Thematische Bibliographien / Inlet shaft

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Auswahl der wissenschaftlichen Literatur zum Thema „Inlet shaft“

Autor: Grafiati

Veröffentlicht am 28. Juni 2021

Zuletzt aktualisiert am 11. Februar 2022

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Zeitschriftenartikel zum Thema "Inlet shaft"

Yang, Qinghua, und Qian Yang. „Numerical investigation of the turbulence characteristics and energy dissipation mechanism of baffle drop shafts“. Water Science and Technology 83, Nr. 9 (07.04.2021): 2259–70. http://dx.doi.org/10.2166/wst.2021.137.

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Abstract The baffle drop shaft is widely used in deep tunnel drainage systems due to its fine applicability and high energy dissipation. To fully study the turbulence characteristics and energy dissipation mechanism of baffle drop shafts, a 1:25 scale physical model test and a numerical simulation based on the Realizable k-ε model and Volume of Fluid (VOF) method were performed. The results showed that a baffle spacing that is too dense or too sparse is not conducive to energy dissipation and discharge. The minimum baffle spacing is the optimal structural design at the design flow rate when the flow regime is free-drop flow. The energy dissipation calculation model established in this paper has high accuracy for calculating the energy dissipation rate on the baffles in free-drop flow. The energy dissipation modes of the shaft can be divided into inlet energy dissipation, baffle energy dissipation, and shaft-bottom energy dissipation. Baffles play a major role in the energy dissipation at low flow rates, and the proportions of inlet and shaft-bottom energy dissipation increase with the increase in flow rate.

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Sun, Jianchun, Heng Zhang, Muyan Huang, Qianyang Chen und Shougen Chen. „Reasonable Paths of Construction Ventilation for Large-Scale Underground Cavern Groups in Winter and Summer“. Sustainability 10, Nr. 10 (18.10.2018): 3768. http://dx.doi.org/10.3390/su10103768.

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Forced ventilation or newly built vertical shafts are mainly used to solve ventilation problems in large underground cavern groups. However, it is impossible to increase air supply due to the size restriction of the construction roadway, resulting in ventilation deterioration. Based on construction of the Jinzhou underground oil storage project, we proposed both a summer ventilation scheme and winter ventilation scheme, after upper layer excavation of the cavern is completed and connected with the shaft. A three-dimensional numerical model validated with field test data was performed to investigate air velocity and CO concentration. Fan position optimization and the influence of temperature difference on natural ventilation were discussed. The results show that CO concentration in the working area of the cavern can basically drop to a safe value of 30 mg/m3 in air inlet and exhaust schemes after 10 min of ventilation. Since there is inevitably a back-flow in the winter ventilation scheme, it is necessary to ensure that airflow is always moving towards the shaft. Optimal placement of the axial flow fan at the shaft bottom is on the central axis of the cavern, 5 m away from the shaft. The greater the temperature difference, the better the natural ventilation effect of the shaft. The natural ventilation effect of the shaft as an outlet in winter, is better than that of the shaft as an inlet in summer.

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Fernandes, João, und Ricardo Jónatas. „Experimental flow characterization in a spiral vortex drop shaft“. Water Science and Technology 80, Nr. 2 (15.07.2019): 274–81. http://dx.doi.org/10.2166/wst.2019.274.

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Abstract Connecting storm-sewers located at rather different elevations may be made with vortex drop shafts in which the energy dissipation is made by the friction between the vertical shaft and the flow and downstream by the impinging jet in a dissipation chamber. Following the first model design in the 1940s, different types of vortex drop shafts have been developed. One of the most used type is the so-called spiral vortex drop shaft developed to work in supercritical flow with good performance in both energy dissipation and space constrains. In this paper, an experimental flow characterization in a spiral vortex drop shaft is conducted covering the three main components of these structures, namely the inlet channel, the vertical shaft and the dissipation chamber. The results include measurement of water depths, pressure and velocity.

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Alpan, K., und W. W. Peng. „Suction Reverse Flow in an Axial-Flow Pump“. Journal of Fluids Engineering 113, Nr. 1 (01.03.1991): 90–97. http://dx.doi.org/10.1115/1.2926503.

