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1
Bunt, E. A., B. Parsons i F. Holtzhausen. "Role of Dissipation Characteristics in Predicting Flow from Dissimilar Centrifugal Pumps". Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 208, nr 4 (listopad 1994): 285–94. http://dx.doi.org/10.1243/pime_proc_1994_208_049_02.
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Examination of flows in a particular case of dissimilar pumps coupled in series or in parallel (without check valves) showed that the ‘classical’ graphical solution of combined characteristics in the [+H, +Q] quadrant did not accord with the output field in certain regions. To predict the full flow fields, it was necessary to take into account dissipative flow characteristics in two other quadrants: for low-output parallel flow (when there is still flow available from the pump of higher head when the ‘weaker’ pump's flow has been reduced to zero), that in the [+H, –Q] quadrant; and for high series flow (after the output head of the pump of lower maximum flow has been reduced to zero), that in the [–H, +Q] quadrant. This problem does not arise when the pumps have identical characteristics.
2
Howey, D. A., i K. R. Pullen. "Hydraulic air pumps for low-head hydropower". Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 223, nr 2 (9.01.2009): 115–25. http://dx.doi.org/10.1243/09576509jpe645.
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Choi, Young-Do, Junichi Kurokawa i Jun Matsui. "Performance and Internal Flow Characteristics of a Very Low Specific Speed Centrifugal Pump". Journal of Fluids Engineering 128, nr 2 (5.09.2005): 341–49. http://dx.doi.org/10.1115/1.2169815.
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In very low specific speed range (ns<0.25), the efficiency of the centrifugal pump designed by the conventional method becomes remarkably low. Therefore, positive-displacement pumps have been widely used for long. However, the positive-displacement pumps remain associated with problems such as noise and vibration and they require high manufacturing precision. Since the recently used centrifugal pumps are becoming higher in rotational speed and smaller in size, there appear to be many expectations to develop a new centrifugal pump with high performance in the very low specific speed range. The purpose of this study is to investigate the internal flow characteristics and its influence on the performance of a very low specific speed centrifugal pump. The results show that large reverse flow at the semi-open impeller outlet decreases absolute tangential velocity considerably which in turn decreases the pumping head.
4
Zhang, Li, Hui Li, Hong Xu, Weidong Shi, Yang Yang, Wanhong Wang i Ling Zhou. "Experimental and Numerical Investigation of Pressure Fluctuation in a Low-Specific-Speed Centrifugal Pump with a Gap Drainage Impeller". Shock and Vibration 2021 (30.06.2021): 1–14. http://dx.doi.org/10.1155/2021/5571178.
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In order to analyze the effect of impeller with different slot widths on the performance of the low-specific-speed centrifugal pumps, based on the impeller of a single-stage pump with the specific speed of 21, two gap drainage schemes with slot widths of 1.5 mm and 6.0 mm, slot diameter of 180 mm, and lap length of 5 mm were designed. Both experimental and numerical simulation methods were applied to compare the steady performance, which includes the head, efficiency, and the internal flow field distribution, and the unsteady pressure pulsation performance between new designed pumps and the original pump. The results show that gap drainage would cause a certain degree of head reduction, but a smaller slot width could achieve higher efficiency. Meanwhile, a reasonable open seam scheme can reduce the development of pressure pulsation, which provides experience and reference for the stable operation of low-specific-speed centrifugal pumps.
5
Meakhail, T., i S. O. Park. "An improved theory for regenerative pump performance". Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 219, nr 3 (1.05.2005): 213–22. http://dx.doi.org/10.1243/095765005x7565.
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Owing to their low specific speed, regenerative pumps allow high heads with small flow rates and have performance curves with very stable features. This kind of pump is also smaller and simpler to construct than the other equivalent volumetric pumps, although it has fairly low efficiency. Over the past few years, regenerative pumps have been subject to more interest in various industrial applications. Previous mathematical models do not describe the flow characteristics very well as they are based on simplified assumptions. An improved model is proposed in this paper for the pump performance. The model can handle one inlet angle and two exit angles for the impeller blades and it can be used for the design of twisted blades that would increase the pump head and efficiency. A new feature of the pump characteristics based on the proposed model is discussed. It is shown that the proposed model yield results that are in good agreements with the experimental results. The new model also shows that the side-blade exit angle has a major effect on the performance of regenerative pump, which has not been accounted for in the previous theory.
6
Xue, Rong, Xinyi Lin, Beile Zhang, Hong Zhou, Tianwei Lai i Yu Hou. "CFD and Energy Loss Model Analysis of High-Speed Centrifugal Pump with Low Specific Speed". Applied Sciences 12, nr 15 (24.07.2022): 7435. http://dx.doi.org/10.3390/app12157435.
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High-speed centrifugal pumps with low specific speed have the characteristics of a small flowrate, a high head, and being compact and light weight, making them promising candidates for applications in the thermal management of aerospace and electronic devices. The energy loss in the low specific speed pump is critical and complex due to the large impeller diameter, the narrow and long flow channel, and the small outlet width. In this paper, an analysis method based on an energy loss model and computational fluid dynamics simulations (ELM/CFD) is proposed to analyze the performance of the low specific speed pump with a fully sealed structure. Experiments were carried out under variable water flowrates. The results show that the empirical correlation method failed to accurately predict the performance of high-speed centrifugal pumps, because the bearing clearance leakage and motor channel leakage are ignored. Moreover, the volume loss and hydraulic loss are calculated based on the empirical parameters of commonly used pumps that are different from the high-speed pump with the low specific speed in the complex flow channel structure. The ELM/CFD method calculates various loss power based on the simulation results and can predict the head and efficiency with deviations less than 2% and 5%, respectively. ELM/CFD can accurately analyze the optimization direction of the pump. The hydraulic loss and the volume loss of the impeller are the dominant factors that restrict the pump efficiency under the lower flowrates, while the hydraulic loss of subsequent flow channels becomes important under the larger flowrates.
7
Wang, Xiaohui, Junhu Yang, Zhengting Xia, Yan Hao i Xiaorui Cheng. "Effect of Velocity Slip on Head Prediction for Centrifugal Pumps as Turbines". Mathematical Problems in Engineering 2019 (24.03.2019): 1–10. http://dx.doi.org/10.1155/2019/5431047.
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The application of pumps as turbines (PAT) has been developed in several applications for energy recovery schemes. Therefore, establishing a performance correlation between pump mode and turbine mode is essential for selecting the proper machine. However, slip phenomenon is the challenges of head prediction for PAT. In this paper, the slip phenomenon of pump and PAT was revealed, and the slip factor was studied using CFD. The effect of slip on head prediction for PAT was analyzed, and a theoretical prediction model was presented considering slip factors. In order to validate the head prediction model, six centrifugal pumps with specific speed (ns) from 9 to 54.8 were tested as turbines. Results showed that the predicted head by the proposed method was in good agreement with the experimental data, and it is more accurate than Stepanoff, Alatorre-Frenk, Sharma, and Derakhshan models. This method can be applied in head prediction for low specific speed PAT ( ns <60).
8
Wan, Stephen, Jason Leong, Te Ba, Arthur Lim i Chang Wei Kang. "Numerical Characterization of the Performance of Fluid Pumps Based on a Wankel Geometry". Journal of Fluids 2014 (30.09.2014): 1–7. http://dx.doi.org/10.1155/2014/241010.
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The performance of fluid pumps based on Wankel-type geometry, taking the shape of a double-lobed limaçon, is characterized. To the authors’ knowledge, this is the first time such an attempt has been made. To this end, numerous simulations for three different pump sizes were carried out and the results were understood in terms of the usual scaling coefficients. The results show that such pumps operate as low efficiency (<30%) valveless positive displacements pumps, with pump flow-rate noticeably falling at the onset of internal leakage. Also, for such pumps, the mechanical efficiency varies linearly with the head coefficient, and, within the onset of internal leakage, the capacity coefficient holds steady even across pump efficiency. Simulation of the flow field reveals a structure rich in three-dimensional vortices even in the laminar regime, including Taylor-like counterrotating vortex pairs, pointing towards the utility of these pumps in microfluidic applications. Given the planar geometry of such pumps, their applications as microreactors and micromixers are recommended.
9
Kim, Changhyun, Semi Kim, Chang-Ho Choi i Jehyun Baek. "Effects of inducer tip clearance on the performance and flow characteristics of a pump in a turbopump". Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 231, nr 5 (2.05.2017): 398–414. http://dx.doi.org/10.1177/0957650917707656.
