Academic literature on the topic 'Impeller discharge flow coefficient'

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Journal articles on the topic "Impeller discharge flow coefficient"

1

Arndt, N., A. J. Acosta, C. E. Brennen, and T. K. Caughey. "Experimental Investigation of Rotor-Stator Interaction in a Centrifugal Pump With Several Vaned Diffusers." Journal of Turbomachinery 112, no. 1 (January 1, 1990): 98–108. http://dx.doi.org/10.1115/1.2927428.

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This paper describes an experimental investigation of rotor-stator interaction in a centrifugal pump with several vaned diffusers. Steady and unsteady diffuser vane pressure measurements were made for a two-dimensional test impeller. Unsteady impeller blade pressure measurements were made for a second two-dimensional impeller with blade number and blade geometry identical to the two-dimensional impeller used for the diffuser vane pressure measurements. The experiments were conducted for different flow coefficients and different radial gaps between the impeller blade trailing edge and the diffuser vane leading edge (5 and 8 percent of the impeller discharge radius). The largest pressure fluctuations on the diffuser vanes and the impeller blades were found to be of the same order of magnitude as the total pressure rise across the pump. The largest pressure fluctuations on the diffuser vanes were observed to occur on the suction side of the vane near the vane leading edge, whereas on the impeller blades the largest fluctuations were observed to occur at the blade trailing edge. However, the dependence of the fluctuations on the flow coefficient was found to be different for the diffuser vanes and the impeller blades; on the vane suction side, the fluctuations were largest for the maximum flow coefficient and decreased with decreasing flow coefficient, whereas at the blade trailing edge, the fluctuations were smallest for the maximum flow coefficient and increased with decreasing flow coefficient. Increasing the number of the diffuser vanes resulted in a significant decrease of the impeller blade pressure fluctuations. The resulting lift on the diffuser vanes was computed from the vane pressure measurements; the magnitude of the fluctuating lift was found to be larger than the steady lift.
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Childs, D. W. "Pressure Oscillation in the Leakage Annulus Between a Shrouded Impeller and Its Housing Due to Impeller-Discharge-Pressure Disturbances." Journal of Fluids Engineering 114, no. 1 (March 1, 1992): 61–67. http://dx.doi.org/10.1115/1.2910001.

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An analysis is presented for the perturbed flow in the leakage path between a shrouded-pump impeller and its housing caused by oscillations in the impeller-discharge pressure. A bulk-flow model is used for the analysis consisting of the path-momentum, circumferential-momentum, and continuing equations. Shear stress at the impeller and housing surfaces are modeled according to Hirs’ turbulent lubrication model. In the present analysis, perturbations of the impeller discharge pressure are used to excite the fluid annulus. The circumferential variation of the discharge pressure is expanded in a Fourier series up to order n1, where n1 is the number of impeller blades. A precession of the impeller wave pattern in the same direction or opposite to pump rotation is then assumed to completely define the disturbance excitation. Predictions show that the first (lowest-frequency) “centrifugal-acceleration” mode of the fluid within the annulus has its peak pressure amplitude near the wearing-ring seal. Pressure oscillations from the impeller can either be attenuated or (sharply) magnified depending on: (a) the tangential velocity ratio of the fluid entering the seal, (b) the order of the fourier coefficient, and (c) the closeness of the precessional frequency of the rotating pressure field to the first natural frequency of the fluid annulus, and (d) the clearance in the wearing-ring seal.
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3

Zhang, Wenwu, Zhiyi Yu, and Yongjiang Li. "Analysis of flow and phase interaction characteristics in a gas-liquid two-phase pump." Oil & Gas Science and Technology – Revue d’IFP Energies nouvelles 73 (2018): 69. http://dx.doi.org/10.2516/ogst/2018072.

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To analyze the characteristics of internal flow and phase interaction in a gas-liquid two-phase pump, the influence of Inlet Gas Void Fraction (IGVF), discharge coefficient, and medium viscosity were investigated using medium combinations of air-water and air-crude. Simulations were performed using ANSYS_CFX at different IGVFs and various values of discharge coefficient. Structured grid for the full flow passage was generated using ICEM_CFD and TurboGrid. Under conditions of IGVF = 0% (pure water) and IGVF = 15%, the reliability of numerical method was proved by means of the comparison with the experimental data of external characteristic. The results for air-water combination showed a uniform gas distribution in the inlet pipe, and formation of a stratified structure in the outlet pipe. The gas in impeller gathered at the hub because of the rotation of the impeller, also, the interphase forces increased with the increased IGVF. For the two medium combinations, the drag force was the largest interphase force, followed by added mass and lift forces, and then the turbulent dispersion force was the least, which can be neglected. Because of the larger viscosity of crude than that of water, the variation trend of interphase forces in the impeller is relatively smooth along the flow direction when the medium combination was air-crude.
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Uy, Robert V., and Christopher E. Brennen. "Experimental Measurements of Rotordynamic Forces Caused by Front Shroud Pump Leakage." Journal of Fluids Engineering 121, no. 3 (September 1, 1999): 633–37. http://dx.doi.org/10.1115/1.2823516.

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Unsteady forces generated by fluid flow through the impeller shroud leakage path of a centrifugal pump were investigated. Different pump shroud geometries were compared, and the effect of leakage path inlet swirl (pump discharge swirl) on the rotordynamic forces was examined for various ratios of fluid throughflow velocity to impeller tip speed. A short axial length leakage path reduced the measured forces, while curvature appeared to increase the destabilizing forces when inlet swirl was present. It was observed that changing the inlet swirl velocity does not appear to significantly affect the measured forces for a given leakage flow coefficient, but any nonzero inlet swirl is destabilizing when compared to cases with no inlet swirl.
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Pei, Ji, Wenjie Wang, Shouqi Yuan, and Jieyun Mao. "Numerical Investigation of Periodically Unsteady Pressure Field in a High Power Centrifugal Diffuser Pump." Advances in Mechanical Engineering 6 (January 1, 2014): 159380. http://dx.doi.org/10.1155/2014/159380.

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Pressure fluctuations are the main factors that can give rise to reliability problems in centrifugal pumps. The periodically unsteady pressure characteristics caused by rotor-stator interaction have been investigated by CFD calculation in a residual heat removal pump. Side chamber flow effect is also considered for the simulation to accurately predict the flow in whole flow passage. The pressure fluctuation results in time and frequency domains were considered for several typical monitoring points in impeller and diffuser channels. In addition, the pressure fluctuation intensity coefficient (PFIC) based on standard deviation was defined on each grid node for entire space and impeller revolution period. The results show that strong pressure fluctuation intensity can be found in the gap between impeller and diffuser. As a source, the fluctuation can spread to the upstream and downstream flow channels as well as the side chamber channels. Meanwhile, strong pressure fluctuation intensity can be found in the discharge tube of the circular casing. In addition, the obvious influence of operational flow rate on the PFIC distribution can be found. The analysis indicates that the pressure fluctuations in the aspects of both frequency and intensity can be used to comprehensively evaluate the unsteady pressure characteristics in centrifugal pumps.
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Baskharone, E. A., A. S. Daniel, and S. J. Hensel. "Rotordynamic Effects of the Shroud-to-Housing Leakage Flow in Centrifugal Pumps." Journal of Fluids Engineering 116, no. 3 (September 1, 1994): 558–63. http://dx.doi.org/10.1115/1.2910313.