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Experiments are carried out to determine the effects of different inlet geometries on the onset of suction recirculation and its associated power consumption in an axial-flow pump. The critical flow rate is determined by both the “string” visual technique and “pressure” method. The results are correlated with the inlet area and flow velocity distribution upstream of the impeller. Four different conical covers matching the impeller leading edge are employed to cover the impeller inlet completely or partially. Covering the inlet area reduces the critical flowrate corresponding to the onset of suction recirculation and eliminates all recirculation at higher flowrates. The power consumption associated with the suction recirculation flow for the uncovered impeller is determined by comparing the shaft powers with and without inlet covers. At the shut-off condition, the power is estimated from a comparison with the shaft power measured with the impeller inlet completely covered. Experimental studies conclude that the power consumption due to suction recirculation is mainly controlled by the impeller inlet area and is insensitive to the inlet pipe configuration. At shut-off condition, the power coefficient correlates well with the parameter based on the hydraulic radius of inlet area. At a finite through flowrate the analytical model recommended by Tuzson (1983) is adequate, except for a proportionality coefficient determined from the test data.

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Yao, Zhishu, Ping Zhang, Hua Cheng, Weipei Xue und Xiang Li. „Testing of a Dual-Steel-Plate-Confined High-Performance Concrete Composite Shaft Lining Structure and Its Application“. Applied Sciences 10, Nr. 8 (23.04.2020): 2938. http://dx.doi.org/10.3390/app10082938.

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To address the support problem of large-diameter drilling shafts in the west area of Zhangji coal mine, a thinner shaft lining structure composed of double layers of steel plate and high-performance concrete is proposed herein. Firstly, a series of tests of high-performance concrete preparation were carried out, and the optimized mix ratio of pumping concrete with 60–70 MPa strength for shaft lining of the drilled shaft was obtained. Then, shaft lining models were designed according to the similarity theory, and the mechanical properties of the shaft lining were experimentally studied by loading test. The test results showed that the stress state of concrete in the shaft was obviously improved, and the compressive strength of concrete was increased by 1.97–2.52 times. Finally, the results of the study were applied to a shaft in the control strata of the inlet shaft in the west area of Zhangji coal mine, which made it possible to use the drilling method to construct the shaft. The following field measurement showed that the annular strain of the shaft lining concrete was −487 με, which is far less than the ultimate strain value of C65 concrete, and the shaft lining structure was kept safe and reliable.

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Yablokov, Aleksey, Ivan Yanin, Aleksey Danilishin und Anatoliy Zuev. „Ansys CFX numerical study of stages centrifugal compressor with low-flow rate coefficient“. MATEC Web of Conferences 245 (2018): 09002. http://dx.doi.org/10.1051/matecconf/201824509002.

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The article presents results of applying the methods of computational fluid dynamics for model low-flow rate stages of centrifugal compressors with flow rate coefficient F = 0.028. The computational domain of a model centrifugal compressor for CFD-simulation consists of the following elements: inlet chamber, impeller, vaneless diffuser, return channel, outlet chamber, shaft seal labyrinth, front and back shroud leakage. Full-scale experimental studies were conducted to model stage 028 in air at an inlet pressure of p* = 1 atm. Numerical research for stage 028 held with flow rate coefficient F=(0.019-0.046) for three variants trailing edge of the impeller. According to the results of numerical research are constructed performances of stages centrifugal compressor and conducted verification of results. Estimated discrepancy between the results of numerical researches on the model with shaft seal labyrinth and without shaft seal labyrinth.

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Liu, Peng, Zheng Lin Liu, Sheng Dong Zhang, Bo Qin und Liang Zhao. „Research on Performance of Stern Shaft Mechanical Seal Based on FLUENT“. Advanced Materials Research 744 (August 2013): 31–34. http://dx.doi.org/10.4028/www.scientific.net/amr.744.31.

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Reasonable assumptions and boundary conditions, the application of CFD method of mechanical seal ring structure analysis and thermal-structural coupling analysis, research on the temperature field and the pressure field distribution of the water flim between moving and the stationary ring . Comparing the change of the maximum temperature and the water film bearing capacity though different inlet velocity and different speed under, known as the fluid inlet speed increases, the maximum temperature of the sealing water film gradually decreased, the bearing capacity gradually increased; as the stern shaft speed increases, the sealing water film maximum temperature gradually reduced, and the bearing capacity of the sealing water film is gradually increased. In this paper, the research to maintain the good performance of the stern shaft mechanical seal has important significance and role.