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A turbopump is used to pressurize propellants to gain high thrust in a projectile and consists of two pumps and a turbine. The pumps usually employ an inducer upstream to prevent performance deterioration by lowering net positive suction head required of the main impeller. However, several types of cavitation and instabilities take place in the flow field. Therefore, numerous experiments and CFD analysis for turbopumps have been conducted. Especially, there were some previous studies on inducer tip clearance, but they were limited to inducer regions due to the complexity of simulating the entire pump. In this study, the flow through an oxidizer pump in a turbopump was numerically investigated with four different sizes of inducer tip clearances. ANSYS CFX 13.0 with Rayleigh–Plesset equation was used to test flows in both non-cavitating and cavitating conditions. In the non-cavitating condition, the pump with the largest inducer tip clearance showed the worst head rise, efficiency and huge size of backflow arose near inducer casing. Also, the vortex was generated between the inducer blades in the case of large inducer tip clearance due to weak tip leakage flow. In the cavitating condition, the inducer with large tip clearance was found to be vulnerable to low suction pressure and floating cavity was observed between the inducer blades. However, the heads of the pumps with different inducer tip clearances were broken down at similar cavitation numbers due to the blade cavitation near the impeller throat. In addition, the transferred cavity from the inducer region also induced head breakdown of the pump.
10
Jiang, Linglin, Houlin Liu, Yong Wang, Yanhong Mao, Runze Zhou i Jianbin Gu. "Experimental Study on the Effect of Gas Volume Fraction on the Cavitation Performance of a Low-Specific-Speed Centrifugal Pump". Water 14, nr 5 (3.03.2022): 798. http://dx.doi.org/10.3390/w14050798.
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In order to study the cavitation performance of centrifugal pumps with low specific speeds under the condition of gas–liquid two-phase flow, a cavitation test rig for pumping gas–liquid two-phase flow was set up. The cavitation performance of the pump with a specific speed of 32 was studied. The variation of the head, pressure pulsation intensity, and vibration intensity with the cavitation allowance NPSHa (Net Positive Suction Head available) of the centrifugal pump were obtained at different inlet gas volume fraction (IGVF) conditions of 0, 1%, 2%, and 3%. The results show that the cavitation performance of a low-specific-speed centrifugal pump can be improved obviously in a certain liquid flow range when the IGVF is 1%, especially at a low liquid flow rate. When cavitation did not occur or the degree of cavitation was low, a lower IGVF can reduce pressure pulsation intensity at the pump outlet and the vibration intensity at the pump inlet under design flow rate and high flow rate conditions. Additionally, all performances of the low-specific-speed pump are more sensitive to gas when the liquid flow rate is low. The results can provide a reference for improving the cavitation performance of low-specific-speed pumps for transporting gas–liquid two-phase flow and single-phase liquids.
11
Wei, Yangyang, Yuhui Shi, Weidong Shi i Bo Pan. "Numerical Analysis and Experimental Study of Unsteady Flow Characteristics in an Ultra-Low Specific Speed Centrifugal Pump". Sustainability 14, nr 24 (16.12.2022): 16909. http://dx.doi.org/10.3390/su142416909.
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Low specific speed centrifugal pumps are widely used in urban water supply, agricultural irrigation, petrochemical and other fields due to their small flow rate and high head. Therefore, the study of unsteady flow characteristics plays a vital role in its safe and stable operation. In this paper, numerical simulation and experimental methods are used to explore the unsteady performance of the pump. The results show that the fluctuations of the external characteristic such as head, shaft power and energy loss are due to the periodic disturbance of the flow field of pump. But the transient performance of shaft power and head shows different changing trends due to different influencing factors. In this paper, the transient process of hydraulic performance is divided into three stages according to the causes and characteristics of hydraulic fluctuations. Most of the hydraulic losses occur inside the impeller, so the impeller flow field determines the level of time average hydraulic performance. Although the hydraulic loss of the spiral case is small, it is greatly affected by the rotor-stator interaction, which affects the strength of the hydraulic fluctuation. This study is of great significance to the mechanism of rotor-stator interaction and the stable operation of low specific speed centrifugal pumps.
12
Si, Qiaorui, Shouqi Yuan, Jianping Yuan, Chuan Wang i Weigang Lu. "Multiobjective Optimization of Low-Specific-Speed Multistage Pumps by Using Matrix Analysis and CFD Method". Journal of Applied Mathematics 2013 (2013): 1–10. http://dx.doi.org/10.1155/2013/136195.
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The implementation of energy-saving and emission-reduction techniques has become a worldwide consensus. Thus, special attention should be provided to the field of pump optimization. With the objective of focusing on multiobjective optimization problems in low-specific-speed pumps, 10 parameters were carefully selected in this study for anL27(310) orthogonal experiment. The parameters include the outlet width of the impeller blade, blade number, and inlet setting angle of the guide vane. The numerical calculation appropriate for forecasting the performance of multistage pumps, such as the head, efficiency, and shaft power, was analyzed. Results were obtained after calculating the two-stage flow field of the pump through computational fluid dynamics (CFD) methods. A matrix method was proposed to optimize the results of the orthographic experiment. The optimal plan was selected according to the weight of each factor. Calculated results indicate that the inlet setting angle of the guide vane influences efficiency significantly and that the outlet angle of blades has an effect on the head and shaft power. A prototype was produced with the optimal plan for testing. The efficiency rating of the prototype reached 58.61%; maximum shaft power was within the design requirements, which verifies that the proposed method is feasible for pump optimization.
13
Kesharwani, Siddhi, Kupulwng Tripura i Punit Singh. "Classical hydraulic ram pump performance in comparison with modern hydro-turbine pumps for low drive heads". Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 235, nr 6 (25.02.2021): 1463–86. http://dx.doi.org/10.1177/0957650921997202.
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We present a unique comparison of two types of renewable hydro pumping devices, namely the ram and turbine pump having different working principles. This comparison is based on experiments with these pumping devices at a field station in a village in central-east India. Our work identifies the major gaps in the study of large ram pumps, covering the hydraulic scaling conformance to creation of a unified platform for the investigation of such pumping devices with respect to operating parameters like head, flow, efficiency and, most importantly, size. The field tests of ram revealed that its non-dimensional performance parameters fit perfectly on the theoretical scaling curves. The investigations further showed that while rams had more efficiency (53–62%), they could not handle more than 40–50 l/s of discharge. In comparison, the turbine pumps, tested in laboratory conditions, were more compact for flows beyond 100 l/s, but they settled for overall efficiencies between 49% and 55%. The study recommends a limiting design flow line for rams to be 50 l/s because of the size-factor. It further finds that for absolute flows between 50 and 100 l/s within the low-head range of 3–5 meters, the design of geometrical shapes for turbine pumps could be a challenge for optimized efficiencies. The head-discharge-diameter (H-Q-D) chart developed here is a useful way of interpreting the technology with respect to boundary conditions and it creates a roadmap for future inventions in such renewable hydro-pumping devices. The paper makes a case for axial flow pumps as turbines. It concludes with a call for the propagation of research on such nature-friendly pumping technologies, where most (90–95%) of the water is returned to the stream, paving the way for a new era of sustainability.
14
Chabannes, Lilian, David Štefan i Pavel Rudolf. "Effect of Splitter Blades on Performances of a Very Low Specific Speed Pump". Energies 14, nr 13 (24.06.2021): 3785. http://dx.doi.org/10.3390/en14133785.
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The usage of splitter blades to enhance the performances of low specific speed pumps is common practice. Based on experimental and numerical studies, the influence of the addition of one and two splitter blades is investigated on a very low specific speed pump to assess their impact not only on the performance characteristics but also on the losses in all pump domains. First, the main characteristic curves are discussed and it is shown that the usage of splitter blades enhances the head of the pump while not impairing its efficiency. Secondly, a detailed analysis of the losses in the pump reveals that splitter blades improve the flow in all parts of the pumps, but the volute. The flow at the impeller outlet shows that splitter blades largely benefit the slip factor and discharges a more blade-congruent flow in the volute. However, higher absolute velocity at the outlet of the impeller with splitter blades increases friction at the volute wall, as confirmed by the average wall shear stress in the different tested cases.
