic part was significantly higher for impellers with high blade outlet angles.
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Quan, Hui, Yanan Li, Lei Kang, Xinyang Yu, Kai Song, and Yongkang Wu. "Influence of Blade Type on the Flow Structure of a Vortex Pump for Solid-Liquid Two-Phase Flow." Machines 9, no. 12 (December 15, 2021): 353. http://dx.doi.org/10.3390/machines9120353.
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Vortex pumps have good non-clogging performance owing to their impellers being retracted into retraction cavities, but they are much less efficient than ordinary centrifugal pumps. In this paper, numerical simulations were performed on a model of the 150WX200-20 vortex pump for four different blade types, and the influence of blade structure on pump performance was determined. The simulations revealed the existence of axial vortices in the flow passage between the blades in the impeller region. The geometric characteristics of these axial vortices were more regular in two-phase solid-liquid flow than single-phase liquid flow. The presence of the solid phase reduced the vortex strength compared with the single-phase flow and suppressed the increase in size of the secondary circulation vortex. It was found, however, that the blade shape had a greater influence on the circulating flow than the presence of the solid phase. The flow state of the medium flowing out of the impeller domain had a direct effect on the circulating flow with this effect being related to the law governing the flow of the medium in the flow channel between the blades. It was found that the performance of a front-bent blade was the best and that of a curved blade the worst. This influence of blade type on the internal flow structure was used to further explain the relationship between the internal flow structure and the external characteristics of the vortex pump, the understanding of which is crucial for blade selection and hydraulic optimization.
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Kan, Kan, Yuan Zheng, Huixiang Chen, Jianping Cheng, Jinjin Gao, and Chunxia Yang. "Study into the Improvement of Dynamic Stress Characteristics and Prototype Test of an Impeller Blade of an Axial-Flow Pump Based on Bidirectional Fluid–Structure Interaction." Applied Sciences 9, no. 17 (September 2, 2019): 3601. http://dx.doi.org/10.3390/app9173601.
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This paper performed a numerical study into the dynamic stress improvement of an axial-flow pump and validated the simulation results with a prototype test. To further analyze the dynamic stress characteristics of impeller blades of axial-flow pumps, a bidirectional fluid–structure interaction (FSI) was applied to numerical simulations of the unsteady three-dimensional (3-D) flow field of the whole flow system of an axial-flow pump, and the gravity effect was also taken into account. In addition, real-structure-based single-blade finite element model was established. By using the finite element method, a calculation of the blade’s dynamic characteristics was conducted, and its dynamic stress distribution was determined based on the fourth strength theory. The numerical results were consistent with the prototype tests. In a rotation cycle, the dynamic stress of the blade showed a tendency of first increasing, and then decreasing, where the maximum value appeared in the third quadrant and the minimum appeared in the first quadrant in view of the gravity effect. A method for reducing the stress concentration near the root of impeller blades was presented, which would effectively alleviate the possibility of cracking in the unreliable region of blades. Simultaneously, an experimental method for the underwater measurement of the dynamic stress of prototypical hydraulic machinery was put forward, which could realize the underwater sealing of data acquisition instruments on rotating machinery and the offline collection of measured data, finally effectively measuring the stress of underwater moving objects.
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Tao, Ran, Ruofu Xiao, and Fujun Wang. "Detached eddy simulations for high speed axial flow fuel pumps with swept and straight blade impellers." Engineering Computations 33, no. 8 (November 7, 2016): 2530–45. http://dx.doi.org/10.1108/ec-06-2015-0165.
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Purpose High speed axial flow pumps are widely used in aircraft fuel systems. Conventional axial flow pumps often generate radial secondary flows at partial-load conditions which influence the flow structure and form a “saddle-shaped” region in the Q-H curve that can destabilize the operation. Thus, the “saddle-shaped” Q-H region must be eliminated. The paper aims to discuss these issues. Design/methodology/approach The swept stacking method is often used for radial flow control in turbo-machinery impeller blade design. Hence, this study uses the swept stacking method to design a high speed axial flow pump. The detached eddy simulation method and experiments are used to compare the performance of a swept blade impeller in a high speed axial fuel pump with the original straight blade impeller. Both the pump performance and internal flow characteristics are studied. Findings The results show separation vortices in the impeller with the straight blade design at partial-load conditions that are driven by the rotating centrifugal force to gather near the shroud. The swept geometry provides an extra force which is opposite to the rotating centrifugal force that creates a new radial equilibrium which turns the flow back towards the middle of the blade which eliminates the vortices and the “saddle-shaped” Q-H region. The swept blade impeller also improves the critical cavitation performance. Analysis of the pressure pulsations shows that the swept blade design does not affect the stability. Originality/value This study is the initial application of swept blades for axial flow liquid pumps. The results show how the swept stacking changes the radial equilibrium of the high density, high viscosity flow and the effects on the mass transfer and pressure pulsations. The swept blade effectively improves the operating stability of high speed fuel pumps.
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Zhou, Bang Lun, Jian Ping Yuan, Zhi Xia He, and Feng Hong. "Effect of Different Airfoils on Performance of Axial Fan." Advanced Materials Research 945-949 (June 2014): 928–34. http://dx.doi.org/10.4028/www.scientific.net/amr.945-949.928.
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Airfoil has great influence on the performance of axial fan. In order to study performance of axial fan. Four kinds of airfoils have been applied to optimize the impeller of axial fan. The 3D internal flows of the axial fan under different operating conditions were simulated based on a steady numerical method in ANSYS CFX 14.5. The results show that the curve of total pressure of the fan with LS airfoil blades is slightly steeper, and that of the fan with CLARK-Y(C=11.7%) (C is the blade thickness ratio) airfoil blades is relatively flat. The total pressure of the axial fan with CLARK-Y(C=11.7%) blades is highest among others. While achieving the highest efficiency in all the operating conditions except the lowest flow rate. Moreover, the blades loading of the CLARK-Y(C=11.7%) airfoil blades fan is entirely more uniform than that in others. The turbulent kinetic energy distribution on the leading edge of blades shows that the axial fan with CLARK-Y(C=11.7%) airfoil blades fan can improve the turbulent kinetic energy effectively.
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Senoo, Y., and M. Ishida. "Pressure Loss Due to the Tip Clearance of Impeller Blades in Centrifugal and Axial Blowers." Journal of Engineering for Gas Turbines and Power 108, no. 1 (January 1, 1986): 32–37. http://dx.doi.org/10.1115/1.3239882.