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The fluid/shroud interaction forces acting on a pump impeller that is precessing around the housing centerline, are computed and the rotordynamic coefficients deduced. The numerical procedure utilized is an upgraded version of a finite-element-based perturbation model, initially devised for simple see-through annular seals. The computational model accounts for the complex flow structure in the shroud-to-housing secondary flow passage, which includes a tight-clearance face seal. The model also facilitates the mutual interaction between the primary and secondary flows near the impeller inlet and discharge stations. The numerical results are compared to existing experimental data, as well as the results of a simpler and widely used numerical model. Sources of discrepancies between the numerical results are identified, and a comprehensive assessment made in light of the experimental data.
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Yu, Zhiyi, Wenwu Zhang, Baoshan Zhu, and Yongjiang Li. "Numerical analysis for the effect of tip clearance in a low specific speed mixed-flow pump." Advances in Mechanical Engineering 11, no. 3 (March 2019): 168781401983222. http://dx.doi.org/10.1177/1687814019832222.

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To study the influence of tip clearance on performance (external characteristics, pressure fluctuation and tip loss) of a low specific speed mixed-flow pump, unsteady simulation was performed for the whole flow passage with five tip clearance sizes ( δ0 = 0 mm, δ1 = 0.10 mm, δ2 = 0.25 mm, δ3 = 0.75 mm and δ4 = 1 mm). The reliability of the numerical methodology was verified in external characteristics (efficiency, head and power) and fluctuation. The performance of the pump was obtained under different discharges and tip clearance sizes using ANSYS CFX. The results showed that the variation of tip clearance size has greater effect on the external characteristics under large discharges. Meanwhile, along the flow direction, the fluctuation coefficients near the impeller shroud increase gradually with the smaller tip clearance sizes ( δ = 0.10 and 0.25 mm), while for the larger tip clearance sizes ( δ = 0.75 and 1.00 mm), the significant increase of fluctuation near the shroud of impeller inlet is closely associated with the clear leakage vortex and the large region of low pressure. Besides, with the increase of tip clearance size, the effect of tip clearance will become more remarkable under different discharge conditions. According to this study, for the optimization design of such pumps, the size of the tip clearance is suggested to be about 0.9% times the blade height at middle of the impeller passage.
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Hernández Ramírez, Gabriel, Ángel Manuel León Segovia, Edison Salazar, Roberto Beltran Reina, and Julio Cesar Pino Tarragó. "Mathematical modeling of the coefficient of load correction of the pumping of hydromixtures lateritic." DYNA 86, no. 208 (January 1, 2019): 19–27. http://dx.doi.org/10.15446/dyna.v86n208.72006.

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The purpose of the present investigation was to determine the behavior correction coefficient of the characteristics of the centrifugal pump load curves, using mathematical models, taking into account the rheological properties. From experimental studies such as X-ray diffraction, X-ray fluorescence, particle size analyzer, rheological analysis and mathematical modeling we obtain the behaviors of the physical and chemical interactions that take place in non-Newtonian fluids. It is concluded that to obtain a mathematical model of the correction coefficient and the equations describing the behavior of the characteristic load - discharge curves of the networks and of the pumps to, by means of the joint analysis of these, obtain the frequency of rotation of the impeller that guarantees the required flow rates in energy efficient operating regimes.
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Li, Yuan, Hua Chen, Xiangjun Li, Minghe Jiang, and Guinian Wang. "Influence of U-tube type casing treatment on pressure fluctuations of a centrifugal pump at low flow conditions." Modern Physics Letters B 35, no. 12 (March 9, 2021): 2150205. http://dx.doi.org/10.1142/s0217984921502055.

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The existence of pressure pulsations greatly increases the vibration and noise of pumps and harms their service life. In this paper, a casing treatment was employed to explore its impact on the pressure pulsations. A U-tube type groove was created at the inlet end-wall of a centrifugal pump and front cover of the impeller to connect the impeller with the inlet pipe by passing impeller leading edge. An unsteady numerical investigation was launched of the pump with and without this casing treatment, to study its influence on the pressure pulsations inside the pump and the mechanisms behind. The numerical results of the pump without casing treatment was first compared with the test performance of the pump to validate the numerical method, and gave excellent agreements with the test results. The CFD results also showed that the casing treatment increases the head coefficient and efficiency of the pump. Pressure pulsations at a reduced mass flow condition were studied by monitoring unsteady pressure signals generated by the CFD at various locations inside the pump. A Fast Fourier transform (FFT) was performed on the signals. The pump employs a double tongues volute with each tongue covering 180[Formula: see text] circumference. However, the two tongues are not identical with regard to the discharge of the pump. These geometric features of the volute and the pump’s operating condition generate several pressure pulsations in the frequencies of [Formula: see text], [Formula: see text], [Formula: see text] in the original pump. Due to the circumferential unifying capability of the casing treatment and its improvement to the impeller flow, these pulsations at impeller inlet are weakened or disappear when the U-tube is present. The pressure pulsation inside the impeller is less affected by the treatment. The [Formula: see text] pulsation at volute tongues also decreases or disappears for the same reasons, but [Formula: see text] pulsation increases slightly and this is due to the improved pressure recovery in the volute by the treatment which increases the pressure difference across one of the volute tongues. The unsteady radial force of the impeller exerting on journal bearings becomes more uniform and smaller when the casing treatment is employed.
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Arndt, N., A. J. Acosta, C. E. Brennen, and T. K. Caughey. "Rotor–Stator Interaction in a Diffuser Pump." Journal of Turbomachinery 111, no. 3 (July 1, 1989): 213–21. http://dx.doi.org/10.1115/1.3262258.

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The interaction between impeller blades and diffuser vanes in a diffuser pump was investigated. Steady and unsteady pressure measurements were taken on the diffuser vanes, and the shroud wall of a vaned and a vaneless diffuser. Steady, unsteady, and ensemble-averaged unsteady data, as well as frequency spectra, are presented. The measurements were made for different flow coefficients, shaft speeds, and radial gaps between impeller blade trailing and diffuser vane leading edge (1.5 and 4.5 percent based on impeller discharge radius). The resulting lift on the vane, both steady and unsteady, was computed from the pressure measurements at midvane height. The magnitude of the fluctuating lift was found to be greater than the steady lift. The pressure fluctuations were larger on the suction side than on the pressure side attaining their maximum value, of the same order of magnitude as the total pressure rise across the pump, near the leading edge. Pressure fluctuations were also measured across the span of the vane, and those near the shroud were significantly smaller than those near the hub. The pressure fluctuations on the shroud wall itself were larger for the vaned diffuser than a vaneless diffuser. Lift, vane pressure, and shroud wall pressure fluctuations decreased strongly with increasing radial gap.
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Dissertations / Theses on the topic "Impeller discharge flow coefficient"

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Duda, Petr. "Optimalizace polohy propelerové turbíny v kašně." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2014. http://www.nusl.cz/ntk/nusl-231499.