15
Wang, Yuqin, Jian Luo, Shuai Liu, Zhibo Han i Xiaoqiang Ni. "Hydraulic optimization design of centrifugal pumps aiming at low vibration noise". AIP Advances 12, nr 9 (1.09.2022): 095026. http://dx.doi.org/10.1063/5.0111256.
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In order to reduce the vibration noise generated by the centrifugal pump in the working process and improve the working efficiency of the centrifugal pump, the sound field numerical calculation of IS80-65-160 single-stage single-suction centrifugal pump was carried out. Under the condition that the parameters of the pump body and the impeller remain unchanged, the number of blades of the prototype pump impeller was designed as 4, 5, 6, and 7, respectively. The flow-induced vibration and noise characteristics of centrifugal pumps were studied from two aspects of numerical simulation and test, and the renormalization group k-ε model was used to simulate the steady and unsteady state of centrifugal pumps with different blade numbers. The external characteristics, pressure pulsation characteristics, vibration, and noise of the centrifugal pump were obtained, and the flow-induced vibration and noise test platform of the centrifugal pump was built for experimental verification. The research showed that the flow induction in the model pump was the main factor affecting the vibration of the prototype pump, and the shaft frequency and blade frequency were the main reasons causing the noise of the prototype pump. The vibration of each blade was the most concentrated at onefold blade frequency, and the peak of the sound field acoustic pressure level of the pump body was higher than other frequencies at threefold blade frequency, which was most obvious in the tongue region of the volute. With the increase of blades, the noise in volute decreased. The vibration intensity of the 4-blade prototype pump was lower, but the efficiency and head were also lower. The vibration intensity of the 5-blade prototype pump was the highest, the comprehensive performance of the 6-blade prototype pump was better, and the vibration of the 7-blade prototype pump was unstable. The test results showed that six blades could effectively reduce the flow-induced vibration noise of centrifugal pumps and improve the working environment, which provided certain application value and guiding significance for the hydraulic design of the subsequent low-noise centrifugal pumps.
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Ye, Changliang, Dongsen An, Wanru Huang, Yaguang Heng i Yuan Zheng. "Investigation on Stall Characteristics of Centrifugal Pump with Guide Vanes". Water 15, nr 1 (21.12.2022): 21. http://dx.doi.org/10.3390/w15010021.
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Stall usually occurs in the hump area of the head curve, which will block the channel and aggravate the pump vibration. For centrifugal pumps with guide vanes usually have a clocking effect, the stall characteristic at different clocking positions should be focused. In this paper, the flow field of the centrifugal pump under stall conditions is numerically simulated, and the rotor–stator interaction effects of the centrifugal pump under stall conditions are studied. The double-hump characteristic is found in the head curve by using SAS (Scale Adaptive Simulation) model. The hump area close to the optimal working condition is caused by hydraulic loss, while the hump area far away from the optimal working condition point is caused by the combined action of Euler’s head and hydraulic loss. The SAS model can accurately calculate the wall friction loss, thus predicting the double-hump phenomenon. The pressure fluctuation and head characteristics at different clocking positions under stall conditions are obtained. It is found that when the guide vanes outlet in line with the volute tongue, the corresponding head is the highest, and the pressure fluctuation is the lowest. The mechanism of the clocking effect in the centrifugal pump with guide vanes is obtained by simplifying the hydrofoil. It is found that when the downstream hydrofoil leading edge is always interfered with by the upstream hydrofoil wake, the wake with low energy mixes the boundary layer with low energy, which causes small-pressure pulsation. The results could be used for the operation of centrifugal pumps with guide vanes.
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Mahkamov, K., i E. P. Orda. "Solar Thermal Water Pumps: A Preliminary Analysis of the Working Process". Journal of Solar Energy Engineering 127, nr 1 (1.02.2005): 29–36. http://dx.doi.org/10.1115/1.1767191.
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Solar thermal water pumps are low cost and low maintenance devices with a pumping capacity of 0.2-1m3/hour at a dynamic head of 1.5–5 m. The working fluid in the thermodynamic cycle is an air-steam mixture. In this paper we suggest a simple mathematical model to numerically simulate the internal processes in such a pump and determine the performance and physical dimensions of a preliminary design. The proposed mathematical model has been calibrated against experimental data and it provides the numerical simulation of the processes which occur in the cycle within an acceptable degree of accuracy for engineering purposes. The results of the analysis show that the performance of the solar water pump is mainly determined by the “steam” fraction of the cycle. The power of the solar thermal water pump increases with an increase in the maximum temperature in the cycle, while the indicated efficiency reduces because of the increase in the heat loss due to water vaporization and condensation processes.
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Ke, Qidi, i Lingfeng Tang. "Performance Optimization of Slotted Blades for Low-Specific Speed Centrifugal Pumps". Advances in Civil Engineering 2023 (5.01.2023): 1–16. http://dx.doi.org/10.1155/2023/9612947.
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Centrifugal pumps are widely used for the transport of fluids, but low-specific-speed centrifugal pumps widely have problems with serious backflow and low efficiency. In this paper, a low-specific-speed centrifugal pump with a specific speed of 55 is used as a research object. By combining numerical simulation and orthogonal experiment, the pressure distribution and velocity distribution of the flow channel are analyzed, the priority of each geometric factor for slits on pump performance is determined, the geometric parameter structure of the slotted blade is optimized by entropy weight on TOPSIS, the optimal impeller slit solution is obtained. The results show that with a balance of head and efficiency, the order of influence of the factors is: slit center width b > diameter of slit D > shrinkage ratio of slit f > depth of slit h > deflection angle of slit β . The optimal combination of slit geometry parameters is: slit center width is 3 m m , diameter of the slit is 200 m m , shrinkage ratio of the slit is 0.5, depth of the slit is 6 m m , and the deflection angle of the slit is 20°. Through ANSYS FLUENT simulation and experiment of closed pump experiment system, confirmed that hydraulic performance is improved.
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Orda, E., i K. Mahkamov. "Development of “Low-tech” Solar Thermal Water Pumps for Use in Developing Countries". Journal of Solar Energy Engineering 126, nr 2 (1.05.2004): 768–73. http://dx.doi.org/10.1115/1.1668015.
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Solar water pumps, based on electro-mechanical pumps powered by PV arrays, are commonly used and commercially available. However, one of the difficulties for their wider application in developing countries, where there is a high average insolation, is their relatively excessive cost. This arises mainly due to the high cost of the PV elements. Hence, this paper describes some developmental work and results of experimental tests on “low-tech” solar thermal water pumps which were built on the basis of Stirling engines with fluid pistons coupled to flat-plate solar collectors. Temperatures and pressures in the cycle are comparatively low, thus cheap design materials, such as glass and plastic, and a simple technology, available in the majority of mechanical workshops, can be used for their manufacture and consequently reduce their cost. Several design modifications of the above solar thermal water pumps have been developed and tested. The results obtained demonstrate that existing installations can be effectively applied for water pumping with a dynamic head which varies between 2-5 m. Furthermore, data from experimental tests shows that the pulsating motion of water in channels of the flat-plate solar collectors increases the collector’s efficiency by approximately 8-10%, which is a considerable advantage when a pump is used as part of a house solar heating system.
20
Hijikata, W., T. Mamiya, T. Shinshi i S. Takatani. "A cost-effective extracorporeal magnetically-levitated centrifugal blood pump employing a disposable magnet-free impeller". Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine 225, nr 12 (19.09.2011): 1149–57. http://dx.doi.org/10.1177/0954411911422842.
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In the field of rotary blood pumps, contactless support of the impeller by a magnetic bearing has been identified as a promising method to reduce blood damage and enhance durability. The authors developed a two-degrees-of-freedom radial controlled magnetic bearing system without a permanent magnet in the impeller in order that a low-cost disposable pump-head for an extracorporeal centrifugal blood pump could be manufactured more easily. Stable levitation and contactless rotation of the ‘magnet-free’ impeller were realized for a prototype blood-pump that made use of this magnetic bearing. The run-out of the impeller position at between 1000 r/min and 3000 r/min was less than 40 µm in the radial-controlled directions. The total power consumption of the magnetic bearing was less than 1 W at the same rotational speeds. When the pump was operated, a flow rate of 5 l/min against a head pressure of 78.66 kPa was achieved at a rotational speed of 4000 r/min, which is sufficient for extracorporeal circulation support. The proposed technology offers the advantage of low-cost mass production of disposable pump heads.