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The pressure loss based on the tip clearance of impeller blades consists of the pressure loss induced by the leakage flow through the clearance and the pressure loss for supporting fluid against the pressure gradient in the channels and in the thin annular clearance space between the shroud and the impeller. Equations to evaluate these losses are derived and the predicted efficiency drop is compared with experimental data for two types of centrifugal impellers. Furthermore, the equations are simplified for axial impellers as a special case, and the predicted efficiency drop is compared with the experimental data for seven cases in the literature. Fair agreement demonstrates plausibility of the present model.
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Jirout, Tomáš. "Pumping Capacity of Pitched Blade Multi-Stage Impellers." Chemical and Process Engineering 35, no. 1 (March 1, 2014): 47–53. http://dx.doi.org/10.2478/cpe-2014-0004.
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Abstract This paper extends knowledge about flow in an agitated batch with pitched blade multi-stage impellers. Effects of various geometrical parameters (blade number, distance between impellers) of pitched blade multi-stage impellers on pumping ability have been investigated. Axial velocity profiles were measured by LDA (Laser Doppler Anemometry). Axial pumping capacities were obtained by integration of measured axial velocity profiles in outflow from impellers. Main attention was focused on the effect of the distance between impellers in multi-stage configurations, on their pumping capacity and flow in the mixing bath in comparison with an independently operating pitched blade impeller with the same geometry. In case of a relatively close distance between impellers H3/d = 0.5 - 0.75, the multi-stage impeller creates only one circulation loop and the impellers itself behave identically as pumps in series. However for relative higher distance of impellers than H3/d = 1.25, the multi-stage impeller creates two separated circulation loops.
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Sun, Zhuangzhuang, Fangping Tang, Lijian Shi, and Haiyu Liu. "Multi-Conditional Optimization of a High-Specific-Speed Axial Flow Pump Impeller Based on Machine Learning." Machines 10, no. 11 (November 7, 2022): 1037. http://dx.doi.org/10.3390/machines10111037.
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In order to widen the range of high-efficiency area of a high-specific-speed axial flow pump and to improve the operating efficiency under non-design conditions, the parameters of the axial flow pump blades were optimized. An optimization system based on computational fluid dynamics (CFD), optimized Latin hypercube sampling (OLHS), machine learning (ML), and multi-island genetic algorithm (MIGA) was established. The prediction effects of three machine learning models based on Bayesian optimization, support vector machine regression (SVR), Gaussian process regression (GPR), and fully connected neural network (FNN) on the performance of the axial flow pump were compared. The results show that the GPR model has the highest prediction accuracy for the impeller head and weighted efficiency. Compared to the original impeller, the optimized impeller is forward skewed and backward swept, and the weighted efficiency of the impeller increases by 1.31 percentage points. The efficiency of the pump section at 0.8Qd, 1.0Qd, and 1.2Qd increases by about 1.1, 1.4, and 1.6 percentage points, respectively, which meets the optimization requirements. After optimization, the internal flow field of the impeller is more stable; the entropy production in the impeller reduces; the spanwise distribution of the total pressure coefficient and the axial velocity coefficient at the impeller outlet are more uniform; and the flow separation near the hub at the blade trailing edge is restrained. This research can provide a reference for the efficient operation of pumping stations and the optimal design of axial flow pumps under multiple working conditions.
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Neuhaus, L., J. Schulz, W. Neise, and M. Möser. "Active control of the aerodynamic performance and tonal noise of axial turbomachines." Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 217, no. 4 (January 1, 2003): 375–83. http://dx.doi.org/10.1243/095765003322315432.
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Two projects on axial fans are presented in this paper. The first aims at improving the aerodynamic performance and reducing the tip clearance noise caused by the rotating instability. This is achieved by injecting air into the radial gap between the impeller blade tips and the fan casing. Steady air injection with small mass flows results in remarkable reductions in the noise level along with improved aerodynamic performance. Larger injected mass flows give significant improvements in the aerodynamic performance at the expense of an increased overall noise level. The second project uses flow control actively to reduce the blade passage frequency (BPF) level. Experimental results are presented for steady jets injected into the main flow and cylindrical rods at axial positions downstream of the impeller blades. The method is successful for higher-order mode sound fields where the BPF level is reduced by up to 20.5 dB.
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Shi, Lijian, Changxin Wu, Li Wang, Tian Xu, Yuhang Jiang, Yao Chai, and Jun Zhu. "Influence of Blade Angle Deviation on the Hydraulic Performance and Structural Characteristics of S-Type Front Shaft Extension Tubular Pump Device." Processes 10, no. 2 (February 8, 2022): 328. http://dx.doi.org/10.3390/pr10020328.
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When the axial-flow pump is running, the blade angle is not fully adjusted or there are errors in the manufacture of the blades, which will lead to inconsistent blade placement angles during operation, and which will reduce the efficiency of the axial-flow pump. This paper uses the research methods of numerical simulation and model experiments to analyze the hydraulic performance and impeller structure characteristics of each flow components under different schemes when the angles of each blade of the S-type front shaft extension tubular pump device are inconsistent. The research phenomenon is that the guide vane greatly recovers the flow velocity circulation at the impeller outlet, reduces the hydraulic loss of guide vane, and widens the best efficiency range with an increase in guide vane blade angle. When the blade angle deviation occurs, the flow field of each blade channel affects each other, and the maximum decrease in the best efficiency is up to 7.78%, mainly due to the increased hydraulic loss in the outlet channel. The blade angle deviation will also affect the maximum equivalent stress and maximum deformation of the impeller, which is more obvious in large flow conditions. Inconsistent blade angles seriously affect the operating efficiency of the water pump and water pump device, and make the structural characteristics of the impeller worse.
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Miner, Steven M. "Evaluation of Blade Passage Analysis Using Coarse Grids." Journal of Fluids Engineering 122, no. 2 (February 10, 2000): 345–48. http://dx.doi.org/10.1115/1.483263.