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Yang, Chun Xia, Meng Tian Lu, Yuan Zheng, Xiao Qing Tian und Yu Quan Zhang. „Inlet Passage’s Development and Optimization of New Tidal Unit-Shaft Tubular Turbine“. Applied Mechanics and Materials 607 (Juli 2014): 312–16. http://dx.doi.org/10.4028/www.scientific.net/amm.607.312.

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A new type of tidal unit-vertical shaft tubular turbine is designed with high efficiency, large flow rate and low water head ,which has large power under the 2~3 meters water head. According to the data of the being installed tidal units and principles of tubular turbine’s design, the high efficiency vertical shaft tubular turbine was designed under large discharge and low head, which was suitable for the tidal power station. The design also considered the requirements of turbine’s size and the details of flow through the whole flow passage were attained. The turbine’s property was predicted by the 3-d numerical simulation software on the whole flow passage. Moreover, the influences of vertical shaft’s sizes were analyzed. And the terminal of vertical shaft with or without transverse brace and longitudinal brace were analyzed to get the influence. Considering the hydraulic performance of various methods, the best guide vane opening was chosen. The results show that, the turbine unit has the best performance on efficiency, hydraulic loss, etc. with the guide vane opening 62°, meeting the power station’s design requirements. The results show that the optimal designed flow passage’s efficiency reaches up to 88.4%, the flow rate becomes much larger and the power reaches 174.63kW. Without partial vortex, the flow pattern is smooth through the whole passage also with lower hydraulic loss.

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Sanaye, Sepehr, und Salahadin Hosseini. „Off-design performance improvement of twin-shaft gas turbine by variable geometry turbine and compressor besides fuel control“. Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 234, Nr. 7 (03.12.2019): 957–80. http://dx.doi.org/10.1177/0957650919887888.

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A novel procedure for finding the optimum values of design parameters of industrial twin-shaft gas turbines at various ambient temperatures is presented here. This paper focuses on being off design due to various ambient temperatures. The gas turbine modeling is performed by applying compressor and turbine characteristic maps and using thermodynamic matching method. The gas turbine power output is selected as an objective function in optimization procedure with genetic algorithm. Design parameters are compressor inlet guide vane angle, turbine exit temperature, and power turbine inlet nozzle guide vane angle. The novel constrains in optimization are compressor surge margin and turbine blade life cycle. A trained neural network is used for life cycle estimation of high pressure (gas generator) turbine blades. Results for optimum values for nozzle guide vane/inlet guide vane (23°/27°–27°/6°) in ambient temperature range of 25–45 ℃ provided higher net power output (3–4.3%) and more secured compressor surge margin in comparison with that for gas turbines control by turbine exit temperature. Gas turbines thermal efficiency also increased from 0.09 to 0.34% (while the gas generator turbine first rotor blade creep life cycle was kept almost constant about 40,000 h). Meanwhile, the averaged values for turbine exit temperature/turbine inlet temperature changed from 831.2/1475 to 823/1471°K, respectively, which shows about 1% decrease in turbine exit temperature and 0.3% decrease in turbine inlet temperature.

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Yang, Peiji, Qi Yuan und Runlin Chen. „Experimental research on the tilting pad bearing under the high temperature of inlet oil“. Industrial Lubrication and Tribology 70, Nr. 6 (13.08.2018): 935–41. http://dx.doi.org/10.1108/ilt-01-2017-0021.

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Purpose The purpose of this study is to analyze the influence of high-temperature inlet oil on the comprehensive performance of tilting-pad bearing. Design/methodology/approach Taking a tilting-pad bearing under high temperature of inlet oil in a natural gas compressor as an example, the experimental system was developed for the tilting-pad bearing applied in a real machine, and the experiment was performed. The bearing lubricating properties under different high temperatures of inlet oil were obtained, including oil film thickness on the pivot, temperature rise and the shaft vibration values at the bearing positions. Findings The experimental results showed that the vibration, the oil film thickness on the pivot and the pad temperature were not sensitive to the change in temperature of the inlet oil, but vibrations were observed under the specific speed. At the same speed, when oil temperature changed by 1°C, the bearing temperature rise did not exceed 0.2°C and change in oil film thickness on the pivot was 1 µm. The test results of the actual unit are in good agreement with the experimental results. Originality/value The vibration measurement scheme was presented, and an indirect measurement method of fulcrum thickness was proposed. The practicability of the measurement method and the accuracy of test results were verified by the comparison of the test results of the shaft vibration, the bearing pad temperature, the fulcrum oil film thickness and the theoretical calculation results. This study will provide an important reference for designing a tilting-pad bearing with high-temperature inlet oil.