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Cheng, Wenjie, Boqin Gu i Chunlei Shao. "A numerical study on the steady flow in molten salt pump under various conditions for improved hydraulic performance". International Journal of Numerical Methods for Heat & Fluid Flow 27, nr 8 (7.08.2017): 1870–86. http://dx.doi.org/10.1108/hff-06-2016-0238.
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Purpose This paper aims to figure out the steady flow status in the molten salt pump under various temperatures and blade number conditions, and give good insight on the structure and temperature-dependent efficiencies of all pump cases. Finally, the main objective of present work is to get best working condition and blade numbers for optimized hydraulic performance. Design/methodology/approach The steady flow in the molten salt pump was studied numerically based on the three-dimensional Reynolds-Averaged Navier–Stokes equations and the standard k-ε turbulence model. Under different temperature conditions, the internal flow fields in the pumps with different blade number were systematically simulated. Besides, a quantitative backflow analysis method was proposed for further investigation. Findings With the molten salt fluid temperature, sharply increasing from 160°C to 480°C, the static pressure decreases gently in all pump cases, and seven-blades pump has the least backflow under low flow rate condition. The efficiencies of all pump cases increase slowly at low temperature (about 160 to 320°C), but there is almost no variation at high temperature, and obviously seven-blades pump has the best efficiency and head in all pump cases over the wide range of temperatures. The seven-blades pump has the best performance in all selected pump cases. Originality/value The steady flow in molten salt pumps was systematically studied under various temperature and blade number conditions for the first time. A quantitative backflow analysis method was proposed first for further investigation on the local flow status in the molten salt pump. A definition about the low velocity region in molten salt pumps was built up to account for whether the studied pump gains most energy. This method can help us to know how to improve the efficiencies of molten salt pumps.
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Si, Qiaorui, Chunhao Shen, Xiaoke He, Hao Li, Kaile Huang i Jianping Yuan. "Numerical and Experimental Study on the Flow-Induced Noise Characteristics of High-Speed Centrifugal Pumps". Applied Sciences 10, nr 9 (29.04.2020): 3105. http://dx.doi.org/10.3390/app10093105.
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The development of low-noise pumps is essential to design quiet fluid delivery systems. Due to the complicated internal flow, the flow-induced noise characteristics of high-speed centrifugal pumps have not been well understood. Taking engine cooling pumps as an example model, experimental measurements are performed in a semi-anechoic room and a CFD/CFA calculation method is proposed to study the fluid-borne noise and radiated noise characteristics. In the speed range of 5000–6750 r/min, both the pump head and the dimensionless radiated noise characteristics conform to similar laws, and the highest efficiency point pump presents the lowest noise level. Consistent with the experimental results, the predicted radiated noise of the model pump presents dipole characteristics at the required flow rate condition. Moreover, the spectrum of fluid borne noise at pump outlet shows broadband characteristics but with obvious discrete peaks, which are not only related to the fluid pressure pulsation characteristics (6f0 and the multiple) at the low-frequency region, but also to the frequency of the structural mode (3000–6000 Hz region). Rotor-stator interaction of the pump flow field between the impeller and volute is the main reason of flow-induced noise; unstable flow also contributes to the broadband components in the noise spectrum.
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Xu, Zipeng, i Huanxin Lai. "Comparison of Cavitation in Two Axial-Flow Water Jet Propulsion Pumps". Processes 11, nr 7 (17.07.2023): 2137. http://dx.doi.org/10.3390/pr11072137.
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To investigate the appropriate design method of the water jet pump, numerical simulations are carried out to compare the cavitation in two pumps designed by the streamline method and the blade load method. Based on a brief description of the design methods, the internal flow fields and cavitation in the two axial flow water jet propulsion pumps are studied by using the SST k−ω turbulence model and barotropic law cavitation model. The cavitation location, disturbance velocity field, blade load, and their variations with the cavitation number are analyzed. The results show that the pump designed by the blade load method has a smaller cavitation bubble than the pump designed by the streamline method. With the decrease of cavitation number, the vapor bubbles first appear at the blade tip of the leading edge and then extend from the leading edge to the trailing edge. The bubble thickness and the area of the low pressure on the suction surface also increases. A whirl in the disturbance velocity is observed, which turns the direction of incoming flow to the cavitation area. Furthermore, the head drop of water jet pump is related to the decrease of blade load. The results also show that at the point of cavitation number equal to 0.319, an unexpected peak of head in the pump designed by the streamline method is observed, which indicates an unstable working point for the pump. If the priorities are anti-cavitation performance and high efficiency at the design condition, the blade load method is the first choice to design pumps. While the streamline method should be adopted if high efficiency at large flow rates is preferred.
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Luo, Huican, Peijian Zhou, Lingfeng Shu, Jiegang Mou, Haisheng Zheng, Chenglong Jiang i Yantian Wang. "Energy Performance Curves Prediction of Centrifugal Pumps Based on Constrained PSO-SVR Model". Energies 15, nr 9 (1.05.2022): 3309. http://dx.doi.org/10.3390/en15093309.
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It is of great significance to predict the energy performance of centrifugal pumps for the improvement of the pump design. However, the complex internal flow always affects the performance prediction of centrifugal pumps, particularly under low-flow operating conditions. Relying on the data-fitting method, a multi-condition performance prediction method for centrifugal pumps is proposed, where the performance relationship is incorporated into the particle swarm optimization algorithm, and the prediction model is optimized by automatically meeting the performance constraints. Compared with the experimental results, the performance under multiple operating conditions is well predicted by introducing performance constraints with the mean absolute relative error (MARE) for the head, power and efficiency of 0.85%, 1.53%,1.15%, respectively. By comparing the extreme gradient boosting and support vector regression models, the support vector regression is more suitable for the prediction of performance curves. Finally, by introducing performance constraints, the proposed model demonstrates a dramatic decrease in the head, power and efficiency of MARE by 98.64%, 82.06%, and 85.33%, respectively, when compared with the BP neural network.
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Ma, Shi, i Yiou Liu. "CFD analysis and prediction of centrifugal pump cavitation performance based on three-dimensional two-phase flow between impeller and worm gear". Journal of Physics: Conference Series 2441, nr 1 (1.03.2023): 012048. http://dx.doi.org/10.1088/1742-6596/2441/1/012048.
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Abstract Cavitation performance is an important performance indicator of centrifugal pumps. The occurrence of cavitation will trigger a complex gas-liquid two-phase flow, which will reduce the efficiency of a low ratio centrifugal pump and cause machine vibration, as well as damage to the impeller, seriously affecting the working performance and preventing its normal operation. In this paper, CFD numerical simulation is used to analyze the cavitation characteristics of a centrifugal pump, obtain its internal flow law, calculate the cavitation margin of the device and the head generated by the pump under each inlet condition, and thus predict the critical cavitation margin of the pump at this flow point.
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Zhang, Fan, Martin Böhle i Shouqi Yuan. "Experimental investigation on the performance of a side channel pump under gas–liquid two-phase flow operating condition". Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 231, nr 7 (2.06.2017): 645–53. http://dx.doi.org/10.1177/0957650917713090.
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Side channel pump is a kind of small volume vane pump with low flow rate but high head and most side channel pumps can transport gas–liquid two-phase flow. In order to investigate the performance of this type of pump depending on the blade suction angle under gas–liquid two-phase flow operating condition, an experimental study has been carried out. The head and efficiency curves, and the influence of blade suction angle changes on these curves for different inlet gas volume fraction states are analyzed in detail. Moreover, the gas transporting capability of the impeller with three different blade suction angles (10°, 20°, 30°) are also compared. The results show that the head and efficiency performances of the three impellers decrease a large value when the side channel pump operates with a little gas inside, and the operating range narrows as well. With the increasing of inlet gas volume fraction, the performance of the side channel pump worsens. The head and efficiency performances in the single-phase state improve by increasing the blade suction angle, but decrease by increasing the blade suction angle in the gas–liquid two-phase flow state. The maximum gas transporting capability of the impeller with a small blade suction angle is better than a large blade suction angle. Analysis on the measured data allows a better understanding of the effect of inlet gas quantity on the performance of the side channel pump with different blade suction angles, and it could supply the design reference for two-phase flow side channel pumps.
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Elshawesh, Khaled, Khairy Agha i Elhadi Dekam. "A Mathematical Model for The Performance of Solar Heating Driven Bubble Pumps". Solar Energy and Sustainable Development Journal 7, nr 2 (31.12.2018): 13–26. http://dx.doi.org/10.51646/jsesd.v7i2.38.