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This paper presents the results of a study using coarse grids to analyze the flow in the impellers of an axial flow pump and a mixed flow pump. A commercial CFD code (FLOTRAN) is used to solve the 3-D Reynolds Averaged Navier Stokes equations in a rotating cylindrical coordinate system. The standard k−ε turbulence model is used. The meshes for this study use 22,000 nodes and 40,000 nodes for the axial flow impeller, and 26,000 nodes for the mixed flow impeller. Both models are run on a SPARCstation 20. This is in contrast to typical analyses using in excess of 100,000 nodes. The smaller mesh size has advantages in the design environment. Stage design parameters for the axial flow impeller are, rotational speed 870 rpm, flow coefficient ϕ=0.13, head coefficient ψ=0.06, and specific speed 2.97 (8101 US). For the mixed flow impeller the parameters are, rotational speed 890 rpm, flow coefficient ϕ=0.116, head coefficient ψ=0.094, and specific speed 2.01 (5475 US). Evaluation of the models is based on a comparison of circumferentially averaged results to measured data for the same impeller. Comparisons to measured data include axial and tangential velocities, static pressure, and total pressure. A comparison between the coarse and fine meshes for the axial flow impeller is included. Results of this study show that the computational results closely match the shapes and magnitudes of the measured profiles, indicating that coarse CFD models can be used to accurately predict performance. [S0098-2202(00)02202-1]
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Tan, Ching Ying, Mohd Izzudin Izzat Zainal Abidin, and Mohd Usman Mohd Junaidi. "Effects of impeller designs and configurations on the flow field in multiple impeller system using Computational Fluid Dynamics (CFD)." Research Communication in Engineering Science & Technology 5 (April 1, 2022): 1–9. http://dx.doi.org/10.22597/rcest.v5.134.
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The work presents the computational study of the flow field in multiple impellers stirred vessel with various impeller types and configurations at 300rpm, 450rpm and 600rpm. Three types of impellers are investigated, namely the pitched blade impeller (PB), flat blade impeller (FB) and sawtooth impeller (ST). In this study, the flow patterns, turbulent kinetic energy dissipation, and power consumption in dual impellers system have been studied using computational fluid dynamics (CFD) by employing the multiple reference frame (MRF) and realizable k-ɛ turbulence model. The results from PBFB and reversed FBPB indicate efficient and powerful mixing with the merging of flows from both impellers that circulates the entire vessel. Besides, the FB and ST configuration exhibits the mixing characteristics that enhance both dispersion and mixing homogeneity. It is proven in this study that the combination of axial and radial impellers improves the weak mixing zones in the stirred vessel by the complex flow patterns produced. On top of that, utilizing two different impellers could achieve two mixing objectives in a system with the exceptional features of each impeller. The results establish promising effects of the reverse rotation in axial impellers and the arrangement of two different impellers in a multiple impeller system. With the rapid growth of industrialization, understanding the fluid dynamics in a multiple impeller stirred vessel is fundamental to optimize and scale up industrial mixing operations. Hence, the empirical findings in this study will be beneficial in selecting the suitable combination of impellers and the orientations that will enhance industrial mixing operations. Apart from that, the present work also illustrates that the computational technique used can be extremely valuable in determining the fluid dynamics in complex multiple impeller system which is challenging to analyse experimentally.
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Ni, Shaosong, Wenbin Cao, Jun Xu, Yingdong Wang, and Wei Zhang. "Effects of an Inclined Blade on the Performance of a Sirocco Fan." Applied Sciences 9, no. 15 (August 2, 2019): 3154. http://dx.doi.org/10.3390/app9153154.
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The impeller is the primary working component of centrifugal fans, whose internal flow directly determines the performance of the whole system. This work presents a numerical investigation by using ANSYS-Fluent on the internal flow of a Sirocco fan to investigate the effects of the inclination angle of the blades on the fan performance. The orientation of the blade for the baseline model is strictly along the axial direction, while three inclination angles, i.e., 3.5°, 7.0°, and 10.5°, are chosen for the inclined blades of the modified impeller to improve the aerodynamic performance of the fan. The effects of the inclined blade are demonstrated by the variations in static pressure, efficiency, and pressure and velocity distributions at various inclination angles. The computed results reveal that there is an optimum inclination angle, which produces the best aerodynamic performance.
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Baek, Seok Heum, Won Hyuk Jung, and Sangmo Kang. "Shape Optimization of Impeller Blades for Bidirectional Axial Flow Pump." Transactions of the Korean Society of Mechanical Engineers B 36, no. 12 (December 1, 2012): 1141–50. http://dx.doi.org/10.3795/ksme-b.2012.36.12.1141.
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Qiu, Li Jun, and Su Ying Xu. "The Turbocharger Exhaust Gas Regulator Design and Analysis." Applied Mechanics and Materials 644-650 (September 2014): 485–88. http://dx.doi.org/10.4028/www.scientific.net/amm.644-650.485.
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In order to adapt to the needs of internal combustion engine speed variation of the turbocharger. Using waste gas regulator control exhaust gas inlet device. The effect of exhaust gas regulator is for adjusting the gas flow velocity and direction. When the internal combustion engine running at low speed raising the impeller speed. Exhaust gas regulator and axial moving blades rotating blades of two kinds of structure. The axial moving blade structure is changing the way nozzle ring opening work. Rotating blade structure is working on changing the way of blade Angle. Exhaust gas to adjust the turbocharger is a control of internal combustion engine air pressurization value of the speed changes.
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Zhang, De Sheng, Wei Dong Shi, Yan Xu, and Fei Long. "Numerical Simulation of Solid Particles Movement in the Axial Flow Impeller and Wear Experiment." Applied Mechanics and Materials 152-154 (January 2012): 1572–77. http://dx.doi.org/10.4028/www.scientific.net/amm.152-154.1572.
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The performance curves of a submersible axial flow pump were predicted based on mixture multiphase flow model, RNG k-ε turbulence model and SIMPLEC algorithm, and the solid-liquid two-phase flow in the impeller was simulated. The numerical results show that the performance prediction of the head and efficiency curves show good agreement with the experimental data in the whole flow rate range, and the solid particles in the impeller are mainly distributed on pressure side of blades, while less on the suction side.The solid particles are mainly concentrated in the blade inlet and region near the hub of the pressure side. The experimental results also show that the blade pressure sides have serious erosion, particularly near the hub, but less wear and tear on the suction side.The accuracy of the numerical simulation results are verified by the experiments.
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Дорошенко, Екатерина Викторовна, Михаил Владимирович Хижняк, and Юрий Матвеевич Терещенко. "ВПЛИВ ГУСТОТИ РЕШІТКИ НА АЕРОДИНАМІЧНУ НАВАНТАЖЕНІСТЬ РОБОЧОГО КОЛЕСА ОСЬОВОГО ВЕНТИЛЯТОРА." Aerospace technic and technology, no. 4 (August 28, 2020): 38–43. http://dx.doi.org/10.32620/aktt.2020.4.05.
