scholarly journals 3-D Viscous Flow Analysis of a Mixed Flow Pump Impeller

2001 ◽  
Vol 7 (1) ◽  
pp. 53-63 ◽  
Author(s):  
Steven M. Miner
Keyword(s):  
Static Pressure ◽  
Stokes Equations ◽  
Leading Edge ◽  
Flow Coefficient ◽  
Design Parameters ◽  
Design Environment ◽  
Suction Surface ◽  
Mixed Flow ◽  
Pump Impeller ◽  
Flow Pump

This paper presents the results of a study using a coarse grid to analyze the flow in the impeller of a mixed flow pump. A commercial computational fluid dynamics code (FLOTRAN) is used to solve the 3-D Reynolds Averaged Navier Stokes equations in a rotating cylindrical coordinate system. The standardk-εturbulence model is used. The mesh for this study uses 26,000 nodes and the model is run on a SPARCstation 20. This is in contrast to typical analyses using in excess of 100,000 nodes that are run on a super computer platform. The smaller mesh size has advantages in the design environment. Stage design parameters are, rotational speed 1185 rpm, flow coefficientφ=0.116, head coefficientψ=0.094, and specific speed 2.01 (5475 US). Results for the model include circumferentially averaged results at the leading and trailing edges of the impeller, and analysis of the flow field within the impeller passage. Circumferentially averaged results include axial and tangential velocities, static pressure, and total pressure. Within the impeller passage the static pressure and velocity results are presented on surfaces from the leading edge to the trailing edge, the hub to the shroud, and the pressure surface to the suction surface. Results of this study are consistent with the expected flow characteristics of mixed flow impellers, indicating that small CFD models can be used to evaluate impeller performance in the design environment.

Evaluation of Blade Passage Analysis Using Coarse Grids

2000 ◽  
Vol 122 (2) ◽  
pp. 345-348 ◽  
Author(s):  
Steven M. Miner
Keyword(s):  
Rotational Speed ◽  
Stokes Equations ◽  
Axial Flow ◽  
Measured Data ◽  
Flow Coefficient ◽  
Design Parameters ◽  
Mixed Flow ◽  
Specific Speed ◽  
Coarse Grids ◽  
Flow Pump

This paper presents the results of a study using coarse grids to analyze the flow in the impellers of an axial flow pump and a mixed flow pump. A commercial CFD code (FLOTRAN) is used to solve the 3-D Reynolds Averaged Navier Stokes equations in a rotating cylindrical coordinate system. The standard k−ε turbulence model is used. The meshes for this study use 22,000 nodes and 40,000 nodes for the axial flow impeller, and 26,000 nodes for the mixed flow impeller. Both models are run on a SPARCstation 20. This is in contrast to typical analyses using in excess of 100,000 nodes. The smaller mesh size has advantages in the design environment. Stage design parameters for the axial flow impeller are, rotational speed 870 rpm, flow coefficient ϕ=0.13, head coefficient ψ=0.06, and specific speed 2.97 (8101 US). For the mixed flow impeller the parameters are, rotational speed 890 rpm, flow coefficient ϕ=0.116, head coefficient ψ=0.094, and specific speed 2.01 (5475 US). Evaluation of the models is based on a comparison of circumferentially averaged results to measured data for the same impeller. Comparisons to measured data include axial and tangential velocities, static pressure, and total pressure. A comparison between the coarse and fine meshes for the axial flow impeller is included. Results of this study show that the computational results closely match the shapes and magnitudes of the measured profiles, indicating that coarse CFD models can be used to accurately predict performance. [S0098-2202(00)02202-1]

scholarly journals 3-D Viscous Flow Analysis of an Axial Flow Pump Impeller

1997 ◽  
Vol 3 (3) ◽  
pp. 153-161 ◽  
Author(s):  
Steven M. Miner
Keyword(s):  
Stokes Equations ◽  
Flow Analysis ◽  
Axial Flow ◽  
Flow Coefficient ◽  
Navier Stokes ◽  
Design Parameters ◽  
Pump Impeller ◽  
Flow Angle ◽  
Axial Flow Pump ◽  
Flow Pump