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A mathematical model of the bubble pump is established by employing the governing equations; the continuity, momentum and energy equations. Th model was used to evaluate the performance of the pump under diffrent geometrical and operational conditions. Diffrent parameters including the pump tube diameter, the pumping head, and solar heating input were considered in the analysis. Th flw rates of both phases (liquid and vapor) were predicted for each set of parameters. Methanol was used as the working flid. The performance is presented for a number of diffrent scenarios. Th flw was found to be increased with both larger diameters and low static heads, while it has a roughly sine curve with the heat input. A set of results show that for a tube diameter of 10 mm and pumping head of 450 mm, increasing the heat input from 300 W to 500 W increases the mass flw rate of vapor from 0.04 kg/sec to 0.08 kg/sec, while the liquid flow increases from 0.075 kg/sec to 0.22 kg/sec, respectively. Generally, the results of this study were found to be in fair agreement with published results.
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Gao, Yi, Wei Li, Leilei Ji, Weidong Cao i Yunfei Chen. "Optimization Design of Centrifugal Pump Auxiliary Blades Based on Orthogonal Experiment and Grey Correlation Analysis". Water 15, nr 13 (5.07.2023): 2465. http://dx.doi.org/10.3390/w15132465.
Pełny tekst źródłaStreszczenie:
In order to improve the hydraulic performance of multistage centrifugal pumps through the utilization of auxiliary blades, this paper presents an optimization of these blades using orthogonal experiments and grey relational analysis. The optimization scheme for auxiliary blade structure resulted as follows: Z = 2, R = 46.9 mm, and W = 2.5. In the vicinity of the optimal operating point, the optimized scheme showed a 6% increase in head compared to the original scheme. The increase in head was not significant at low flow rates, but at high flow rates, the optimized scheme exhibited a substantial increase in head, approximately 23% higher than the original scheme. Using the L9(34) orthogonal array, the quantity (Z), inner diameter (R), and width (W) of the auxiliary blades were selected as factors, each with three levels, to design nine different impeller structures. An entire flow field numerical simulation of a five-stage centrifugal pump was conducted for the nine designs, obtaining the pump head under rated working conditions. Based on the range analysis method of orthogonal experiment, the optimal design scheme for pump head performance was derived, and the primary and secondary factors affecting the pump head were found to be the inner diameter (R), width (W), and quantity (Z) of the auxiliary blades. The accuracy of the orthogonal experimental results may have been influenced by the different factor level dimensions, and a grey relational analysis was conducted to verify the accuracy of the results, on top of the range analysis of the orthogonal experiment. A prototype was created according to the optimal solution, which under optimal conditions presented a total pump efficiency of 32.6% and a pump head of 41.39 m, significantly higher than the original design without auxiliary blades. This combination of numerical simulation with orthogonal experiments and grey relational analysis is suitable for the optimization design of auxiliary blades in multistage centrifugal pumps. This approach can accurately infer the effect of the primary and secondary factors of the geometric parameters of auxiliary blades on pump performance and their corresponding optimal solutions.
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Moifatswane, M. Prince, Nkosinathi Madushele i Noor A. Ahmed. "Improving the Performance of an Axial Flow Pump: An Overview". Advances in Science and Technology 107 (28.06.2021): 15–25. http://dx.doi.org/10.4028/www.scientific.net/ast.107.15.
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Thus far, axial flow pumps remain a significant hydrodynamic unit. These pumps have common applications for various systems that require a high flow rate and a lower head. They tend to be less efficient and consume excessive power when operating at low flow conditions. Most of the studies focus on improving the hydraulic performance of these pumps based on the best efficiency point (BEP) flow conditions. This approach is mostly based on the assumption that the pump will always operate at BEP. However, this is not always the case, because the operational condition of the pump may require an adjustment to meet certain system demands. Hence, it is necessary to emphasize the need to improve the hydraulic performance of these pumps for multiple flow conditions. This means that in addition to BEP, the lowest, and the highest operational conditions need to be considered when improving the pump performance. Also, it is important to review the phenomenon of cavitation in every design optimization investigation, given its significance to pump performance and some misrepresentation which are sometimes associated with its assessment. Therefore. the main contribution of this article is to briefly discuss the successful and unsuccessful design optimization methods of an axial flow pump. Furthermore, it highlights the significance of improving the pump performance at multiple flow conditions and also to incorporate the analysis of using CFD methods to analyze the results of cavitation performance in every pump performance improvement investigation.
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Yoon, E. S., H. W. Oh, M. K. Chung i J. S. Ha. "Performance prediction of mixed-flow pumps". Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 212, nr 2 (1.03.1998): 109–15. http://dx.doi.org/10.1243/0957650981536637.
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This paper presents the mean streamline analysis using the empirical loss models for performance prediction of mixed-flow pumps with high specific speeds. A new internal loss model to describe the effect of flow separation on the characteristic head-capacity curve with a dip in the low flow range is developed and a modified recirculation loss model for calculation of parasitic loss due to flow recirculation at the impeller exit is suggested in this study. The prediction performance of the proposed method here is tested against four sets of measured total heads and efficiencies of mixed-flow pumps, and it is also compared with that based on two-dimensional cascade theory. Predicted results by the present set of loss models agree very well with experimental data for a variety of mixed-flow pumps over the normal operating conditions.
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Marini, M., A. Massardo, A. Satta i M. Geraci. "Low Area Ratio Aircraft Fuel Jet-Pump Performances With and Without Cavitation". Journal of Fluids Engineering 114, nr 4 (1.12.1992): 626–31. http://dx.doi.org/10.1115/1.2910077.
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The experimental analysis performed on several small size low area ratio aircraft fuel jet pumps in JP4 is outlined. The variables investigated were area ratio, nozzle and throat diameters, nozzle and suction pressures. The experimental values of head ratio were compared to a one-dimensional theoretical prediction method previously found to be applicable to moderate and high area ratio pumps. The results show the necessity of making some modifications in the model at low flow coefficient values. Measured wall static pressures were also compared with the results of an axisymmetric finite difference turbulent calculation; the comparisons are generally in good agreement. The development of cavitation and related parameters were also investigated. In order to enhance cavitation resistance, which is particularly important in the field of aeronautics, some studies were carried out on two stage jet pumps. The results obtained are outlined and discussed.
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Alfian Hamsi i Tulus Burhanuddin Sitorus. "MECHANISM OF WATER DISTRIBUTION ON LEMON FARM LAND". ABDIMAS TALENTA: Jurnal Pengabdian Kepada Masyarakat 3, nr 2 (2.10.2019): 118–24. http://dx.doi.org/10.32734/abdimastalenta.v3i2.2638.
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Pump is mechanical device to increase the pressure energy of a fluid. Generaly pumps are used to lift the water from low level to high level. These are of two types,namely reciprocating pumps and centrifugal pumps. On centrifugal pumps the centrifugal force or variation of pressure due to rotation is responsible for their operation or working.
The program of community services as implementation of sciences and technology intended to introduced and give skill training about water supply units to the community at Desa Sempa jaya ,Kabupaten Deli-Karo. In this area the people have a problem about availibity of water for agricultute, when mountain Sinabung gets eruption the leave of plantation are covered with dust and damaged to citrus plants,in dry season orange plants lack of water even though the success of the harvest is very dependent on water.
The program was carried out by designing, fabricating and erecting the unit of water supply,consist of deepwell pump,piping system, valve,tee,bent,tower tank and panel control.
The result of this community services showed that the capacity of pumps are 6 liter/menit,head are 50-70 meter,power 2 HP,speed 1500 rpm.capacity of tower tank 5400 liter, the pump may supply the water to tower tank until full about 2 hours,and the farmer may use the water from the tower tank by gravitation about 3 days.
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Harisankar, O. P., Shyla Joseph, K. K. Sathian, Asha Joseph i P. R. Jayan. "Techno Economic Assessment of Axial Flow Pumps in Thrissur Kole Lands". Current Journal of Applied Science and Technology 42, nr 5 (17.03.2023): 19–28. http://dx.doi.org/10.9734/cjast/2023/v42i54068.