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Dissertationen zum Thema "Inlet shaft"

Dúlovcová, Gabriela. „Návrh vačkového hřídele pro motor s Millerovým cyklem“. Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2020. http://www.nusl.cz/ntk/nusl-417424.

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The main aim of this thesis is the analysis of influence of inlet valve opening length and compression ratio on performance and thermodynamic parameters of Miller cycle using GT-SUITE software. Next step was an optimization of inlet and exhaust valve timing with goal of increasing motor effective power. For chosen option was designed cam shaft with regard of kinematic and dynamic magnitude courses.

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Orme, Andrew Dallin. „Analysis of Inlet Distortion Patterns on Distortion Transfer and Generation Through a Highly Loaded Fan Stage“. BYU ScholarsArchive, 2020. https://scholarsarchive.byu.edu/etd/8649.

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Characterization of distortion transfer and generation through fans with distorted inlet conditions enables progress towards designs with improved distortion tolerance. The abruptness of transition from undistorted to distorted total pressure regions at the inlet impacts the induced swirl profile and therefore the distortion transfer and generation. These impacts are characterized using URANS simulations of PBS Rotor 4 geometry under a variety of inlet distortion profiles. A 90° and a 135° sector, both of 15% total pressure distortion, are considered. Variants of each sector size, with decreasing levels of distortion transition abruptness, are each applied to the fan. Fourier-based distortion descriptors are used to quantify levels of distortion transfer and generation at axial locations through the fan, principally at the stator inlet. It is shown that a gradual transition in distortion at the inlet results in decreased levels of distortion transfer and generation. The flow physics resulting in this reduction are explored. URANS simulations involving turbomachinery are complex and often require simplifying assumptions to balance computational costs with accuracy. One assumption removes the need for a nozzle to control nozzle operation condition and replaces it with a static pressure boundary condition located at the stator exit. This assumption is challenged by conducting a series of distorted inlet simulations with a nozzle, which are then compared to a corresponding set of simulations conducted using the exit boundary assumption. Performance parameters for each set of simulations are compared. Performance was observed to be within 1% difference between the two methods, supporting the assumption that a static pressure boundary is adequate for controlling inlet distortion simulations. Finally, full annulus URANS simulations are presented to investigate distortion phase shift in a single stage transonic fan. The fan is subject to a 90° sector inlet total pressure distortion. Simulation results are presented for choke, design, and near-stall operating conditions. Circumferential profiles of swirl, total pressure, total temperature, power, and phase shift are analyzed at 10%, 30%, 50%, 70%, and 90% span. Several metrics for phase shift, which is a measure of the rotational translation of a distortion profile, are presented and compared. Each aims to assist understanding the translational motion of distortion as it passes through the fan. The different metrics used for phase shift are used to analyze distortion phase. Insights from each are presented alongside limitations for each method. A combination of methods is proposed to address their respective limitations.

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Snee, Christopher Peter Michael. „The design and performance of a deep mine inset at North Selby mine“. Thesis, University of Newcastle Upon Tyne, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.254317.

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Shrestha, Bikram. „A Reflection Type Phase Shifter for iNET Phase Array Antenna Applications“. International Foundation for Telemetering, 2010. http://hdl.handle.net/10150/604304.

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ITC/USA 2010 Conference Proceedings / The Forty-Sixth Annual International Telemetering Conference and Technical Exhibition / October 25-28, 2010 / Town and Country Resort & Convention Center, San Diego, California
In this article we present results from modeling and simulation of a L-band reflection type phase shifter (RTPS) that provides continuous phase shift of 0° to 360°. The RTPS circuit uses a 90º hybrid coupler and two reflective load networks consisting of varactor diodes and inductors. Proper design of 90° hybrid coupler is critical in realizing maximum phase shift. The RTPS circuit implemented on a Rogers Duroid substrate is large in size. We discuss methods to reduce the size of L-band RTPS.