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The main requirements that apply to axial fans and axial compressors of aircraft gas turbine engines include minimum dimensions and weight; high aerodynamic load; high coefficient of performance; wide range of steady work; high reliability. For gas turbine engines, the requirements of minimum weight and dimensions are especially important, since the engines must provide flights at high velocities and altitudes. This study aims to assess the effect of the solidity of the impeller fan on the average radius on the aerodynamic loading of the impeller of an axial fan for an engine with a high bypass ratio. The object of the study is the impeller of the fan. The solidity of the impeller fan on the average radius varied in the range from 1.8 to 0.82, the number of blades of the impeller fan varied from 33 to 15, respectively. The studies in this work were carried out by the method of numerical experiment. The flow in the axial fans was simulated by solving the system of Navier-Stokes equations, which were closed by the SST turbulent viscosity model. Based on the analysis of the results of the study, an assessment is made of the influence of the solidity of the impeller fan at an average radius on the aerodynamic loading of the impeller of an axial fan for an engine with a high bypass ratio. The research results showed that with a decrease in the solidity of the impeller fan at an average radius of 1.8 to 0.82 in operating modes with an axial inlet velocity of 80 to 120 m / s, the impeller fan pressure ratio decreases by 0.11 ... 3.2 %. The maximum decrease in the fan pressure ratio increase for the fan impeller with the parameters studied is 3.2 %, with a decrease in the number of fan blades from 33 to 15, while the total weight of the blades decreases by 54.55 %. The decrease in the solidity on the average radius of the impeller of the studied fan leads to a decrease in the relative sizes of the low-velocity zones at the sleeve and on the periphery and to a decrease in the level of flow unevenness. A further reduction in the level of flow non-uniformity behind the fan is possible when using the boundary layer control in the fan - this is the task of subsequent studies.
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Kalinkevych, M., V. Ihnatenko, O. Bolotnikova, and O. Obukhov. "Design of high efficiency centrifugal compressors stages." Refrigeration Engineering and Technology 54, no. 5 (October 31, 2018): 4–9. http://dx.doi.org/10.15673/ret.v54i5.1239.
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The modern trend in compressor industry is an extension of the use of multi-shaft centrifugal compressors. Multi-shaft compressors have a number of advantages over single-shaft. The design of such compressors gives opportunity to use an axial inlet for all stages and select the optimum rotational speed for each pair of impellers, which, along with the cooling of the gas after each stage, makes possible to achieve high levels of efficiency. The design of high-efficiency centrifugal compressor stages can be performed on the basis of highly effective stage elements. Such elements are: impellers with spatial blades, vaned and channel diffusers with given velocity distribution. In this paper, impellers with axial-radial blades are considered. The blade profile is determined by the specified pressure distribution along the blade. Such design improves the structure of the gas flow in the interblade channels of the impeller, which leads to an increase in its efficiency. Characteristics of loss coefficients from attack angles for impellers were obtained experimentally. Vaned and channel diffusers, the characteristics of which are given in this article, are designed with the given velocity distribution along the vane. Compared to the classic type of diffuser, such diffusers have lower losses and a wider range of economical operation. For diffusers as well as for impellers, characteristics of loss coefficients from attack angles were obtained. High efficient impellers and diffusers and obtained gas-dynamic characteristics were used in the design of a multi-shaft compressor unit for the production of liquefied natural gas. The initial pressure of the unit is 3bar. The obtained characteristics of loss coefficients from attack angles for the considered impellers and diffusers make it possible to calculate the gas-dynamic characteristics of high-efficient centrifugal compressors stages. The high-efficient centrifugal compressors stages can be designed using high-efficient elements, such as: impeller with spatial blades and vaned diffuser with given velocity distribution.
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Cao, Shuliang, Guoyi Peng, and Zhiyi Yu. "Hydrodynamic Design of Rotodynamic Pump Impeller for Multiphase Pumping by Combined Approach of Inverse Design and CFD Analysis." Journal of Fluids Engineering 127, no. 2 (October 1, 2004): 330–38. http://dx.doi.org/10.1115/1.1881697.
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A combined approach of inverse method and direct flow analysis is presented for the hydrodynamic design of gas-liquid two-phase flow rotodynamic pump impeller. The geometry of impeller blades is designed for a specified velocity torque distribution by treating the two-phase mixture as a homogeneous fluid under the design condition. The three-dimensional flow in the designed impeller is verified by direct turbulent flow analysis, and the design specification is further modified to optimize the flow distribution. A helical axial pump of high specific speed has been developed. To obtain a favorable pressure distribution the impeller blade was back-loaded at the hub side compared to the tip side. Experimental results demonstrate that the designed pump works in a wide flow rate range until the gas volume fraction increases to over 50% and its optimum hydraulic efficiency reaches to 44.0% when the gas volume fraction of two-phase flow is about 15.6%. The validity of design computation has been proved.
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Nishi, Yasuyuki, and Junichiro Fukutomi. "Effect of Blade Outlet Angle on Unsteady Hydrodynamic Force of Closed-Type Centrifugal Pump with Single Blade." International Journal of Rotating Machinery 2014 (2014): 1–16. http://dx.doi.org/10.1155/2014/838627.
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Geometrically, the single-blade centrifugal impeller, commonly used today as a sewage pump, is not axially symmetric. For this reason, the static pressure around the impeller fluctuates greatly when the impeller is rotating, and not only the radial thrust but also the axial thrust shows large fluctuations. Therefore, it is extremely important for the improvement of pump reliability to quantitatively grasp these fluctuating hydrodynamic forces. In this study, we investigated the unsteady hydrodynamic forces in a closed-type centrifugal pump with a single blade for different blade outlet angles using a numerical analysis that takes into account both experiment and the leakage flow. The results clearly showed the effect of the blade outlet angle on that act on the impeller. The root-mean-square value of the fluctuating component of the total radial thrust was roughly the same for whichever impeller at low flow rate, but at high flow rates, the value increased for impellers with larger blade outlet angles. Moreover, when the leakage flow rate increased with increasing static pressure around the impeller, such that the rear and front shroud parts were subject to high pressure, the absolute value of the axial thrust on both these parts increased.
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Spasic, Zivan, Sasa Milanovic, Vanja Sustersic, and Boban Nikolic. "Low-pressure reversible axial fan with straight profile blades and relatively high efficiency." Thermal Science 16, suppl. 2 (2012): 593–603. http://dx.doi.org/10.2298/tsci120503194s.