A commercial CFD code is used to compute the flow field within the first stage impeller of a two stage axial flow pump. The code solves the 3-D Reynolds Averaged Navier Stokes equations in a rotating cylindrical coordinate system using a standardk−εturbulence model. Stage design parameters are, rotational speed 870 rpm, flow coefficientφ=0.12, head coefficientψ=0.06, and specific speed 2.86 (8070 US). Results from the study include relative and absolute velocities, flow angles, and static and total pressures. Comparison is made to measured data available for the same impeller at two planes, one upstream of the impeller and the other downstream. The comparisons are for circumferentially averaged results and include axial and tangential velocities, impeller exit flow angle, static pressure, and total pressure. Results of this study show that the computational results closely match the shapes and magnitudes of the measured profiles, indicating that CFD can be used to accurately predict performance.

scholarly journals CFD Analysis of the First-Stage Rotor and Stator in a Two-Stage Mixed Flow Pump

2005 ◽  
Vol 2005 (1) ◽  
pp. 23-29 ◽  
Author(s):  
Steven M. Miner
Keyword(s):  
Stokes Equations ◽  
Flow Coefficient ◽  
Navier Stokes ◽  
Design Parameters ◽  
Mixed Flow ◽  
Two Stage ◽  
Navier Stokes Equations ◽  
Pressure Profiles ◽  
Turbulence Effects ◽  
Flow Pump

A commercial computational fluid dynamics (CFD) code is used to compute the flow field within the first-stage rotor and stator of a two-stage mixed flow pump. The code solves the 3D Reynolds-averaged Navier-Stokes equations in rotating and stationary cylindrical coordinate systems for the rotor and stator, respectively. Turbulence effects are modeled using a standardk−εturbulence model. Stage design parameters are rotational speed890 rpm, flow coefficientφ=0.116, head coefficientψ=0.094, and specific speed2.01(5475 US). Results from the study include velocities, and static and total pressures for both the rotor and stator. Comparison is made to measured data for the rotor. The comparisons in the paper are for circumferentially averaged results and include axial and tangential velocities, static pressure, and total pressure profiles. Results of this study show that the computational results closely match the shapes and magnitudes of the measured profiles, indicating that CFD can be used to accurately predict performance.

Performance Prediction of a Novel Design for Turbine Vane Film Cooling With Low Aerodynamic Loss and High Effectiveness

2004 ◽  
Author(s):  
William D. York ◽  
James H. Leylek
Keyword(s):  
Film Cooling ◽  
Stokes Equations ◽  
Density Ratio ◽  
Leading Edge ◽  
Cost Effective ◽  
Design Environment ◽  
Suction Surface ◽  
Reference Case ◽  
Aerodynamic Loss ◽  
Turbine Vane

A new film-cooling scheme for the suction surface of a gas turbine vane in a transonic cascade is studied numerically. The concept of the present design is to inject a substantial amount of coolant at a very small angle, approaching a “wall-jet,” through a single row of relatively few, large holes near the vane leading edge. The near-match of the coolant stream and mainstream momentums, coupled with the low coolant trajectory, theoretically results in low aerodynamic losses due to mixing. A minimal effect of the film cooling on the vane loading is also important to realize, as well as good coolant coverage and high adiabatic effectiveness. A systematic computational methodology, developed in the Advanced Computational Research Laboratory (ACRL) and tested numerous times on film-cooling applications, is applied in the present work. For validation purposes, predictions from two previous turbine airfoil film-cooling studies, both employing this same numerical method, are presented and compared to experimental data. Simulations of the new film-cooling configuration are performed for two blowing ratios, M=0.90 and M=1.04, and the density ratio of the coolant to the mainstream flow is unity in both cases. A solid vane with no film cooling is also studied as a reference case in the evaluation of losses. The unstructured numerical mesh contains about 5.5 million finite-volumes, after solution-based adaption. Grid resolution is such that the full boundary layer and all passage shocks are resolved. The Renormalization Group (RNG) k-ε turbulence model is used to close the Reynolds-averaged Navier-Stokes equations. Predictions indicate that the new film-cooling scheme meets design intent and has negligible impact on the total pressure losses through the vane cascade. Additionally, excellent coolant coverage is observed all the way to the trailing edge, resulting in high far-field effectiveness. Keeping the design environment in mind, this work represents the power of validated computational methods to provide a rapid and reasonably cost-effective analysis of innovative turbine airfoil cooling.

scholarly journals Anti-Cavitation Design of the Symmetric Leading-Edge Shape of Mixed-Flow Pump Impeller Blades

Symmetry ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 46 ◽  
Author(s):  
Di Zhu ◽  
Ran Tao ◽  
Ruofu Xiao
Keyword(s):  
Fluid Dynamics ◽  
Genetic Algorithm ◽  
Design Method ◽  
Leading Edge ◽  
Mixed Flow ◽  
Pump Impeller ◽  
Cavitation Performance ◽  
Optimal Sample ◽  
Dynamics Method ◽  
Flow Pump