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Mwangi, Patricia A. W., Amr Haj-Omar und Kishan Montaque. „SIMULATION OF THE AERONAUTICAL RADIO CHANNEL FOR TELEMETRY APPLICATIONS“. International Foundation for Telemetering, 2006. http://hdl.handle.net/10150/604033.

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ITC/USA 2006 Conference Proceedings / The Forty-Second Annual International Telemetering Conference and Technical Exhibition / October 23-26, 2006 / Town and Country Resort & Convention Center, San Diego, California
The aeronautical channel is an air to ground channel characterized by multipath, high doppler shifts, Rayleigh fading and noise. Use of a channel sounder ensures proper estimation of the parameters associated with the impulse response of the channel. These estimates help us to characterize the radio channels associated with aeronautical telemetry. In order to have a satisfactory channel characterization, the amplitudes, phase shifts and delays associated with each multipath component in the channel model must be determined.

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Buchteile zum Thema "Inlet shaft"

Fais, Laura Maria Canno Ferreira, und Ana Inés Borri Genovez. „Analyses of Minimum Submergence and Air Discharge in Vertical Shafts with Different Inlets“. In Advances in Water Resources and Hydraulic Engineering, 2047–52. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-540-89465-0_351.

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„inlet shaft“. In Dictionary Geotechnical Engineering/Wörterbuch GeoTechnik, 732. Berlin, Heidelberg: Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-642-41714-6_91043.

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„shaft inlet“. In Dictionary Geotechnical Engineering/Wörterbuch GeoTechnik, 1208. Berlin, Heidelberg: Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-642-41714-6_192478.

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„inlet air shaft“. In Dictionary Geotechnical Engineering/Wörterbuch GeoTechnik, 732. Berlin, Heidelberg: Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-642-41714-6_91031.

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„inlet air shaft“. In Dictionary Geotechnical Engineering/Wörterbuch GeoTechnik, 732. Berlin, Heidelberg: Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-642-41714-6_91032.

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„air inlet shaft“. In Dictionary Geotechnical Engineering/Wörterbuch GeoTechnik, 32. Berlin, Heidelberg: Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-642-41714-6_11146.

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„shaft inset“. In Dictionary Geotechnical Engineering/Wörterbuch GeoTechnik, 1208. Berlin, Heidelberg: Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-642-41714-6_192479.

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„(shaft) inset“. In Dictionary Geotechnical Engineering/Wörterbuch GeoTechnik, 1208. Berlin, Heidelberg: Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-642-41714-6_192480.

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Konferenzberichte zum Thema "Inlet shaft"

Gasparovic, N., und J. W. Kim. „Part Load Performance of the Intercooled Two-Shaft Gas Turbine With Power Output at Constant Speed on the High-Pressure Shaft“. In ASME 1987 International Gas Turbine Conference and Exhibition. American Society of Mechanical Engineers, 1987. http://dx.doi.org/10.1115/87-gt-3.

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The general analysis of the part load performance of gas turbines indicates that the intercooled cycle with two shafts and power output at constant speed on the high-pressure shaft can have a good part load efficiency. Calculations with fixed geometry of the turbomachines show an intolerable increase of the turbine inlet temperature above the permissible level. By introducing variable geometry in the turbomachines, this disadvantage can be overcome. With variable inlet guide vanes at the high-pressure compressor an excellent part load performance is achieved. Further improvements are possible by adding an internal heat exchanger.

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Baturin, Oleg V., Daria A. Kolmakova, Alexander V. Krivtsov, Grigorii M. Popov und Andrei A. Volkov. „Estimation of the Hydraulic Losses in the Inlet Shaft of a Land-Based Gas Turbine“. In ASME 2019 Gas Turbine India Conference. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/gtindia2019-2389.