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The paper presents the design and operating characteristics of a model of reversible axial fan with only one impeller, whose reversibility is achieved by changing the direction of rotation. The fan is designed for the purpose of providing alternating air circulation in wood dryers in order to reduce the consumption of electricity for the fan and increase energy efficiency of the entire dryer. To satisfy the reversibility of flow, the shape of the blade profile is symmetrical along the longitudinal and transversal axes of the profile. The fan is designed with equal specific work of all elementary stages, using the method of lift forces. The impeller blades have straight mean line profiles. The shape of the blade profile was adopted after the numerical simulations were carried out and high efficiency was achieved. Based on the calculation and conducted numerical simulations, a physical model of the fan was created and tested on a standard test rig, with air loading at the suction side of the fan. The operating characteristics are shown for different blade angles. The obtained maximum efficiency was around 0.65, which represents a rather high value for axial fans with straight profile blades.
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Hamkins, C. P., and R. D. Flack. "Laser Velocimeter Measurements in Shrouded and Unshrouded Radial Flow Pump Impellers." Journal of Turbomachinery 109, no. 1 (January 1, 1987): 70–76. http://dx.doi.org/10.1115/1.3262072.
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Shrouded and unshrouded versions of a four-vaned radial flow impeller with a design flow coefficient of 0.063 were tested in a volute pump using a two-component frequency-shifted laser velocimeter. Velocity profiles were measured at six flow rates and at four radial and six circumferential positions in the volute. The variations of the velocity from blade to blade and in the axial direction were measured and are presented. A passage vortex caused by tip leakage and relative casing wall velocity was found in the unshrouded impeller. The tip leakage did not accumulate in the suction wake region; the suction wake region was only 30 to 50 percent as large in the unshrouded impeller as compared to the shrouded impeller. The slip was 30 percent higher in the unshrouded impeller and the variation of slip with flow rate is presented. At no measured position in the impellers did the slip factor reach unity; the closest approach was 0.90. Reverse loadings of the vanes at outer radii were found for flow rates below the impeller/volute matching point for both impellers.
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Yang, Li, Ouyang Hua, and Du Zhao-Hui. "Optimization Design and Experimental Study of Low-Pressure Axial Fan with Forward-Skewed Blades." International Journal of Rotating Machinery 2007 (2007): 1–10. http://dx.doi.org/10.1155/2007/85275.
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This paper presents an experimental study of the optimization of blade skew in low pressure axial fan. Using back propagation (BP) neural network and genetic algorithm (GA), the optimization was performed for a radial blade. An optimized blade is obtained through blade forward skew. Measurement of the two blades was carried out in aerodynamic and aeroacoustic performance. Compared to the radial blade, the optimized blade demonstrated improvements in efficiency, total pressure ratio, stable operating range, and aerodynamic noise. Detailed flow measurement was performed in outlet flow field for investigating the responsible flow mechanisms. The optimized blade can cause a spanwise redistribution of flow toward the blade midspan and reduce tip loading. This results in reduced significantly total pressure loss near hub and shroud endwall region, despite the slight increase of total pressure loss at midspan. In addition, the measured spectrums show that the broadband noise of the impeller is dominant.
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Gao, Shuling, Lingguo Meng, Dezhou Wei, Qiang Zhao, Xuetao Wang, and Duanxu Hou. "Influence of the Impeller Diameter and Off-Bottom Clearance on the Flow Velocity Distribution Characteristics Near the Bottom inside a Flotation Machine." Minerals 11, no. 1 (December 29, 2020): 31. http://dx.doi.org/10.3390/min11010031.
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The solid particle suspension inside a flotation machine is significantly dependent on the flow field, particularly the flow hydrodynamics characteristics near the bottom of the flotation machine. In this study, a laser Doppler anemometer (LDA) was utilized to investigate the influence of the impeller diameter and the impeller off-bottom clearance of a flotation machine on the flow velocity distribution characteristics near its bottom. The results showed that centripetal, centrifugal, and transitional spiral ascending vortexes were generated for different cases of the impeller variables. The impeller diameter and the off-bottom clearance were found to have a significant and interactive influence on the flow pattern, radial and axial velocities, velocity vector distribution, and axial fluctuating root mean square (RMS) velocity characteristics. When the centripetal flow was generated with a large impeller diameter and a small off-bottom clearance, the vortex stability was improved, the low-velocity distribution area was reduced near the bottom center, and the high axial RMS velocity distribution area was extended and became more consistent. The latter provided an advantageous condition for the momentum transfer between the liquid flow and the solid particles, as well as the airflow. However, the axial RMS velocity in the centrifugal flow formed in other cases of the impeller variables was less than that in the centripetal flow. Although the increase in the impeller off-bottom clearance contributed to increasing the velocity magnitude, this is certainly disadvantageous to the service life of the impeller blades, as expected from the high-velocity area extension. These results may provide a reference for the impeller design and optimization of a KYF (Kuang Yuan Flotation) flotation machine, as well as a basis for further investigation on the behavior of the dispersed phases inside a flow field.
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Throckmorton, A. L., J. Kapadia, and D. Madduri. "Mechanical axial flow blood pump to support cavopulmonary circulation." International Journal of Artificial Organs 31, no. 11 (November 2008): 970–82. http://dx.doi.org/10.1177/039139880803101107.
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We are developing a collapsible, percutaneously inserted, axial flow blood pump to support the cavopulmonary circulation in infants with a failing single ventricle physiology. An initial design of the impeller for this axial flow blood pump was performed using computational fluid dynamics analysis, including pressure-flow characteristics, scalar stress estimations, blood damage indices, and fluid force predictions. A plastic prototype was constructed for hydraulic performance testing, and these experimental results were compared with the numerical predictions. The numerical predictions and experimental findings of the pump performance demonstrated a pressure generation of 2–16 mm Hg for 50–750 ml/min over 5,500–7,500 RPM with deviation found at lower rotational speeds. The axial fluid forces remained below 0.1 N, and the radial fluid forces were determined to be virtually zero due to the centered impeller case. The scalar stress levels remained below 250 Pa for all operating conditions. Blood damage analysis yielded a mean residence time of the released particles, which was found to be less than 0.4 seconds for both flow rates that were examined, and a maximum residence time was determined to be less than 0.8 seconds. We are in the process of designing a cage with hydrodynamically shaped filament blades to act as a diffuser and optimizing the impeller blade shape to reduce the flow vorticity at the pump outlet. This blood pump will improve the clinical treatment of patients with failing Fontan physiology and provide a unique catheter-based therapeutic approach as a bridge to recovery or transplantation.