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The thesis contains basic information about propeler turbines. It deals with the correct location in the fountain so as to ensure the highest possible performance. Part of the work is devoted to the all-weather resulting blade to blade channels and their impact on the room is filled with diffuser.
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Yu, Ziyun. "Fluid and suspension hydrodynamics in the impeller discharge flow of stirred tanks." Doctoral thesis, KTH, Chemical Engineering and Technology, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3813.

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The hydrodynamics of an agitated tank have been studied byphase-Doppler anemometry. The focus is on the impeller anddischarge region of a 45o pitched blade turbine (PBT). Thestudy includes agitation of pure water as well as of a dilutesuspension of process particles. A three-dimensionalphase-Doppler anemometer is used to measure local,instantaneous, three-dimensional velocities of the fluid and ofthe suspended particles. A shaft encoding technique is used toresolve the turbulent fluctuations from the periodic velocityfluctuation due to the impeller blades, and to provide moredetailed information about the variations relative to theimpeller blade. Velocity bias is corrected for by the total3-dimensional velocity.

The mean flow field, the fluctuating velocities, and thecomplete Reynolds stress tensor, are reported for the liquidphase flow. The periodic fluctuations in the flow that aregenerated by the impeller blades are eliminated in theexamination of the turbulence. The anisotropy of the turbulenceis assessed by the invariants of the anisotropy tensor. Thetrailing vortex structure is demonstrated to be associated withhigh kinetic energy and strong anisotropy of the turbulence.The vortex is still observable 130-140 degrees behind theblade. It gradually moves down from the impeller blade but thelocation in radial direction remains essentially unchanged. Theinfluence of the periodic fluctuations is examined and it isshown that the turbulence appears more isotropic when theperiodic fluctuations are not eliminated.

The solid particle concentration is low below the impellerand is high above the impeller tip. The particles diverge fromthe liquid flow mean direction, especially below the agitatorclose to the tip where the strongest turbulence is found.Periodic fluctuations in the particle concentration relate tothe variations found in the angle-resolved mean velocity andfluctuating velocity. The ratio of the maximum to the minimumconcentration is about 2.0 in the present study.

The baffles influence on the conditions in the impellerregion, and this influence can be observed on the fluid meanvelocity field, the angle-resolved velocities, the kineticenergy, and on the behavior of larger process particles. In theimpeller region the highest kinetic energies are about 15%higher upstream of the baffle than at the middle plane betweenthe baffles. The highest energy level in the middle plane isactually the lowest value and is therefore not representativewhen rotation symmetry is assumed.

Local energy dissipation rates have been investigated, andthe integration of the local energy dissipation rates overdifferent control volumes has been compared with macroscopicenergy balance calculations. The discrepancy is significant.Different reasons have been analyzed and recommendations forfurther investigation are given. I

n the outflow region there is a significant variation alsoin the direction of the instantaneous velocity, which may leadto direction bias in the case of non-spherical measurementvolume. In order to account for this direction bias, amathematical model is developed to estimate the projected areaof the measurement volume in LDA or PDA. It is shown that theprojected area variation can lead to a significant directionbias in determination of time averaged values and localparticle concentration in a highly turbulent stirred tank flow.This bias is however negligible for an orthogonal optical setup, as is used in the present study.

Keywords:Hydrodynamics, phase-Doppler anemometer,suspension, pitched-blade turbine, anisotropy, turbulence,Reynolds stresses, trailing vortex, kinetic energy, stirredtank

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Solis, Suraye Rori. "Estimating Flow Through Rock Weirs." Thesis, Virginia Tech, 2019. http://hdl.handle.net/10919/90401.

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Rock weirs are small dam-like structures composed of large loose rock commonly found in ecological engineering design. By appearing more natural than concrete structures, rock weirs are preferred for use as hydraulic control structures in river engineering, stormwater management, and constructed wetlands. Rock weirs increase hydraulic head upstream, and facilitate fish passage, channel stabilization, floodplain reconnection, and in-stream habitat creation. When used in constructed wetlands, rock weirs play a valuable role in developing appropriate wetland hydrology. Although rock weirs are commonly used, a deficit of knowledge exists relating to the stage-discharge relationship of these structures. Therefore, the goal of this research was to determine a weir equation and corresponding discharge coefficients that improve predictions of flow through rock weirs. A flume study was conducted to develop a rock weir equation and discharge coefficients. Scaled model rock weirs were tested in a 1 m x 8 m x 0.4 m recirculating flume. Rock weirs varied by length (0.152 m, 0.305 m, and 0.457 m), depth (0.152 m and 0.305 m), and minimum rock diameter (12.7 mm, 19.1 mm, 25.4 mm). Three channel slopes were used (0%, 0.5%, 1%), and the flume discharge was varied for five water stages for each rock weir. Buckingham Pi analysis was used to develop seven dimensionless parameters. Regression analyses were then used to develop a model for discharge and the discharge coefficient. Results showed that weir length and depth play a significant role in predicting the discharge coefficient of rock weirs.
Master of Science
Rock weirs are small dam-like structures composed of large loose rock; by appearing more natural, they are preferred for use in river engineering, stormwater management, and constructed wetlands. Rock weirs increase upstream water depth, improving fish passage, channel stabilization, floodplain reconnection, and in-stream habitat creation. When used in design of constructed wetlands, rock weirs are used to establish the necessary water depths for a given type of wetland. Although rock weirs are commonly used in engineering design, there are no equations to predict water velocity or flow rate across these structures. Therefore, the goal of this research was to determine a weir equation that improves predictions of flow through rock weirs. A flume study was conducted to develop a rock weir equation. Miniature rock weirs were tested in a 1 m x 8 m x 0.4 m recirculating laboratory channel. Rock weirs varied by length (0.152 m, 0.305 m, and 0.457 m), depth (0.152 m and 0.305 m), and minimum rock diameter (12.7 mm, 19.1 mm, 25.4 mm). Three channel slopes were used (0%, 0.5%, 1%), and the water flow rate was varied for five water depths for each rock weir. Statistical analyses were conducted to determine an equation that predicts water flow through rock weirs for use in engineering design. Results showed that weir length and depth played a significant role in predicting water flow through rock weirs.
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Stevenson, Philip Mark. "A study of factors affecting the coefficient of discharge of twinned poppet-valves." Thesis, Queen's University Belfast, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.314165.