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Abstract The paper presents the results of numerical simulation of air flow through a modernized variant of the inlet filter unit (IFU) of the gas compressor unit GPA-Ts-16. A feature of the IFU design is that to reduce the load on the filter unit, it is proposed to be as compact as possible, which determines its complex shape. The goal of the study is to study the hydraulic losses and to develop the measures to reduce them, since it is found that every 100 Pa of losses in the inlet unit increases the consumption of fuel gas by 2.5 kg/h or reduces the engine power by 10.5 kW. Calculations of hydraulic losses in IFU are carried out for cases of absence or presence of wind with a velocity from 0 to 35 m/s, blowing from 5 main directions (0°, 45°, 90°, 135°, 180°). Studies are also carried out on the effect of the weather shield shape, presence of baffles under it, and the rack in the shaft on the hydraulic losses. As a result of the research, recommendations are provided for designing (changing the shape) of the inlet filter unit that eventually allow to propose a design that will reduce the hydraulic losses in IFU by 15% relative to the originally suggested variant.

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Lee, Sang Jin, Robert W. Higbee und Binxin Wu. „Impeller Placement Optimization: Mixing Versus Mechanical Shaft Fatigue“. In ASME 2014 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/imece2014-36886.

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Appropriate mixing system design is a balance between performance and cost. For most mixing systems, all flow in the mixing vessel is induced by the impeller which creates predominantly symmetrical circulatory loops and, on average, does not produce a net horizontal flow impinging against an agitator assembly. However, in some applications a fluid inlet is placed adjacent to an impeller which subjects the impeller to a continuous flow oriented perpendicular to the impeller axis of rotation. Such side flow adversely affects the life of an agitator assembly due to fatigue loading. In a particular commercial waste water treatment mixing application, there was a desire to place an impeller in a high side flow inlet region of a basin which would have necessitated an unreasonably large shaft diameter to prevent premature shaft fatigue failure. Using a combination of CFD flow analysis and fatigue based shaft design; the impeller was placed at an appropriate height to both minimize the fatigue affects of the horizontal inlet flow, as well as to ensure proper mixing. 3 separate CFD studies are presented — The originally requested configuration (impeller next to side flow), impeller situated as high in the vessel as possible (good fatigue life but poor mixing) and the final optimum configuration (acceptable fatigue life and acceptable mixing). Constant Bernoulli side flow forces were computed from time averaged constant flow velocities determined by the CFD studies which allowed the computation of mean and alternating force components whose frequency of application equaled the shaft rotations per minute. A Goodman fatigue analysis approach was utilized.

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Fujii, Akira, Shinichi Mizuno, Hironori Horiguchi und Yoshinobu Tsujimoto. „Suppression of Cavitation Instabilities by Jet Injection at Inducer Inlet“. In ASME 2005 Fluids Engineering Division Summer Meeting. ASMEDC, 2005. http://dx.doi.org/10.1115/fedsm2005-77380.

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Cavitation instabilities such as rotating cavitation and cavitation surge often occur in turbopump inducers for rocket engine. In the present study, a method for suppressing the cavitation instabilities in an inducer by jet injection is examined. Through eight nozzles placed at the upstream of the inducer, jets were injected in circumferential direction. The axial position of nozzles, speed of jet flow and direction of jet injection were changed. Through the experiments under various conditions, it was found that the occurrence regions of cavitation instabilities are decreased significantly with the injection in the same direction as shaft rotation with the jet flow rate about 10% of total flow. The flow field was also examined to clarify the mechanism for the suppression by injection. It was found that the incidence angle and cavity length were reduced by the injection, which decreases the occurrence region of instabilities.

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Xie, Rongsheng, Fangping Tang, Lijian Shi, Chuanliu Xie und Lianlian Tu. „Numerical Optimization Research on the Bidirectional Shaft Tubular Pump“. In ASME/JSME/KSME 2015 Joint Fluids Engineering Conference. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/ajkfluids2015-02758.

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The geometric parameterization model for passage inlet and outlet is solved by controlling the dimensions of each composing section, so that it will be convenient to get new model by changing the dimensions above. Base on Reynolds average N-S equations, RNG k-ε turbulent model, the hydraulic performance of bidirectional shaft tubular pumping station is simulated with the commercial CFD software. The result shows that the efficiency and the head is higher when shaft front positioned. The hydraulic loss of each part is analyzed according to the micro element method, the conclusion below can be drawn: the hydraulic loss of the shaft tubular and straight passage is small when they used for inlet passage, and mainly for frictional head loss; with the effect of circulation and spread section, the flow is easy to take off, so the hydraulic loss is lager. The hydraulic loss has a significantly reduced than the original case by adjusting the hull lines of the flow passage, The efficiency of the simulation up to 72% at positive condition, and to 57.9% at reverse condition, the efficiency of model test up to 70.4% at positive condition, and to 56.2% at reverse condition.