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Li, Ziliang, Xingen Lu, Yanfeng Zhang, Ge Han, Chengwu Yang, and Shengfeng Zhao. "Numerical investigation of a highly loaded centrifugal compressor stage with a tandem bladed impeller." Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 232, no. 3 (August 17, 2017): 240–53. http://dx.doi.org/10.1177/0957650917725406.
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This study numerically investigated a highly loaded centrifugal compressor stage with various tandem-designed impellers and a wedge diffuser using a state-of-the-art multi-block flow solver to better understand the fundamental mechanism of tandem impellers. The flow topologies in the impeller are analyzed in detail to identify the underlying physical mechanism of the effect of the tandem-impeller design on the performance of the compressor stage. Particular emphasis is placed on the evolution of the flow structure in the tandem bladed impeller by varying the inducer–exducer clocking arrangements. The results demonstrate that a tandem compressor design is more efficient than a conventional compressor design for the majority of the tested clocking configurations, and the tandem clocking friction significantly affects the impeller performance. For the tested centrifugal compressor stage, an approximately 1.4% increase in isentropic efficiency and 1.3% increase in stall margin are achieved with an inducer–exducer clocking fraction of 25%. The improvement in the primary centrifugal compressor stage performance by the tandem-impeller design is a result of the manipulation of the flow structure and the reduction in the highly distorted jet/wake exit flow pattern. Compared to the conventional impeller designs, the tandem-impeller clocking arrangement variation significantly affects the high-momentum flow along the exducer suction surface and inducer wake diffusion, inlet axial velocity, and flow angle of the exducer blade. Therefore, this variation is advantageous for shortening the length of the boundary layers on both parts of the blade and enables an intense mixing at the exducer passage to improve the flow uniformity of the impeller exit. As a result, the impeller efficiency, diffuser recovery, and stalling margin can be improved compared with the conventional design.
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Senoo, Y. "Mechanics on the Tip Clearance Loss of Impeller Blades." Journal of Turbomachinery 113, no. 4 (October 1, 1991): 680–85. http://dx.doi.org/10.1115/1.2929134.
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For predicting the tip clearance loss of turbomachines, different equations are published in the literature based on different principles. In 1986 the present author postulated a new theory where the pressure loss consisted of two parts: the pressure loss induced by the drag force of the leaked flow, and the pressure loss to support the axial pressure difference without blades in the tip clearance zone. It has been suggested that the two losses were the same loss looked from two different viewpoints, or at least apart of the former was included in the latter or vice versa. In this paper the pressure loss due to the tip clearance is examined based on a macroscopic balance of forces, and the two kinds of loss are derived. Furthermore, it is shown that the former comes from the induced drag, which is parallel to the blade, while the latter comes from the missing blade force normal to the blade in the clearance zone. Because these two forces are mutally perpendicular, the two losses are entirely different in nature and they do not even partially overlap. It is also made clear quantitatively how the loss of the kinetic energy of leaked flow is related to the induced drag of the clearance flow.
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Pan, Qiang, Weidong Shi, Desheng Zhang, BPM van Esch, and Ruijie Zhao. "Fish-friendly design of an axial flow pump impeller based on a blade strike model." Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 234, no. 2 (May 19, 2019): 173–86. http://dx.doi.org/10.1177/0957650919849768.
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With environmental awareness growing in many countries, governments are taking measures to reduce mortality of migrating fish in pumping stations. Manufacturers seek to develop pumps that are less damaging to fish and still provide good hydraulic performance, but little is known about the implications design modifications may have on internal flow characteristics and overall hydraulic performance. In this paper, an integrated design method is proposed that combines a validated blade strike model for fish damage and a computational fluid dynamics method to assess the pump performance. A redesign of an existing, conventional, axial flow pump is presented as an example in this paper. It shows how the design of the impeller blades was modified stepwise in order to reduce fish mortality while its hydraulic performance was monitored. Computational fluid dynamics analysis of the flow near the hub of the highly skewed blades indicated that unconventional design modifications were required to ensure optimum flow behavior. In the final fish-friendly design, the risk of fish mortality has reduced considerably while the hydraulic performance of the pump is still acceptable for practical application.
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Шкабура, Владимир Анатольевич. "РЕЗУЛЬТАТЫ ИССЛЕДОВАНИЙ КОМПРЕССОРНОЙ И ТУРБИННОЙ ЧАСТЕЙ ТУРБОКОМПРЕССОРОВ С ОБЩИМ РАБОЧИМ КОЛЕСОМ ДЛЯ ПРИМЕНЕНИЯ В МАЛОРАЗМЕРНЫХ ДВИГАТЕЛЯХ." Aerospace technic and technology, no. 4 (August 31, 2019): 39–43. http://dx.doi.org/10.32620/aktt.2019.4.07.
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It is considered the issues of improving small-sized engines through the application of a new type of turbomachines – turbo-compressors with general impeller (TCG) to develop engines and power plants. For example, it is shown a diagram of the simplest small-sized gas turbine engine using TCG. For the systematization of relatively efficient TCG schemes, a classification has been developed and is given in the article, of possible schemes for a turbocharger with a common impeller. The classification is based on 5 possible directions of movement of the working medium in the blade apparatus – axial (parallel to the axis of rotation of the machine), centrifugal, centripetal, diagonal and tangential. To implement one or another flowing pattern in the impeller, it is necessary to select the appropriate shape of the impeller blades and the location of the nozzle, exhaust, suction and discharge channels relative to each other. Depending on the direction of movement of the gas flows, turbo-compressors with a common impeller may have two flow patterns in interscapular impeller space – direct-flow and counter-flow. If the directions of the gas and airflow coincide concerning the axis of rotation of the impeller, then the flow pattern in the TCG is direct-flow, with opposite flow flows it is countercurrent. For carrying out the enlarged gas-dynamic calculation of TCG, formulas are given that make it possible to calculate the circumferential force arising on the blades of the impeller in the compressor and turbine working channels of the TCG. Also, formulas are given, with correction factors, for calculating the power factor of the compressor part and the load factor of the turbine part. In the process of computational and experimental studies, the characteristic of the compressor part of the TCG experimental model was obtained. The test results of the compressor part of the TCG experimental model showed good agreement between the calculated and experimental values. Studies have shown that a turbocharger with a common impeller can be used as part of small-size gas turbine engines and in a turbo-supercharging system of a small-capacity internal combustion engine with not high supercharging.