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Kim, Namgyun. "Numerical Study on Debris Flow Behavior with Two Sabo Dams." 京都大学 (Kyoto University), 2015. http://hdl.handle.net/2433/200499.

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Carlsson, Per. "Flow Through a Throttle Body : A Comparative Study of Heat Transfer, Wall Surface Roughness and Discharge Coefficient." Thesis, Linköping University, Department of Management and Engineering, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-8378.

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When designing a new fuel management system for a spark ignition engine the amount of air that is fed to the cylinders is highly important. A tool that is being used to improve the performance and reduce emission levels is engine modeling were a fuel management system can be tested and designed in a computer environment thus saving valuable setup time in an engine test cell. One important part of the modeling is the throttle which regulates the air. The current isentropic model has been investigated in this report. A throttle body and intake manifold has been simulated using Computational Fluid Dynamics (CFD) and the influence of surface heating and surface wall roughness has been calculated. A method to calculate the effective flow area has been constructed and tested by simulating at two different throttle plate angles and several pressure ratios across the throttle plate. The results show that both surface wall roughness and wall heating will reduce the mass flow rate compared to a smooth and adiabatic wall respectively. The reduction is both dependent on pressure ratio and throttle plate angle. The effective area has showed to follow the same behaviour as the mass flow rate for the larger simulated throttle plate angle 31 degrees, i.e. an increase as the pressure drop over the throttle plate becomes larger. At the smaller throttle plate angle 21 degrees, the behaviour is completely different and a reduction of the effective area can be seen for the highest pressure drop where a increase is expected.


När ett nytt bränslesystem ska designas till en bensinmotor är det viktigt att veta hur stor mängd luft som hamnar i cylindrarna. Ett verktyg som är på frammarsch för att förbättra prestanda och minska emissioner är modellbaserad simulering. Med hjälp av detta kan ett bränslesystem designas och testas i datormiljö och därigenom spara dyrbar tid som annars måste tillbringas i en motortestcell. En viktig del av denna modellering är spjället eller trotteln vilken reglerar luften. I denna rapport har studier gjort på den nuvarande isentropiska modellen. Ett spjällhus och insugsgrenrör har simulerats med hjälp av Computational Fluid Dynamics (CFD) och påverkan av värme samt ytjämnhet på väggen har beräknats. En metod att beräkna den effektiva genomströmmade arean har konstruerats och testats vid två olika spjällvinklar samt flertalet tryckkvoter över spjället. Resultaten visar att både en uppvärmd vägg och en vägg med skrovlighet kommer att minska massflödet jämfört med en adiabatisk respektive en slät vägg. Minskningen har både spjällvinkel samt tryckkvots beroende. Den effektiva genomströmmade arean har visats sig följa samma beteende som massflödet vid den större simulerade spjällvinkeln 31 grader, det vill säga öka med ökat tryckfall över spjället. Vid den mindre vinkeln 21 grader, är beteendet helt annorlunda jämfört med massflödet och en minskning av den effektiva arean kan ses vid det största tryckfallet där en ökning förväntades.

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Hollingshead, Colter L. "Discharge Coefficient Performance of Venturi, Standard Concentric Orifice Plate, V-Cone, and Wedge Flow Meters at Small Reynolds Numbers." DigitalCommons@USU, 2011. https://digitalcommons.usu.edu/etd/869.

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The relationship between the Reynolds number (Re) and discharge coefficients (C) was investigated through differential pressure flow meters. The focus of the study was directed toward very small Reynolds numbers commonly associated with pipeline transportation of viscous fluids. There is currently a relatively small amount of research that has been performed in this area for the Venturi, standard orifice plate, V-cone, and wedge flow meters. The Computational Fluid Dynamics (CFD) program FLUENT© was used to perform the research, while GAMBIT© was used as the preprocessing tool for the flow meter models created. Heavy oil and water were used separately as the two flowing fluids to obtain a wide range of Reynolds numbers with high precision. Multiple models were used with varying characteristics, such as pipe size and meter geometry, to obtain a better understanding of the C vs. Re relationship. All of the simulated numerical models were compared to physical data to determine the accuracy of the models. The study indicates that the various discharge coefficients decrease rapidly as the Reynolds number approaches 1 for each of the flow meters; however, the Reynolds number range in which the discharge coefficients were constant varied with meter design. The standard orifice plate does not follow the general trend in the discharge coefficient curve that the other flow meters do; instead as the Re decreases, the C value increases to a maximum before sharply dropping off. Several graphs demonstrating the varying relationships and outcomes are presented. The primary focus of this research was to obtain further understanding of discharge coefficient performance versus Reynolds number for differential producing flow meters at very small Reynolds numbers.
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8

Yildirim, Tugce. "Scrutinization Of Flow Characteristics Through Orifices." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12612451/index.pdf.

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Orifices are essential devices for measurement and control of flow. It is important to define the flow field and understand the flow characteristics behind an orifice for the sake of reliability measures in many hydraulic engineering applications. Since analytical and experimental solutions are restricted, a numerical solution is obtained using volume of fluid (VOF) method with the CFD solver, FLUENT, for sharp crested orifices, orifice tubes and slots. The results are compared to the available data in the literature
also a large spectrum of data collection has been achieved.
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9

Mandal, Anirban. "Computational Modeling of Non-Newtonian Fluid Flow in Simplex Atomizer." University of Cincinnati / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1202997834.

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Sasson, Jonathan. "Small Scale Mass Flow Plug Calibration." Case Western Reserve University School of Graduate Studies / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=case1417540797.

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Books on the topic "Impeller discharge flow coefficient"

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Carlson, John R. Two-dimensional converging-diverging rippled nozzles at transonic speeds. Hampton, Va: Langley Research Center, 1994.

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Carlson, John R. Two-dimensional converging-diverging rippled nozzles at transonic speeds. Hampton: National Aeronautics and Space Administration, Langley Research Center, 1994.

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Carlson, John R. Two-dimensional converging-diverging rippled nozzles at transonic speeds. Hampton, Va: Langley Research Center, 1994.

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Experimental and analytical studies of flow through a ventral and axial exhaust nozzle system for STOVL aircraft. [Washington, DC]: National Aeronautics and Space Administration, 1991.

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R, DeBonis James, and United States. National Aeronautics and Space Administration., eds. Experimental and analytical studies of flow through a ventral and axial exhaust nozzle system for STOVL aircraft. [Washington, DC]: National Aeronautics and Space Administration, 1991.

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United States. National Aeronautics and Space Administration., ed. RSRM 10% Scale Model drilled hole plate tests: Final report, contract NAS8-40347. Huntsville, AL: The Operation, 1996.