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Hellstrom, Fredrik, und Laszlo Fuchs. „Effects of Inlet Conditions on the Turbine Performance of a Radial Turbine“. In ASME Turbo Expo 2008: Power for Land, Sea, and Air. ASMEDC, 2008. http://dx.doi.org/10.1115/gt2008-51088.

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For a turbocharger working under internal combustion engine operating conditions, the flow will be highly pulsatile and the efficiency of the radial turbine will vary during the engine cycle. In addition to effects of the inflow unsteadiness, there is also always a substantial unsteady secondary flow component at the inlet to the turbine depending on the geometry upstream. These secondary motions may consist of swirl, Dean vortices and other cross-sectional velocity components formed in the exhaust manifold. The strength and the direction of the vortices vary in time depending on the unsteady flow in the engine exhaust manifold, the engine speed and the geometry of the manifold itself. The turbulence intensity may also vary during the engine cycle leading to a partially developed turbulent flow field. The effect of the different perturbations on the performance of a radial nozzle-less turbine is assessed and quantified by using Large Eddy Simulations. The turbine wheel is handled using a sliding mesh technique, whereby the turbine wheel, with its grid is rotating, while the turbine house and its grid are kept stationary. The turbine performance has been compared for several inflow conditions. The results show that an inflow-condition without any perturbations gives the highest shaft power output, while a turbulent flow with a strongly swirling motion at the inlet results in the lowest power output. An unexpected result is that a turbulent inflow yields a lower shaft power than a turbulent inflow with a secondary flow formed by a pair of Dean vortices. The flow field for the different cases is investigated to give a better insight into the unsteady flow field and the effects from the different inlet conditions.

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Riedmüller, Daniel, Jan Sousek und Michael Pfitzner. „Effect of Shaft Rotation, Hole and Annulus Geometry on the Discharge Behavior Through Rotating Radial Holes“. In ASME Turbo Expo 2015: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/gt2015-42044.

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This paper reports on various effects on the flow through rotating radial holes (centrifugal, centripetal) in conjunction with the geometries of hole and surrounding annuli. The aerodynamic behavior of radial rotating holes is different from the one of axial and stationary holes due to the presence of centrifugal and Coriolis forces acting in the main flow direction. Furthermore, the geometry of the inlet and outlet region is often influencing the separation behavior of the flow at the holes. To investigate the flow phenomena and the discharge behavior of these radial holes in detail, an existing test rig containing two independently rotating shafts (co- and counter rotating) was used. Experimental and numerical investigations have been performed for both flow directions through the radial holes (centripetal and centrifugal), for different hole geometries (oblong holes and round holes), inlet types (rounded and sharp), length to diameter ratios (variation of either length or diameter) and gap widths between inner and outer shaft. For each of these geometrical variations flow properties have been varied such as pressure ratio across the holes, incident Mach number and rotational speed of both shafts. To enable large parametric studies and grid independency studies an optimization model with completely automatic grid generation, CFD simulation and post-processing has been set up. As a main result of the current studies it was found, that the shaft to hole diameter is another parameter of interest for the flow behavior through shaft holes. For a centripetal flow through the shaft holes and a decreasing inner gap width, the discharge coefficient was observed to increase initially before it drops significantly. In addition, measurements of centripetal flow though oblong holes revealed higher discharge coefficient in comparison with round holes and equal length to diameter ratio.

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Novecosky, Tom. „Axial Inlet Conversion to a Centrifugal Compressor With Magnetic Bearings“. In ASME 1992 International Gas Turbine and Aeroengine Congress and Exposition. American Society of Mechanical Engineers, 1992. http://dx.doi.org/10.1115/92-gt-025.