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SU, BOYANG, LEOK POH CHUA, and LIANG ZHONG. "NUMERICAL STUDIES OF AN AXIAL FLOW BLOOD PUMP WITH DIFFERENT DIFFUSER DESIGNS." Journal of Mechanics in Medicine and Biology 13, no. 03 (May 14, 2013): 1350029. http://dx.doi.org/10.1142/s0219519413500292.
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Most axial flow blood pumps basically consist of a straightener, an impeller, and a diffuser. The diffuser plays a very important role in the performance of the pump to provide an adequate pressure head and to increase the hydraulic efficiency. During the development of an axial flow blood pump, irregular flow field near the diffuser hub is not desirable as it may induce thrombosis. In order to avoid this phenomenon, two approaches were adopted. In the first approach, the number of the diffuser blades was increased from three (B3, baseline model) to five (B5 model). It was observed that the flow field was improved, but the irregular flow patterns were not completely eliminated. In the second approach, we detached the blades from the diffuser hub (B3C2 model), which was integrated and rotated with the impeller hub. It was found that the rotary diffuser hub significantly improved the flow field, especially near the diffuser hub. Besides the detailed flow fields, the hydraulic and hematologic performances at various flow conditions were also estimated using computational fluid dynamics (CFD). Although each design has its own advantages and disadvantages, the B5 model was superior based on a comparative overview.
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KIM, HWA-YOUNG, SUNG-HOON YOON, SEUNG-JAE MOON, JAE-HEON LEE, HOSEON YOO, and YUN-CHUL IM. "A STUDY ON THE FAN EFFICIENCY DECREASE ON THE BACKWARD FLOW IN AN AXIAL FAN WITH ADJUSTABLE PITCH BLADE." International Journal of Air-Conditioning and Refrigeration 18, no. 02 (June 2010): 101–7. http://dx.doi.org/10.1142/s2010132510000216.
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In this study, a numerical study has been carried out to analyze the factors of the efficiency decrease at backward flow situation in an axial fan with adjustable blades. The analysis is done with the pitch angle of 36° on the forward flow and of -26° on the backward flow. The numerical results show that the air flow rates of the pitch angle of 36° and -6° are calculated to be 285 cubic meter per min (CMM) and 212 CMM, respectively. The results are similar to the experimental results by Chang et al.1 The results had the maximum error of 10.6% compared with the experimental results. The fan efficiency decrease is caused by the fact that the axial fan used for this study was designed for the forward flow. As the results, the pitch angle of -26° has induced the recirculation around the impeller blade, impeller cover and downstream. This recirculation caused the large decrease in total pressure coefficient. This turned out to be the main cause of the efficiency decrease.
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Vanyashov, A. D., and V. V. Karabanova. "An Analysis of Spatial Nonuniformity of the Flow at the Entrance Section of the Axial-Radial Impeller of a Centrifugal Compressor Stage Working on Regulation Modes." Proceedings of Higher Educational Institutions. Маchine Building, no. 6 (711) (June 2019): 30–40. http://dx.doi.org/10.18698/0536-1044-2019-6-30-40.
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The article presents an analysis of the experimental data on testing a centrifugal compressor stage on regulation modes by changing the rotational speed of the rotor and the turning angle of the blades in the inlet guide vane unit. The distribution of the angles of attack at the entrance section of the impeller in relation to the blade height is obtained. It is established that a significant difference in the angles of attack from the plug to the periphery influences the polytropic efficiency of the compressor stage. Recommendations are given on the improvement of the mechanism of regulation by the inlet guide vane unit and on the choice of the optimum diameter for the entrance part of the driving impeller blades.
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Ye, Xuemin, Fuwei Fan, Ruixing Zhang, and Chunxi Li. "Prediction of Performance of a Variable-Pitch Axial Fan with Forward-Skewed Blades." Energies 12, no. 12 (June 19, 2019): 2353. http://dx.doi.org/10.3390/en12122353.
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For a single-stage variable-pitch axial fan, the aerodynamic performance and through flow with and without blade skewing are examined numerically. Simulated results show that the total pressure rise and efficiency increase by 2.99% and 0.16%, respectively, with the best forward-skewed angle of θ = 3° at the design conditions. At the blade pitch angles of β = 29° and 35°, the total pressure rises and efficiency of the fan with θ = 3.0° under the highest efficiency point change by −0.55%, −0.53% and 1.39%, 2.11%, respectively. At design and off-design conditions, the forward-skewed blades mitigate tip leakage and delay the emergence of separation flow at the blade root, these benefits are higher at the higher blade pitch angle. The θ = 3.0° forward skew effectively raises the stage performance of the impeller and guide vanes.
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Gu, Deyin, Xin Li, Yi Wang, Hui Xu, Mei Ye, and Li Wen. "Floating particles mixing characteristics in an eccentric stirred tank coupled with dislocated fractal impellers." International Journal of Chemical Reactor Engineering 20, no. 4 (April 1, 2022): 487–98. http://dx.doi.org/10.1515/ijcre-2021-0303.
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Abstract The mixing characteristics of floating particle dispersion process in an eccentric stirred tank with dislocated fractal impellers were investigated using computational fluid dynamics (CFD) and experimental analyses. Solid concentration distribution, axial solid concentration profile, cloud height, solid integrated velocity, power consumption and just drawdown speed were investigated. Results showed that dislocated fractal impeller can enhance solid integrated velocity and fluid turbulent fluctuation intensity compared with dislocated pitched blade impeller, and eccentric agitation coupled with dislocated fractal impeller could destroy the typical circulation loops and symmetric flow field and improve the axial circulation efficiency of floating particles on the basis of dislocated fractal impeller. Eccentric agitation coupled with dislocated fractal impeller could further enhance the floating particle dispersion homogeneity (MI) and decrease the just drawdown speed (N jd) on the basis of dislocated fractal impeller and dislocated pitched blade impeller at the specific power consumption. Meanwhile, eccentric ratio of 0.3 or 0.4 was optimal for the floating particle mixing process in this work.
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Yang, Fan, Pengcheng Chang, Wenzhu Hu, Beibei Mao, Chao Liu, and Zhongbin Li. "Numerical Study on Pressure Pulsation in a Slanted Axial-Flow Pump Device under Partial Loads." Processes 9, no. 8 (August 14, 2021): 1404. http://dx.doi.org/10.3390/pr9081404.