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C, Asbury Scott, and Langley Research Center, eds. Two-dimensional converging-diverging rippled nozzles at transonic speeds. Hampton, Va: National Aeronautics and Space Administration, Langley Research Center, 1994.

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C, Asbury Scott, and Langley Research Center, eds. Two-dimensional converging-diverging rippled nozzles at transonic speeds. Hampton, Va: National Aeronautics and Space Administration, Langley Research Center, 1994.

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C, Asbury Scott, and Langley Research Center, eds. Two-dimensional converging-diverging rippled nozzles at transonic speeds. Hampton, Va: National Aeronautics and Space Administration, Langley Research Center, 1994.

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Book chapters on the topic "Impeller discharge flow coefficient"

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Hazby, H. R., M. V. Casey, R. Numakura, and H. Tamaki. "Design and testing of a high flow coefficient mixed flow impeller." In 11th International Conference on Turbochargers and Turbocharging, 55–64. Elsevier, 2014. http://dx.doi.org/10.1533/978081000342.55.

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"Chapter 1 Discharge and Pressure Loss Coefficient Analysis of Non-Newtonian Fluid Flow Through Orifice Meter Using CFD." In Process Modeling, Simulation, and Environmental Applications in Chemical Engineering, edited by A. Tamrakar and S. A. Yadav, 1–18. Apple Academic Press, 2016. http://dx.doi.org/10.1201/9781315366449-2.

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Benham, Robert, and Fayyaz Rehman. "An Investigation into the Exploratory Use of Additive Manufacturing in Weir Design and Open Channel Flow." In Advances in Transdisciplinary Engineering. IOS Press, 2021. http://dx.doi.org/10.3233/atde210017.

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Additive Manufacturing (AM) offers a range of possibilities in fluid flow research. An existing 2.5 m open channel fluid flow experiment contains a set of standard weirs which are limited in design. This research will compare experimental AM weirs (e.g. labyrinth, piano, catenary), that would not be possible on some laser-cut polymer or machined aluminium weirs. Due to the bespoke complex nature of weirs’ design other manufacturing methods would be too expensive and impossible to use. AM technology allows a cost-effective solution for progressive design modifications to be implemented throughout investigations. This paper will highlight comparisons made between a range of AM produced weirs in terms of flow rate, fluid velocity profile, water level height and discharge coefficient. Computation fluid dynamic modelling (CFD) will also be used to verify, analyse, and compare results. Based on the experimental results and verification, the paper will also discuss the suitability of application of AM techniques in fluid flow analysis.
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Esther Babalola, Toju, Philip Gbenro Oguntunde, Ayodele Ebenezer Ajayi, and Francis Omowonuola Akinluyi. "Future Climate Change Impacts on River Discharge Seasonality for Selected West African River Basins." In Weather Forecasting [Working Title]. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.99426.

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The changing climate is a concern to sustainable water resources. This study examined climate change impacts on river discharge seasonality in two West African river basins; the Niger river basin and the Hadejia-Jama’are Komadugu-Yobe Basin (HJKYB). The basins have their gauges located within Nigeria and cover the major climatic settings. Here, we set up and validated the hyper resolution global hydrological model PCR-GLOBWB for these rivers. Time series plots as well five performance evaluation metrics such as Kling–Gupta efficiency (KGE),); the ratio of RMSE-observations standard deviation (RSR); per cent bias (PBIAS); the Nash–Sutcliffe Efficiency criteria (NSE); and, the coefficient of determination (r2), were employed to verify the PCR-GLOBWB simulation capability. The validation results showed from satisfactory to very good on individual rivers as specified by PBIAS (−25 to 0.8), NSE (from 0.6 to 0.8), RSR (from 0.62 to 0.4), r2 (from 0.62 to 0.88), and KGE (from 0.69 to 0.88) respectively. The impact assessment was performed by driving the model with climate projections from five global climate models for the representative concentration pathways (RCPs) 4.5 and 8.5. We examined the median and range of expected changes in seasonal discharge in the far future (2070–2099). Our results show that the impacts of climate change cause a reduction in discharge volume at the beginning of the high flow period and an increase in discharge towards the ending of the high flow period relative to the historical period across the selected rivers. In the Niger river basin, at the Lokoja gauge, projected decreases added up to 512 m3/s under RCP 4.5 (June to July) and 3652 m3/s under RCP 8.5 (June to August). The three chosen gauges at the HJKYB also showed similar impacts. At the Gashua gauge, discharge volume increased by 371 m3/s (RCP8.5) and 191 m3/s (RCP4.5) from August to November. At the Bunga gauge, a reduction/increase of -91 m3/s/+84 m3/s (RCP 8.5) and -40 m3/s/+31 m3/s/(RCP 4.5) from June to July/August to October was simulated. While at the Wudil gauge, a reduction/increase in discharge volumes of −39/+133 m3/s (RCP8.5) and −40/133 m3/s (RCP 4.5) from June to August/September to December is projected. This decrease is explained by a delayed start of the rainy season. In all four rivers, projected river discharge seasonality is amplified under the high-end emission scenario (RCP8.5). This finding supports the potential advantages of reduced greenhouse gas emissions for the seasonal river discharge regime. Our study is anticipated to provide useful information to policymakers and river basin development authorities, leading to improved water management schemes within the context of changing climate and increasing need for agricultural expansion.
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"Performance of Adsorptive Heat Storage Devices for Heat Supply." In Technology Development for Adsorptive Heat Energy Converters, 124–73. IGI Global, 2021. http://dx.doi.org/10.4018/978-1-7998-4432-7.ch005.