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Water-logged areas of wetland paddy systems must be drained in the shortest time to initiate seed bed preparation. The short time for seed bed preparation demands the adoption of low head-high discharge pumps for draining the field. A typical example of a water-logged wetland paddy system is the Kole lands lying in the Thrissur and Malappuram districts. Dewatering from these fields is mainly done by ‘petty and para’ pump, a locally made crude form of axial flow propeller pump. The petty and para pump has very low overall efficiency and requires significant installation cost and maintenance cost. Thus, as an alternative to this pump, modern axial flow pumps such as vertical submersible and vertical turbine type are gradually replacing them. At the same time, this replacement operations are capital intensive. Hence, it is necessary to assess the hydraulic and economic performance of the modern pump sets with the traditional one. Therefore, this study was conducted on the axial flow pumps in operation in the Kole lands of Thrissur District in Kerala, India, during the year 2020-2022. Performance evaluation of 50 hp petty and para pump, vertical submersible pump and vertical propeller pump was done through field pumping test and the economic analysis was carried out by considering the capital costs, operation and maintenance costs and the benefits derived from the paddy cultivation. The study revealed that overall efficiency of 50 hp petty and para pump varied from 18.51 to 22.64 percent, with a mean of 20.58 percent. In the case of vertical submersible pump, the same varied from 54.46 to 60.48 percent with a mean of 57.47 percent and in the case of propeller pump it ranged from 42.67 to 50.69 percent with a mean of 46.68 percent. It is evident that vertical submersible pump has the highest Benefit-Cost Ratio (BCR), Net Present Worth (NPW), Internal Rate of Return (IRR), and the lowest Payback Period (PP) and pumping costs among the three 50 hp axial flow pumps.
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Arifin, Samsul, Bahrul Ulum i M. Fathuddin Nur. "Experimental Test of Hydram Pump Model in Utilization of Artesian Well Water Flow". Tibuana 5, nr 01 (31.01.2022): 46–51. http://dx.doi.org/10.36456/tibuana.5.01.4959.46-51.
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A hydraulic ram is a device for moving fluid from a lower place to a higher place. Hydram pumps have the same function as pumps in general. The driving energy of the hydraulic ram pump comes from the pressure of the water entering through the suction pipe into the pump. By using the energy of a large enough flow of water at a low place, the water will flow to a higher place with less water flow capacity. The capacity of water flowing to a higher place depends on the difference in pressure between the suction pipe and the pump discharge pipe. The design of the hydraulic ram pump in the form of a model is used to distribute water sourced from artesian wells. The calculation results show that the maximum pump capacity of 2.11 x 10-4 m3/s occurs at the suction valve opening 90° and the discharge valve opening 90°, and the minimum capacity 0.51x10-4 m3/s occurs at the suction valve opening 90° and the discharge valve opening 20 °. The maximum pump head of 4.34 m occurs at 90° suction valve opening and 90° discharge valve opening, and the minimum 1.33 m pump head occurs at 90° suction valve opening and 20° discharge valve opening. The maximum water power of 0.0119 Hp occurs at 90° suction valve opening and 90° discharge valve opening, and the minimum water power occurs at 90° suction valve opening and 20° discharge valve opening.
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Yuan, Jian Ping, Yu Wen Zhu i Ai Xiang Ge. "A CFD Study on Cavitating Flow in High-Speed Centrifugal Pumps under Low Flow Rates". Advanced Materials Research 945-949 (czerwiec 2014): 914–23. http://dx.doi.org/10.4028/www.scientific.net/amr.945-949.914.
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Cavitation is one of the most important aspects that need to be considered while designing centrifugal pumps, since it is a major contributor to failure and inefficiency. In order to study the cavitating performance in high-speed centrifugal pumps under low flow rates, the pump named IN-32-32-100 with two different impellers was investigated based on numerical and experimental methods. The impeller case 1 is the impeller with six blades. The impeller case 2 is the impeller with four long and four splitter blades. The research results show that the cavities of two impellers occur at the impeller inlet. The region of developed cavities extends and the volume fraction in the blade passages gradually increases with the decrease of inlet total pressure at the flow rate of 0.5Qd. The cavities distribute asymmetrically in each blade passage and the vapor fraction of one blade passage is significantly larger compared with them of blade passages. The inner flow of the pump can be effectively improved with more uniform pressure distribution by applying splitter blades. The critical cavitation number of the impeller case 1 and impeller case 2 corresponding to the sudden head-drop point are 3.2m and 3.55m, respectively. Compared with impeller case 2, cavitating performance of the pump with impeller case 1 is better. The numerical results agree well with the experimental data, which shows that the numerical method in the present study can to some extent accurately predict the cavitating development inside the high-speed centrifugal pump.
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Nejadrajabali, J., A. Riasi i S. A. Nourbakhsh. "Flow Pattern Analysis and Performance Improvement of Regenerative Flow Pump Using Blade Geometry Modification". International Journal of Rotating Machinery 2016 (2016): 1–16. http://dx.doi.org/10.1155/2016/8628467.
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Regenerative pump is a low specific speed and rotor-dynamic turbomachine capable of developing high heads at low flow rates. In this paper, a numerical study has been carried out in order to investigate the effect of blade angle on the performance of a regenerative pump. Two groups of impellers were employed. The first type has symmetric angle blades with identical inlet/outlet angles of ±10°, ±30°, and ±50° and the second group has nonsymmetric angle blades in which the inlet angle was set to 0° and six different angles of ±10°, ±30°, and ±50° were designed for the outlet of the blades. A total of 12 impellers, as well as primary radial blades impeller, were investigated in this study. The results showed that all forward blades have higher head coefficients than radial blades impeller at design flow coefficient. It was found that regenerative pumps with symmetric angle forward blades have better performance than other types. Also, it is worth mentioning that the highest head coefficient and efficiency occur at angle+10<β<+30of symmetric angle blades. It was found that the maximum efficiency occurs at angle of +15.5° by curve fitting to the data obtained from numerical simulations for symmetric angle forward blades.
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Mandryka, A., A. P. Majid, Оleksandr Ratushnyi, Oleksandr Kulikov i D. Sukhostavets. "Ways for Improvement of Reverse Axial Pumps". Journal of Engineering Sciences 9, nr 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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Marchiori, Isabela Niedo, Gustavo Meirelles Lima, Bruno Melo Brentan i Edevar Luvizotto Junior. "Effectiveness of methods for selecting pumps as turbines to operate in water distribution networks". Water Supply 19, nr 2 (4.05.2018): 417–23. http://dx.doi.org/10.2166/ws.2018.086.
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Abstract Pressure control is an important feature for reducing leakages in water supply systems, and the use of pressure reducing valves has been well established as an efficient option for this purpose. However, several studies have demonstrated that the energy available on such sites could be used to generate electrical energy, instead of being dissipated as head loss; therefore, a more efficient and sustainable solution could be applied for pressure control. Due to the low amount of power available, the use of pumps as turbines (PATs) is highly recommended. However, manufacturers do not provide pump curves operating as turbines, making PAT selection challenging. Different empirical methods can be found in the literature for estimating PAT performance based on the pump operating conditions. Thus, this paper presents a comparative analysis of nine different methods, using real data from 14 pumps. Furthermore, the effectiveness of these methods for PAT selection is evaluated in a hypothetical network.
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Zagorodnov, V., i L. G. Thompson. "Thermal electric ice-core drills: history and new design options for intermediate-depth drilling". Annals of Glaciology 55, nr 68 (2014): 322–30. http://dx.doi.org/10.3189/2014aog68a012.
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AbstractIce coring of temperate and polythermal glaciers demonstrates some limitations of most electromechanical (EM) and thermal electric (TE) drills. Most TE drills are heavy, require a heavy power system, work slowly and cannot operate in boreholes going through the cold–temperate ice transition. Antifreeze thermal electric drills (ATED) are capable of operating in polar ice caps, polythermal and temperate glaciers, in boreholes filled with water and/or hydrophilic fluids. Performance of the ATED drill can be improved by using an open-top core barrel and low-power and narrow-kerf coring head. ATED-type drills can be modified for an open-top core barrel equipped with low-power coring head and include a new scheme for drilling-fluid circulation using two pumps. A small metering pump releases pure ethanol above the top of the drill, and a second pump enables circulation of the borehole fluid, an ethanol–water solution (EWS), above the kerf. Use of a narrow-kerf coring head reduces power requirements and makes it possible to design a lightweight drilling system that includes the EM and TE drills for shallow and intermediate-depth drilling.