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The 30° slanted axial-flow pump device is widely used in agricultural irrigation and urban drainage in plains areas of China. However, during the actual operation process, the 30° slanted axial-flow pump device is prone to vibration, noise, cracks in the blades, and other phenomena that affect the safe and stable operation of the pump device. In order to analyze the flow pressure pulsation characteristics of the 30° slanted axial-flow pump device under different flow conditions, the time–frequency domain analysis method was used to analyze the pressure pulsation of each flow structure of the 30° slanted axial-flow pump device. The results showed that the internal pulsation law of the elbow oblique inlet flow channel is similar. At the 1.2 Qbep condition, the amplitude fluctuation of the pressure pulsation was small, and the main frequency is 4 times the rotating frequency. The monitoring points at the outlet of the elbow oblique inlet flow channel were affected by the impeller rotation, and the pressure pulsation amplitude was larger than that inside the elbow oblique inlet flow channel. The pressure fluctuation of each monitoring point at the inlet surface of the impeller was affected by the number of blades. There were four peaks and four valleys, and the main frequency was 4 times the rotating frequency. The amplitude of pressure fluctuation increased gradually from the hub to the rim. The main frequency of pressure fluctuation at each monitoring point of the impeller outlet surface was 4 times of the rotating frequency, and the low frequency was rich. The amplitude of pressure fluctuation was significantly lower than that of the impeller inlet. With the increase of flow rate, the peak fluctuation of pressure coefficient decreased gradually, and the amplitude of pressure fluctuation tended to be stable. Under 0.8 Qbep and 1.0 Qbep conditions, the large fluctuation of the pressure fluctuation amplitude on the outlet surface of the guide vane was mainly affected by the low-frequency fluctuation. Under the 1.2 Qbep condition, the pressure fluctuation amplitude changed periodically.
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Huang, Zongliu, Guangtai Shi, Xiaobing Liu, and Haigang Wen. "Effect of Flow Rate on Turbulence Dissipation Rate Distribution in a Multiphase Pump." Processes 9, no. 5 (May 18, 2021): 886. http://dx.doi.org/10.3390/pr9050886.
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The turbulence dissipation will cause the increment of energy loss in the multiphase pump and deteriorate the pump performance. In order to research the turbulence dissipation rate distribution characteristics in the pressurized unit of the multiphase pump, the spiral axial flow type multiphase pump is researched numerically in the present study. This research is focused on the turbulence dissipation rate distribution characteristics in the directions of inlet to outlet, hub to rim, and in the circumferential direction of the rotating impeller blades. Numerical simulation based on the RANS (Reynolds averaged Navier–Stokes equations) and the k-ω SST (Shear Stress Transport) turbulence model has been carried out. The numerical method is verified by comparing the numerical results with the experimental data. Results show that the regions of the large turbulence dissipation rate are mainly at the inlet and outlet of the rotating impeller and static impeller, while it is almost zero from the inlet to the middle of outlet in the suction surface and pressure surface of the first-stage rotating impeller blades. The turbulence dissipation rate is increased gradually from the hub to the rim of the inlet section of the first-stage rotating impeller, while it is decreased firstly and then increased on the middle and outlet sections. The turbulence dissipation rate distributes unevenly in the circumferential direction on the outlet section. The maximum value of the turbulence dissipation rate occurs at 0.9 times of the rated flow rate, while the minimum value at 1.5 times of the rated flow rate. Four turning points in the turbulence dissipation rate distribution that are the same as the number of impeller blades occur at 0.5 times the blade height at 0.9 times the rated flow rate condition. The turbulence dissipation rate distribution characteristics in the pressurized unit of the multiphase pump have been studied carefully in this paper, and the research results have an important significance for improving the performance of the multiphase pump theoretically.
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Wang, Y., S. Komori, and Z. Xu. "Design and Performance Prediction of Centrifugal Impellers." Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 210, no. 6 (December 1996): 463–76. http://dx.doi.org/10.1243/pime_proc_1996_210_073_02.
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This study presents a simple method for designing the blade geometry of a centrifugal compressor impeller. In this method, instead of giving the mean swirl distribution on the meridional surface, the blade angle distribution is specified and the blade shape is derived, making it easier to perform the design. The quasi-three-dimensional potential flow field inside the impeller is obtained using the streamline curvature method, which solves the Euler equation along arbitrary quasi-orthogonals. The viscous effect is incorporated indirectly into the inverse design of the impeller via the simplified three-dimensional boundary layer calculation and the performance prediction. A three-dimensional centrifugal impeller was designed using this inviscid-viscous method and eventually manufactured. The newly designed impeller (B) and another impeller (A) designed previously were tested on a standard apparatus for model impellers. With the aid of three-hole probes and thermocouples, the flow parameters downstream of the exit of the impellers were measured along the axial direction of the impellers. A viscous loss model related to the boundary parameters is developed and used for the performance predictions of the impellers together with other loss models. From both the boundary layer analysis and the performance prediction, it is concluded that impeller B is superior to impeller A, which is in close accordance with the measurements.
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Zhang, Li, and Ying Zi Jin. "Effect of Blade Numbers on Aerodynamic Performance and Noise of Small Axial Flow Fan." Advanced Materials Research 199-200 (February 2011): 796–800. http://dx.doi.org/10.4028/www.scientific.net/amr.199-200.796.
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To more fully explore the effect of blade numbers on aerodynamic performance and noise of small axial flow fan, some solutions are adopted to obtain the parameters’ distribution of the flow field.Firstly, the standard k-ε turbulence model is used to calculate the steady flow field of six different fan blades(such as 5,7,9,11,13,15) , and the SIMPLE algorithm is applied to couple vecolity and pressure. Secondly, the large eddy simulation in conjunction with the FH-W noise model are used to compute the unsteady flow field and noise. Finally, the experimental results verify that the calculation methods of steady flow field and unsteady flow field are correct. The conclusions show: (1)Total pressure and efficiency generally maintain the trend of firstly increasing and then decreasing with increasing the blade numbers, and it is the greatest when fan blade number is 11. The flow rate coupled with the maximum efficiency has never changed with increasing the blade numbers. (2)With the increasing blades, overall sound pressure level of the aerodynamic noise is gradually decreasing near the outlet of fan tip, while it is firstly decreasing and then increasing before decreasing again 1 meter away from the central axis of the impeller along the outlet. When fan blade number is 11, overall sound pressure level of the aerodynamic noise is the greatest.