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The chapter is focused on modelling of performance of adsorptive heat storage devices and estimation of performance of heat storage devices. Two groups of models of adsorptive heat storage units suggested previous researchers are analyzed. The first one is focused on predicting the heat energy storage density, it being based on Dubinin-Polanyi theory. The second one is devoted to analyzing the kinetic of adsorption processes and performance of the adsorber or adsorptive-desorptive reactor filled with traditional adsorbent or salt which forms crystalline hydrates. The key drawback of both groups of models concerns with considering only one stage of exploitation of adsorptive heat storage device in spite of its operating in two-stage mode, that is, alternating discharge (adsorption) and charge (regeneration). It inhibits estimation of efficiency of adsorptive heat storage device basing on full operating cycle and its involving in heat supply system. Two algorithms for estimation of operating parameters are proposed by authors for closed-type and open-type heat storage devices. The algorithm for calculation of operating parameters of closed type adsorptive heat storage device is proposed: calculation of the mass transfer coefficient, adsorption, useful heat, that is, heat of adsorption, determination of the heat input, it being calculated as heat inputs for heating the adsorbent, device housing, water in the tank, evaporation of water in the tank, heating of the adsorbed water and desorption. Then efficiency factor is calculated. The operating characteristics of a closed-type heat energy storage device were studied when the composite adsorbent ‘silica gel – sodium sulphate' used. The effect of the humid airflow velocity on the efficiency factor is taken into account by introducing a coefficient equal to the value of the adsorption. An increase in the efficiency coefficient was stated when the velocity and relative humidity of the airflow. It is shown that the humid air flow temperature practically does not affect its value. Having been used the suggested algorithm, the optimal operating characteristics of an adsorptive heat storage device of a closed type based on a composite adsorbent ‘silica gel – sodium sulphate' for a private house heating system are revealed to be humid air velocities of 0.6 – 0.8 m/s and relative humidity 40 – 60%. When these operational data applied, the efficiency coefficient is shown to reach the maximum values (about 55%). Algorithm of calculation of operating parameter of open-type heat storage device includes computation of mass transfer coefficient, adsorption, useful heat (heat of adsorption), heat input for heating the adsorbent, device casing, water in the humidifier, evaporation of water, heating the adsorbed water, desorption, and calculating efficiency coefficient. Performance of open-type heat storage device based on the composite adsorbent ‘silica gel – sodium sulphate' is estimated. The optimal operating conditions of the heat accumulating device which allow operating with maximal magnitudes of efficiency coefficients 53 – 57% are stated to be humid airflow speed of 0.6 – 0.8 m/s and relative humidity of 40 – 60%. Correlation between efficiency factors obtained by experiments and calculated with suggested algorithm is confirmed. The possibility of reducing the power consumption when heat storage devices applied in 2,4 – 90 times versus decentralized heating systems on basis of solid fuel boiler, gas boiler and electric boiler is stated when open-type sorptive heat storage device used. Results of the study can be used to develop adsorptive storage devices in decentralized heat supply and ventilation systems and adsorption units for utilization of low-temperature waste heat.
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"Main Characteristics of an Aquifer The main function of the aquifer is to provide underground storage for the retention and release of gravitational water. Aquifers can be characterized by indices that reflect their ability to recover moisture held in pores in the earth (only the large pores give up their water easily). These indices are related to the volume of exploitable water. Other aquifer characteristics include: • Effective porosity corresponds to the ratio of the volume of “gravitational” water at saturation, which is released under the effect of gravity, to the total volume of the medium containing this water. It generally varies between 0.1% and 30%. Effective porosity is a parameter determined in the laboratory or in the field. • Storage coefficient is the ratio of the water volume released or stored, per unit of area of the aquifer, to the corresponding variations in hydraulic head 'h. The storage coefficient is used to characterize the volume of useable water more precisely, and governs the storage of gravitational water in the reservoir voids. This coefficient is extremely low for confined groundwater; in fact, it represents the degree of the water compression. • Hydraulic conductivity at saturation relates to Darcy’s law and characterizes the effect of resistance to flow due to friction forces. These forces are a function of the characteristics of the soil matrix, and of the fluid viscosity. It is determined in the laboratory or directly in the field by a pumping test. • Transmissivity is the discharge of water that flows from an aquifer per unit width under the effect of a unit of hydraulic gradient. It is equal to the product of the saturation hydraulic conductivity and of the thickness (height) of the groundwater. • Diffusivity characterizes the speed of the aquifer response to a disturbance: (variations in the water level of a river or the groundwater, pumping). It is expressed by the ratio between the transmissivity and the storage coefficient. Effective and Fictitious Flow Velocity: Groundwater Discharge As we saw earlier in this chapter, water flow through permeable layers in saturated zones is governed by Darcy’s Law. The flow velocity is in reality the fictitious velocity of the water flowing through the total flow section. Bearing in mind that a section is not necessarily representative of the entire soil mass, Figure 7.7 illustrates how flow does not follow a straight path through a section; in fact, the water flows much more rapidly through the available pathways (the tortuosity effect). The groundwater discharge Q is the volume of water per unit of time that flows through a cross-section of aquifer under the effect of a given hydraulic gradient. The discharge of a groundwater aquifer through a specified soil section can be expressed by the equation:." In Hydrology, 229–30. CRC Press, 2010. http://dx.doi.org/10.1201/b10426-57.

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Conference papers on the topic "Impeller discharge flow coefficient"

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Qiu, Xuwen, David Japikse, Jinhui Zhao, and Mark R. Anderson. "Analysis and Validation of a Unified Slip Factor Model for Impellers at Design and Off-Design Conditions." In ASME Turbo Expo 2010: Power for Land, Sea, and Air. ASMEDC, 2010. http://dx.doi.org/10.1115/gt2010-22164.

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This paper presents a unified slip model for axial, radial, and mixed-flow impellers. The core assumption of the model is that the flow deviation or slip velocity at impeller exit is mainly originated from the blade loading near the discharge of an impeller and its subsequent relative eddy in the impeller passage. The blade loading is estimated and then used to derive the slip velocity using Stodola’s assumption. The final form of the slip factor model can be successfully related to Carter’s rule [1] for axial impellers and Stodola’s [2] slip model for radial impellers, making the case for this model to be applicable to axial, radial, and mixed-flow impellers. Unlike conventional slip factor models for radial impellers, the new slip model suggests that the flow coefficient at the impeller exit is an important variable for the slip factor when there is significant blade turning at the impeller discharge. This explains the interesting off-design trends for slip factor observed from experiments, such as the rise of the slip factor with flow coefficient in the Eckardt A impeller [3]. Extensive validation results for this new model are presented in this paper. Several cases are studied in detail to demonstrate how this new model can capture the slip factor variation at the off-design conditions. Furthermore, a large number of test data from more than 90 different compressors, pumps, and blowers were collected. Most cases are radial impellers, but a few axial impellers are also included. The test data and model predictions of the slip factor are compared at both design and off-design flow conditions. In total, over 1,650 different flow conditions are evaluated. The unified model shows a clear advantage over the traditional slip factor correlations, such as the Busemann-Wiesner model [4], when off-design conditions are considered.
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Huang, Shengqin, Zhenxia Liu, Yaguo Lu, Yan Yan, and Xiaochun Lian. "Validations of Some Slip Factor Models for Mixed-Flow Impellers." In ASME 2008 Fluids Engineering Division Summer Meeting collocated with the Heat Transfer, Energy Sustainability, and 3rd Energy Nanotechnology Conferences. ASMEDC, 2008. http://dx.doi.org/10.1115/fedsm2008-55202.