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Huang, Bin, Guitao Zeng, Bo Qian, Peng Wu, Peili Shi i Dongqing Qian. "Pressure Fluctuation Reduction of a Centrifugal Pump by Blade Trailing Edge Modification". Processes 9, nr 8 (15.08.2021): 1408. http://dx.doi.org/10.3390/pr9081408.
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The pressure fluctuation inside centrifugal pumps is one of the main causes of hydro-induced vibration, especially at the blade-passing frequency and its harmonics. This paper investigates the feature of blade-passing frequency excitation in a low-specific-speed centrifugal pump in the perspective of local Euler head distribution based on CFD analysis. Meanwhile, the relation between local Euler head distribution and pressure fluctuation amplitude is observed and used to explain the mechanism of intensive pressure fluctuation. The impeller blade with ordinary trailing edge profile, which is the prototype impeller in this study, usually induces wake shedding near the impeller outlet, making the energy distribution less uniform. Because of this, the method of reducing pressure fluctuation by means of improving Euler head distribution uniformity by modifying the impeller blade trailing edge profile is proposed. The impeller blade trailing edges are trimmed in different scales, which are marked as model A, B, and C. As a result of trailing edge trimming, the impeller outlet angles at the pressure side of the prototype of model A, B, and C are 21, 18, 15, and 12 degrees, respectively. The differences in Euler head distribution and pressure fluctuation between the model impellers at nominal flow rate are investigated and analyzed. Experimental verification is also conducted to validate the CFD results. The results show that the blade trailing edge profiling on the pressure side can help reduce pressure fluctuation. The uniformity of Euler head circumferential distribution, which is directly related to the intensity of pressure fluctuation, is improved because the impeller blade outlet angle on the pressure side decreases and thus the velocity components are adjusted when the blade trailing edge profile is modified. The results of the investigation demonstrate that blade trailing edge profiling can be used in the vibration reduction of low specific impellers and in the engineering design of centrifugal pumps.
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Torabi, Rouhollah, i Seyyed Ahmad Nourbakhsh. "The Effect of Viscosity on Performance of a Low Specific Speed Centrifugal Pump". International Journal of Rotating Machinery 2016 (2016): 1–9. http://dx.doi.org/10.1155/2016/3878357.
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Centrifugal pump delivery head and flow rate drop effectively during the pumping of viscous fluids. Several methods and correlations have been developed to predict reduction rate in centrifugal pump performance when handling viscous fluids, but their results are not in very good agreement with each other. In this study, a common industrial low specific speed pump, which is extensively used in different applications, is studied. The entire pump, including impeller, volute, pipes, front and rear sidewall gaps, and balance holes, is simulated in Computational Fluid Dynamics and 3D full Navier Stokes equations are solved. CFD results are compared with experimental data such as pump performance curves, static pressure in casing, and disk friction loss. Dimensionless angular velocity and leakage rate are investigated in sidewall gap and efficiency variation due to viscosity is studied. The results demonstrate that the behavior of the fluid in sidewall gap is strictly sensitive to viscosity. Increasing viscosity improves the volumetric efficiency by reducing internal leakage through wear rings and balance holes, causing, however, a significant fall in the disk and overall efficiency. Results lead to some recommendations for designing centrifugal pumps which may be used in transferring viscous fluids.
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Si, Qiaorui, Chunhao Shen, Asad Ali, Rui Cao, Jianping Yuan i Chuan Wang. "Experimental and Numerical Study on Gas-Liquid Two-Phase Flow Behavior and Flow Induced Noise Characteristics of Radial Blade Pumps". Processes 7, nr 12 (4.12.2019): 920. http://dx.doi.org/10.3390/pr7120920.
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Miniature drainage pumps with a radial blade are widely used in situations with critical constant head and low noise requests, but the stable operation state is often broken up by the entraining gas. In order to explore the internal flow characteristics under gas–liquid two phase flow, pump performance and emitted noise measurements were processed under different working conditions. Three-dimensional numerical calculations based on the Euler inhomogeneous model and obtained experimental boundaries were carried out under different inlet air void fractions (IAVFs). A hybrid numerical method was proposed to obtain the flow-induced emitted noise characteristics. The results show there is little influence on pump characteristics when the IAVF is less than 1%. The pump head slope degradation was found to increase with air content. The bubbles adhere to the impeller hub on the blade’s suction side and spread to the periphery with a big IAVF, leading to unstable operation. It is obvious that vortices appear inside the impeller flow passage as IAVF reaches 6.5%. The two-phase flow pattern has a small effect on the characteristic frequency distribution of pressure fluctuation and emitted noise, but the corresponding pulsation intensity and noise level will increase. The study could provide some reference for low noise design of the drainage pump.
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Li, P., F. Jin, R. Tao, F. Zhang i R. Xiao. "Unsteady Simulation of the Internal Flow in a Tubular Pump Considering Tip-Leakage Flow". IOP Conference Series: Earth and Environmental Science 1037, nr 1 (1.06.2022): 012044. http://dx.doi.org/10.1088/1755-1315/1037/1/012044.
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Abstract Tip-leakage vortex is a commonly-seen phenomenon in tubular pump runners because there will be always gap between blade and pump shroud. In the operation process, the tip-leakage vortex is unstably varying. Pressure in the vortex core is relatively low and may induce cavitation in extreme conditions. The operation stability will be strongly impacted. As an effective tool, computational fluid dynamics (CFD) can be used in predicting the vortical flow in pumps. In this study, unsteady CFD simulation is conducted with the visualization of tip-leakage vortex using the Q criterion. The design-load condition is mainly studied. The temporal characters, their frequency domain features and their spatial distributions are fully analysed. This study will help understanding the tip-leakage vortical flow in the tubular pump and enhance the operation stability of low-head pumping stations.
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Skoletsky, Jennifer S., Brian T. White i Jon W. Austin. "Innovative Design to Prevent Reversal of Roller Blood Pump Rotation in the Event of Electromechanical Failure: An Easy Solution to a Devastating Problem". Journal of ExtraCorporeal Technology 39, nr 2 (czerwiec 2007): 96–98. http://dx.doi.org/10.1051/ject/200739096.
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Despite the advanced technologies of battery back-up for heart-lung consoles and the availability of system-wide generators, electromechanical failure is still occurring. Several heartlung machine manufacturers still provide unsafe handcranking devices to use in the case of an emergency while using a roller blood pump. A new design has been engineered to eliminate safety and quality issues for the perfusionist and the patient when the need for handcranking presents itself. A ratchet-style handcranking device was fabricated by means of a steel plate with adjustable pins. The adjustable pins allow for use with different models of the Cobe, Stockert, and Jostra heart-lung consoles, which contain roller pumps with 180° roller heads. Additional modifications such as a 1:2 transmission and fluorescent markers are also used in the design. This innovative design is an improvement in safety compared with the current handcrank provided by Cobe, Stockert, and Jostra. With this modified handcranking device, accidental reverse rotation of the roller pump head cannot occur. Fluorescent markers will improve visualization of the pump head in low-light situations. The ergonomic design improves efficiency by reducing fatigue. Most importantly, a “safe” safety device will replace the current design provided by these manufacturers, thus improving the quality of care by health care providers.
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Li, Chenhao, Xingqi Luo, Jianjun Feng, Guojun Zhu i Yangang Xue. "Effects of Gas-Volume Fractions on the External Characteristics and Pressure Fluctuation of a Multistage Mixed-Transport Pump". Applied Sciences 10, nr 2 (13.01.2020): 582. http://dx.doi.org/10.3390/app10020582.