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NOVA’s Alberta Gas Transmission Division transports natural gas via pipeline throughout the province of Alberta, Canada, exporting it to eastern Canada, United States and British Columbia. It is a continuing effort to operate the facilities and pipeline at the highest possible efficiency. One area being addressed to improve efficiency is compression of the gas. By improving compressor efficiency, fuel consumption and hence operating costs can be reduced. One method of improving compressor efficiency is by converting the compressor to an axial inlet configuration, a conversion that has been carried out more frequently in the past years. Concurrently, conventional hydrodynamic bearings have been replaced with magnetic bearings on many centrifugal compressors. This paper discusses the design and installation for converting a radial overhung unit to an axial inlet configuration, having both magnetic bearings and a thrust reducer. The thrust reducer is required to reduce axial compressor shaft loads, to a level which allows the practical installation of magnetic bearings within the space limitations of the compressor (Bear and Gibson, 1992).

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Sun, Xiaoqian, Yuanzhou Li, Longhua Hu, Ran Huo, Wanki Chow, Naikong Fong und Cheheng GiGi Lui. „One-Dimensional Smoke Movement in Vertical Open Shafts at Steady State: Theoretical Prediction and Experimental Verification“. In ASME 2008 Heat Transfer Summer Conference collocated with the Fluids Engineering, Energy Sustainability, and 3rd Energy Nanotechnology Conferences. ASMEDC, 2008. http://dx.doi.org/10.1115/ht2008-56085.

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Smoke movement in a vertical open shaft was studied by considering heat transfer to side walls and density variation due to temperature rise. Such factors used to be ignored but should be important when studying large scale upward movement of smoke in shafts with large height-to-span ratio. Steady state one-dimensional flow in the vertical direction in the shaft was theoretically described. Boussinesq approximation was not suitable in the model when the smoke temperature was high under bigger fires. The near field plume characteristics at the bottom of shaft were described based on a virtual point source assumed. The mass flow rate at the inlet level of the shaft was then calculated by using the Heskestad model. The predicted temperature rise and upward velocity were shown to both decay exponentially with height and the Nusselt number at steady state, but increased with the Reynolds number in shaft. Experiments with a 1/8 scale model were carried out to study smoke movement for different fires and were used to verify the theoretical analysis. Predicted results agreed satisfactorily with the measured values. The fire size was found to be the most important factor affecting the temperature rise and upward velocity. Buoyancy would be stronger and the hot gas thermally expanded to accelerate their upward movement.

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Simmons, Kathy, und Graham Johnson. „Velocity Measurements in the Vicinity of the Exit and Inlet of a Spiral Bevel Gear Shroud“. In ASME Turbo Expo 2015: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/gt2015-43549.

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In many aeroengines the accessory power offtake is achieved using a spiral bevel gear set running off one of the main shafts. The crown and bevel gears are housed in an internal gearbox. Over the past few years the Nottingham University Technology Centre (UTC) in Gas Turbine Transmission Systems has researched flow near spiral bevel gears both computationally and experimentally using a purpose-built test rig. In the current investigation the rig was configured with a Trent crown gear and slightly modified shroud covering the full 360° of the gear. No external containment chamber was fitted and all testing was conducted single-phase (air only) at 5,000 rpm. Laser Doppler Anemometry (LDA) was used to obtain the three components of flow velocity at a shroud exit slot and at shroud inlet. A 2D system was utilised and thus two measurements were required at each point to give the 3 velocity components. The LDA technique enabled detailed mapping of flow features over the chosen regions, which included areas very near the shroud surfaces. Data was obtained over two measurement regions: 1) a volume mapping the air “jet” exiting the shroud exit slot at top dead centre (TDC) and 2) an area capturing the flow structures local to the shroud inlet. Combined the results form an excellent set of high quality, detailed, 3-component flow data for direct use in validating CFD models and/or to define CFD boundary conditions. At the shroud exit slot the maximum velocity measured was 46.2 m/s with the jet velocity dispersing over the measurement volume such that by 26 mm from slot plane the maximum velocity was less than 20 m/s. The jet angle was found to be only 16° off perpendicular azimuthally and 22° down from perpendicular. Data from the top 5 slots shows good similarity indicating the detailed data for the TDC slot is probably applicable to all slots. Air entering the shroud comes down the shroud face and up the rotating end face of the gear shaft. The azimuthal velocity component at shroud inlet was around 20 m/s; this is of the order of 50% of the maximum linear shaft surface speed. Within 3 mm of the rotating gear face the azimuthal velocity is less than 1 m/s. Detailed measurements were obtained only at one angular location but sufficient additional measurements were obtained to determine that for the purposes of CFD validation the results can be considered representative.

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