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Accurate modeling of the slip factor is essential for correct prediction of the mixed-flow impeller performance, but the slip factor model well-known for mixed-flow impeller is relatively rare. Two ways for calculating mixed-flow impeller slip factor are present in this paper: (1) Using impeller exit inclination angle correction to transform the slip factor for centrifugal impeller to mixed-flow machine. (2) Setting up model that can be used to mixed-flow machine directly. Based on these two ways, there are six slip factor models chosen for mixed-flow impeller, including models of Wiesner, Stodola, Staniz, Paeng, Backstrom and Qiu. And they are need to be validated by experiments data to find a proper method for mixed-flow machine. The test data are reproduced from Wiesner’s work and nine mixed-flow impellers are included. Experiment and simulation (including six slip factors) have been conducted and the results show that: (1) slip factor models of centrifugal impeller can be used to mixed-flow impeller while no proper mixed-flow slip factor models exist. If the impeller discharge inclination angle is greater than 45 degree, then these models can be used for mixed-flow impellers directly without transformation. (2) Equivalent blade number exists in mixed-flow impeller and it may have critical value. There are only little differences between results calculated by various slip factor models in the condition of equivalent blade number beyond the critical value. Otherwise it has to choose proper slip factor models as different situations while the equivalent blade number is less than the critical value. (3) Blade number, impeller exit inclination angle and exit blade angle of mixed-flow impeller are dominated over slip factor, but blade turning rate and flow coefficient have to be taken into account for more exact solution.
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Qiu, Xuwen, Chanaka Mallikarachchi, and Mark Anderson. "A New Slip Factor Model for Axial and Radial Impellers." In ASME Turbo Expo 2007: Power for Land, Sea, and Air. ASMEDC, 2007. http://dx.doi.org/10.1115/gt2007-27064.

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This paper proposes a unified slip model for axial, radial, and mixed flow impellers. For many years, engineers designing axial and radial turbomachines have applied completely different deviation or slip factor models. For axial applications, the most commonly used deviation model has been Carter’s rule or its derivatives. For centrifugal impellers, Wiesner’s correlation has been the most popular choice. Is there a common thread linking these seemingly unrelated models? This question becomes particularly important when designing a mixed flow impeller where one has to choose between axial or radial slip models. The proposed model in this paper is based on blade loading, i.e., the velocity difference between the pressure and suction surfaces, near the discharge of the impeller. The loading function includes the effect of blade rotation, blade turning, and the passage area variation. This velocity difference is then used to calculate the slip velocity using Stodola’s assumption. The final slip model can then be related to Carter’s rule for axial impellers and Stodola’s slip model for radial impellers. This new slip model suggests that the flow coefficient at the impeller exit is an important variable for the slip factor when there is blade turning at the impeller discharge. This may explain the interesting slip factor trend observed from experiments, such as the rise of the slip factor with flow coefficient in Eckardt A impeller. Some validation results of this new model are presented for a variety of applications, such as radial compressors, axial compressors, pumps, and blowers.
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Arndt, N., A. J. Acosta, C. E. Brennen, and T. K. Caughey. "Experimental Investigation of Rotor-Stator Interaction in a Centrifugal Pump With Several Vaned Diffusers." In ASME 1989 International Gas Turbine and Aeroengine Congress and Exposition. American Society of Mechanical Engineers, 1989. http://dx.doi.org/10.1115/89-gt-62.

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This paper describes an experimental investigation of rotor–stator interaction in a centrifugal pump with several vaned diffusers. Steady and unsteady diffuser vane pressure measurements were made for a two–dimensional test impeller. Unsteady impeller blade pressure measurements were made for a second two–dimensional impeller with blade number and blade geometry identical to the two–dimensional impeller used for the diffuser vane pressure measurements. The experiments were conducted for different flow coefficients and different radial gaps between the impeller blade trailing edge and the diffuser vane leading edge (5% and 8% of the impeller discharge radius). The largest pressure fluctuations on the diffuser vanes and the impeller blades were found to be of the same order of magnitude as the total pressure rise across the pump. The largest pressure fluctuations on the diffuser vanes were observed to occur on the suction side of the vane near the vane leading edge, whereas on the impeller blades the largest fluctuations were observed to occur at the blade trailing edge. However, the dependence of the fluctuations on the flow coefficient was found to be different for the diffuser vanes and the impeller blades; on the vane suction side, the fluctuations were largest for the maximum flow coefficient and decreased with decreasing flow coefficient, whereas at the blade trailing edge, the fluctuations were smallest for the maximum flow coefficient and increased with decreasing flow coefficient. Increasing the number of the diffuser vanes resulted in a significant decrease of the impeller blade pressure fluctuations. The resulting lift on the diffuser vanes was computed from the vane pressure measurements; the magnitude of the fluctuating lift was found to be larger than the steady lift.
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Braun, O., J. L. Kueny, and F. Avellan. "Numerical Analysis of Flow Phenomena Related to the Unstable Energy-Discharge Characteristic of a Pump-Turbine in Pump Mode." In ASME 2005 Fluids Engineering Division Summer Meeting. ASMEDC, 2005. http://dx.doi.org/10.1115/fedsm2005-77015.

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Regions of positive slope in the pressure-discharge characteristics are one of the major concerns in design and operation of centrifugal pumps, as they are limiting the admissible operating range to values above the critical discharge. The industrial pump turbine of specific speed ν = 0.42 (nq = 66 min−1) proposed as QNET-CFD test case TA6-04 shows a marked saddle in the energy-discharge characteristic associated to a sudden drop of efficiency versus discharge at part load. The pump-turbine consists of a shrouded impeller with five blades, a diffuser with 22 guide and stay vanes and a spiral casing. CFD flow simulations on a reduced model were carried out with a finite volume Navier-Stokes code (CFX-5.7) using block-structured hexahedral meshes and the Menter-SST Turbulence model. Control of numerical quality has been performed. Reduced models with relatively low computational effort (mixing plane interface) already permit to capture the drop in efficiency and energy coefficient to analyze the flow phenomena inducing the drop of the energy coefficient Ψ that occurs at partial discharge. Analysis of local flow patterns and energy and velocity distributions at the rotor-stator interface that are related to the onset of recirculation are presented.
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Boccazzi, A., R. Sala, and P. Gaetani. "Flow Field in the Vaned Diffuser of a Centrifugal Pump at Different Vane Setting Angles." In ASME-JSME-KSME 2011 Joint Fluids Engineering Conference. ASMEDC, 2011. http://dx.doi.org/10.1115/ajk2011-06068.

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Particle image velocimetry (2D-PIV) has been used for the investigation of the time averaged flow field inside the vaned diffuser of a centrifugal pump operating at best efficiency point. Pump performances and the diffuser flow field were analysed for three different vane setting angles. It was evidenced that flow coefficient at the best efficiency point decreases with the diffuser setting angle reduction. From 2D-PIV measurements in five different blade to blade planes, span-wise averaged flow angles and velocity distribution were computed. It was evidenced an influence of the diffuser setting angle on the span-wise distribution of the flow rate and of the absolute mass averaged flow angle at impeller discharge. An overturning, at the diffuser discharge was also evidenced for the two highest setting angles. 2D-PIV flow fields are presented in three different pseudo-secondary planes in order to enlighten the cross flows affecting the diffuser flow field.
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Tian, Shuqing, Qin Zhang, and Hui Liu. "CFD Investigation of Vane Nozzle and Impeller Design for HPT Blade Cooling Air Delivery System." In ASME Turbo Expo 2013: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/gt2013-95396.