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In the petroleum industry, multiphase transport pumps are a crucial technology for petroleum extraction. Therefore, the pressure fluctuation and internal-flow characteristics of multiphase transport pumps with different inlet-gas-volume fractions (IGVFs) have become an important research topic. Studying the pressure fluctuation and its effects on the performance of mixed-transport pumps under different IGVFs is significant for improving the running stability of pumps. In this work, steady and transient flow with different IGVFs was solved using the Navier–Stokes equation applied to a structured grid and the Shear Stress Transport (SST) turbulence model. The effects of IGVFs on the pressure pulsation and the performance of a three-stage, mixed-transport pump were studied. Results indicated that the numerical calculation results agreed well with the experimental data. The numerical method could predict the gas and liquid two-phase flow in the mixed-transport pump accurately. The pressure increase of this pump decreased with the increased flow quantity and the IGVFs. The efficiency improvement of the pump was limited by the increasing the flow rate. Under the rated-flow condition, a quantitative relationship was established between the relative discharge of the IGVF and the decrease in the pump head; when the IGVF exceeded 15%, the pressurization capacity decreased by more than 30%. Along the blade centerline direction, the pressure fluctuation amplitude near the suction surface of the impeller blade head gradually increased. Numerical simulation results showed that the dominant frequency of the pressure fluctuation of the impeller and diffuser was ten and seven times that of the rotation frequency, respectively. Thus, the IGVFs greatly influenced the dominant frequency of the pressure fluctuation. The air in the impeller primarily piled up at the suction surface of the blade head near the front cover. Under a centrifugal force, water was pushed to the back cover plate, making the gas-volume fraction near the front cover plate higher. Consequently, the distribution of gas content in the impeller became uneven. On the blade suction surface near the front cover plate, a low-velocity area caused by flow separation was generated, which further affected the pressure pulsation in the impeller. There were obvious vortices in the diffuser, and the vortex position had a tendency to move toward the inlet of the diffuser with an increased gas content. The flow pattern in the impeller was consistent, which indicated the great transport performance of this pump. In conclusion, through numerical simulation and experimental research, this study revealed the effects of the IGVFs on the performance and pressure pulsation of a mixed-transport pump under a gas–liquid two-phase flow condition. Our findings may serve as a guide for the optimization of a multiphase pump.
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Audisio, Orlando Anibal, Mariano Nicolás Rossi i Paul José Alonso. "Experimental study of a centrifugal pump operating as a hydraulic turbine". +Ingenio, Ene - Jun 2022 V4 N1 (12.12.2022): 68–81. http://dx.doi.org/10.36995/j.masingenio.2022.12.12.006.
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An experimental investigation of centrifugal pump has been carried out to study its characteristics in pump and turbine mode operation (PAT). The correlation between pump and PAT performance is a major problem. Several methods have been developed to predict the best efficiency of pumps running as turbines, but their results are not in good coincidence with experimental data for all pumps. Fluid dynamic behavior of PAT changes appreciably, in relation to its localized and distributed hydraulic losses, velocity profiles and pressures at homologous points. It is not possible to infer the behavior of a PAT using similarity parameters from pump mode performance; very large errors are made. This paper presents the experimental parameters of the operating of a PAT with specific number low. In order to determine the pump’s characteristic as turbine, we used a closed-circuit experimental setup in which the admission pressure head was realized with another pump and the correlation between the diameter of the PAT and the specific number for three different ranges of flow was determined. This is based on an experimental database on a centrifugal pump of specific number 17 .80 [RPM, m3 /s, m] in bothrotation modes and for a speed range of rotation between 250 and 2500 RPM. All required parameters were measured to achieve complete characteristic curves of the reverse pump. The functional characterization showed curves of the hydraulic machine in the turbine mode with variation of operating parameters, such as rotation speeds, heights, and flow rates. With the results obtained, the comparatives made allowed observing the influence of these variations on the performance of the PATs. Curves obtained allowed inferring the behavior in turbine mode from pump mode parameters. Values obtained from the derived correlations showed good match with experimental results.
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Uralov, Bakhtiyor, Shukhrat Mutalov, Bakhtiyar Shakirov, Gulnoza Khakimova, Burkhon Sirojov i Iqboloy Raimova. "Influence of hydroabrasive wear of impeller blades on head of centrifugal pump". E3S Web of Conferences 365 (2023): 03012. http://dx.doi.org/10.1051/e3sconf/202336503012.
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The results of experiments on studying the nature of changes in the concentration and dispersion of solid suspended particles showed that the highest average monthly sediment concentration is 2.5...3.8 kg/m3, and sometimes in rainy weather, the maximum water turbidity reaches 7kg/m3. In the composition of solid mechanical impurities, a significant amount consists of particles with a grain size of 0.1-0.05mm. Observations have established that particles larger than 0.01 mm at a low flow velocity in the supply channel and the water intake chamber of the pumping station were easily deposited in them. Siltation volumes at various stations ranged from 20 to 60%. As a result, the hydraulic resistance increased, which led to a decrease in the pump head. The wear of parts of centrifugal pumps in natural conditions was also studied, and the dependences of wear on the characteristic dimensions and duration of their operation are given. The results of micrometering of the working parts of the pumps showed that the blades of the impellers along the length and width wear out unevenly both in size and shape. This is explained by the fact that when the hydroabrasive flow moves in the interblade space, the kinetic energy of solid particles and their local concentration increase due to an increase in the values of centrifugal and Coriolis forces along the radius of the impeller.
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Han, Chen, Junze Liu, Yang Yang i Xionghuan Chen. "Influence of Blade Exit Angle on the Performance and Internal Flow Pattern of a High-Speed Electric Submersible Pump". Water 15, nr 15 (31.07.2023): 2774. http://dx.doi.org/10.3390/w15152774.
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The impeller vane exit placement angle has a critical role in the flow characteristics of the fluid inside the lobe, thus having a profound effect on the overall pump performance. The purpose of this study is to investigate the effect of the impeller exit angle on the operating characteristics of a high-speed well submersible pump, and the numerical calculation results of the original model are in good agreement with the experimental results. In this paper, five different impeller vane exit angles, namely 10°, 15°, 20°, 25° and 30°, are selected for numerical analysis based on the original model, and the flow conditions of 0.6 Q, 1.0 Q and 1.4 Q are analyzed for each angle. The results show that the impeller vane exit placement angle not only affects the static pressure distribution, velocity distribution and streamline distribution within the impeller and guide vane, but also has a significant effect on the head curve, power curve and efficiency curve of the well submersible pump. As the flow slip inside the impeller of high-speed well submersible pumps intensifies, the large impeller outlet angle will cause the power of the impeller to increase linearly with the flow rate, thus reducing the pump efficiency. In the low-flow and high-flow conditions, a small outlet angle of 10° will make the efficiency of high-speed submersible pumps higher than in other conditions, and these findings can provide some reference for the optimal design of high-speed submersible pumps.
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Zhang, Yu-Liang, i Wen-Guang Li. "An analytical method for determining the optimum number of blades of the compound impeller in a low specific speed centrifugal pump". Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering 234, nr 6 (21.06.2020): 576–87. http://dx.doi.org/10.1177/0954408920934665.
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Reasonable methods for determining the optimum number of blades in a low specific speed centrifugal pump with closed-type impeller with splitters, i.e. compound impeller have been rather rare in the literature so far. In the article, a new analytical method was put forward to determine such an optimum number of blades by including the effect of turbulent boundary layer over impeller blades. Three conventional impellers with different numbers of full-length blades and two compound impellers with different numbers of splitters were designed and manufactured. The corresponding performance tests were then conducted. Results showed that the optimum numbers of blades exist for two kinds of impeller in terms of head at design point, pump efficiencies at design point and best efficiency point, and slope of head-flow rate curve at shut-off point. The estimated optimum numbers of blades are in good agreement with the numbers based on the experiments. The conventional impellers with full-length blades are more prone to the hump phenomenon than the compound impellers at the optimum numbers of blades. For the compound impellers, however, the hump effect is negligible at the optimum number of blades, and their head and efficiency are higher than those for the impellers with full-length blades. The method is applicable to compound impeller design in low specific speed centrifugal pumps.
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Song, Wen-wu, Li-chao Wei, Jie Fu, Jian-wei Shi, Xiu-xin Yang i Qian-yu Xu. "Analysis and control of flow at suction connection in high-speed centrifugal pump". Advances in Mechanical Engineering 9, nr 1 (styczeń 2017): 168781401668529. http://dx.doi.org/10.1177/1687814016685293.
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The backflow vortexes at the suction connection in high-speed centrifugal pumps have negative effect on the flow field. Setting an orifice plate in front of the inducer is able to decrease the negative effect caused by backflow vortexes. The traditional plate is able to partially control the backflow vortexes, but a small part of the vortex is still in the inlet and the inducer. Four new types of orifice plates were created, and the control effects on backflow vortexes were analyzed. The ANSYS-CFX software was used to numerically simulate a high-speed centrifugal pump. The variations of streamline and velocity vectors at the suction connection were analyzed. Meanwhile, the effects of these plates on the impeller pressure and the internal flow field of the inducer were analyzed. Numerically, simulation and experimental data analysis methods were used to compare the head and efficiency of the high-speed pumps. The results show that the C-type orifice plate can improve the backflow vortex, reduce the low-pressure area, and improve the hydraulic performance of the high-speed pump.