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In the design of a HPT blade cooling air delivery system, sufficient supply pressure and lower relative total temperature are required to guarantee HPT blades working properly in the high temperature environment. The pre-swirl vane nozzles and the radial impellers are used in the delivery system with lower radial location of pre-swirl nozzle to achieve the requirements. In this paper, CFD analysis is utilized for designing the vane nozzles and the radial impellers. Two HPT blade cooling air delivery systems were explored. The baseline is a system without impellers, and the alternative is a system with impellers. The results show that the impeller contributes to the delivery system by pumping effectiveness thus decreasing the extracted air pressure. The parity of swirl ratio between the flow and the broach slots is a main factor that decreases the system pressure loss, which can be improved by the radial impellers. The well-designed contoured radial-impeller vane with 30° front angle and 20° trailing angle is recommended in the blade cooling air delivery system design because of its good aerodynamic performance and closely radial outflow. The cascade vane nozzle with more than 70° angle turn is recommended in the pre-swirl nozzle design. It has a good aerodynamic performance with discharge coefficient greater than 0.99 and deviation angle less than 1.3°. The well-designed radial impeller pays big contributions to the blade cooling air delivery system with 11.4% increase of the thermal effectiveness and 10.2% decrease of the pressure loss versus the system without impellers.
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Tanaka, Teiichi. "Thermodynamic Effect and Cavitation Performance of a Cavitating Centrifugal Pump." In ASME-JSME-KSME 2011 Joint Fluids Engineering Conference. ASMEDC, 2011. http://dx.doi.org/10.1115/ajk2011-06025.

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The thermodynamic effect which affects the cavitation performance of a cavitating centrifugal pump was investigated experimentally using liquid nitrogen. To measure the pump cavitation performance, a test setup which could carry out experiments using both liquid nitrogen and cold water was constructed. The test setup consisted of a suction tank, a test pump, a mass flow meter, a ball valve and pipes. Vacuum-insulated pipes were used. The test pump was a centrifugal type magnetic pump, and two impellers, which differed in cavitation performance, were used in experiments. Cavitation performance using liquid nitrogen or cold water could be obtained from the measurement of the pump suction and delivery pressure, the pump suction and delivery temperature, and the discharge flow rate. And an improvement in pump cavitation performance could be seen when comparing the experimental results from using liquid nitrogen with those from using cold water. The experimental results indicated that cavitation performance using liquid nitrogen was better than that using cold water. This improvement in cavitation performance was thought to be due to the thermodynamic effect of cavitation. And the estimated temperature depression due to the thermodynamic effect decreased with a decreasing flow coefficient. Moreover, it was shown that the estimated temperature depression due to the thermodynamic effect on the low cavitation performance impeller was larger than that on the high cavitation performance impeller at the same flow coefficient.
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Strongin, Mikhail P. "CFD Modeling of Mixing Process in Pump for Two Liquids With Different Temperatures." In ASME 2010 3rd Joint US-European Fluids Engineering Summer Meeting collocated with 8th International Conference on Nanochannels, Microchannels, and Minichannels. ASMEDC, 2010. http://dx.doi.org/10.1115/fedsm-icnmm2010-30969.

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The mixing of two or more liquids is very common in many industrial applications. In some cases the liquids are set on the pump inlet. The mixing process of two non-isothermal fluids in a pump is investigated in the presented work. Different pump geometries have been studied with comparison steady state and averaged transient results. Presented work considers the influence of the difference in temperatures of two mixing liquids on the mixing process. The pump model consists of suction, impeller and discharge parts which were meshed and calculated together. This, for instance, naturally permits the effects of non-uniformity of velocity and liquids concentrations distribution on the impeller eye and on the inlet of the discharge segment to be taken into account. Dependence of the density of liquids on the temperature is taken into account. Results of previous work with isothermal liquids demonstrated significant change in the mixing uniformity coefficient γ depending on where on the inlet the injected fluid is located and effect of very fast fading oscillations of concentration with blade passing frequency. For injection with angular symmetry on the pump inlet, γ is close to 1 (ideal mixture) on the outlet compared with γ less than 0.9 for strong angular asymmetry injection on the pump inlet, which is not sufficient for some applications. Results of presented work show the small, but visible, difference in the mixing uniformity coefficient for isothermal and non-isothermal liquids with the same flow rates on the inlet. Temperature uniformity coefficient is very close to the mixing uniformity coefficient, which is obvious, because of closeness of turbulent diffusivity and thermal conductivity coefficients.
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Nagahara, Takahide, and Yasuhiro Inoue. "Investigation of Hydraulic Design for High Performance Multi-Stage Pump Using CFD." In ASME 2009 Fluids Engineering Division Summer Meeting. ASMEDC, 2009. http://dx.doi.org/10.1115/fedsm2009-78418.

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We investigated the hydraulic design and flow field in a multi-stage pump to achieve high efficiency and low cavitation performance using computational fluid dynamics (CFD) and experimental approaches. The subject of the investigation is a four-stage centrifugal pump, which consists of a suction bend, impellers, stators, and a discharge volute. In designing a high performance multi-stage pump, it is important to investigate the interaction of flows between the stator and impeller, which were also investigated individually for minimizing hydraulic loss. The flow field in the suction bend, therefore, was simulated first using conventional CFD based on the Reynolds-Averaged Navier-Stokes (RANS) equations, and the calculated result of the flow field at the outlet of the suction bend was used to design the impeller inlet shape at the design-flow rate. To obtain a high-performance impeller shape, the effect of the meridional configuration of the impeller on hydraulic loss was examined using a parameter design based on conventional CFD results. The meridional shape was composed of several design parameters such as inlet, outlet diameter and so on, and a few parameters, which contribute to reducing hydraulic loss significantly, were extracted using the parameter design. Therefore, we obtained a highly efficient impeller shape by adjusting those important parameters. Finally, to evaluate and confirm the interaction of the flows between the stators and impeller, a numerical calculation of the four-stage pump was carried out using advanced large eddy simulation (LES). As a result, we obtained the predicted flow field in the four-stage pump. There was no significant flow separation at the inlet of each impeller and it was confirmed that the blade design was appropriate. The hydraulic performance of the four-stage pump was also confirmed using a model pump test. The inception of cavitation was observed and the cavitation coefficient estimated using experimental results was in good agreement with the CFD prediction. As a result of this development including the investigation described above, the hydraulic shape of a highly efficient and high-cavitation performing four-stage pump was obtained.
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Reports on the topic "Impeller discharge flow coefficient"

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Strakey, P. A., and D. G. Talley. The Effect of Manifold Cross-Flow on the Discharge Coefficient Sharp-Edged Orifices. Fort Belvoir, VA: Defense Technical Information Center, March 1998. http://dx.doi.org/10.21236/ada409685.

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