Mixed-flow pumps compromise large flow rate and high head in fluid transferring. Long-axis mixed-flow pumps with radial–axial “spacing” guide vanes are usually installed deeply under water and suffer strong cavitation due to strong environmental pressure drops. In this case, a strategy combining the Diffusion-Angle Integral Design method, the Genetic Algorithm, and the Computational Fluid Dynamics method was used for optimizing the mixed-flow pump impeller. The Diffusion-Angle Integral Design method was used to parameterize the leading-edge geometry. The Genetic Algorithm was used to search for the optimal sample. The Computational Fluid Dynamics method was used for predicting the cavitation performance and head–efficiency performance of all the samples. The optimization designs quickly converged and got an optimal sample. This had an increased value for the minimum pressure coefficient, especially under off-design conditions. The sudden pressure drop around the leading-edge was weakened. The cavitation performance within the 0.5–1.2 Qd flow rate range, especially within the 0.62–0.78 Qd and 1.08–1.20 Qd ranges, was improved. The head and hydraulic efficiency was numerically checked without obvious change. This provided a good reference for optimizing the cavitation or other performances of bladed pumps.

An Experimental Study of Cavitation in a Mixed Flow Pump Impeller

1960 ◽  
Vol 82 (4) ◽  
pp. 929-940 ◽  
Author(s):  
G. M. Wood ◽  
J. S. Murphy ◽  
J. Farquhar
Keyword(s):  
Experimental Study ◽  
Static Pressure ◽  
Hydraulic Performance ◽  
Mixed Flow ◽  
Pump Impeller ◽  
Flow Models ◽  
Cavitation Performance ◽  
Pressure Profiles ◽  
Closed Water ◽  
Flow Pump

A mixed flow impeller design was tested with six, five, and four vanes in a closed water loop to study the effects of cavitation on hydraulic performance and the results were compared with the work of other investigators. Two idealized flow models for incipient cavitation were derived to illustrate limits of cavitation design. It was found that both vane blockage and solidity effects are important when designing for optimum cavitation performance. Data showing incidence and speed effects plus the tip static pressure profiles in cavitating and noncavitating flow are also presented.

Visual Cavitation Studies of Mixed Flow Pump Impellers

1963 ◽  
Vol 85 (1) ◽  
pp. 17-28 ◽  
Author(s):  
G. M. Wood
Keyword(s):  
High Speed ◽  
Leading Edge ◽  
Design Parameters ◽  
Performance Parameters ◽  
Mixed Flow ◽  
Wide Range ◽  
Closed Water ◽  
Flow Pump ◽  
Photographic Records

Three mixed flow impellers representing a wide range of design parameters were tested in a closed water loop to obtain correlations of the high-speed photographic records of the cavitation formations with various performance parameters. It was found that cavitation existed for all impellers at much higher values of NPSH than those associated with a finite drop in the impeller head rise. The cavitation formations in the vane channels of the impellers were observed to be cyclic in nature, whereas the cavitation near the leading edge of the vanes was more stable.

scholarly journals Numerical and experimental investigation of the pressure fluctuation in a mixed-flow pump under low flow conditions

2019 ◽  
Vol 234 (1) ◽  
pp. 46-57 ◽  
Author(s):  
Xi Shen ◽  
Desheng Zhang ◽  
Bin Xu ◽  
Ruijie Zhao ◽  
Yongxin Jin ◽  
...  
Keyword(s):  
Flow Field ◽  
Flow Rate ◽  
Flow Separation ◽  
Pressure Fluctuation ◽  
Static Pressure ◽  
Leading Edge ◽  
Low Flow ◽  
Flow Conditions ◽  
Mixed Flow ◽  
Flow Pump

In this paper, the large eddy simulation is utilized to simulate the flow field in a mixed-flow pump based on the standard Smagorinsky subgrid scale model, which is combined with the experiments to investigate pressure fluctuations under low flow conditions. The experimental results indicated that the amplitude of fluctuation at the impeller inlet is the highest, and increases with the reduction of the flow rate. The main frequencies of pressure fluctuation at the impeller inlet, impeller outlet, and vane inlet are blades passing frequency, while the main frequency at the vane outlet changes with the flow rate. The results of the simulation showed that the axial plane velocity at impeller inlet undergoes little change under 0.8 Qopt. In case of 0.4 Qopt, however, the flow field at impeller inlet becomes complicated with the axial plane velocity changing significantly. The flow separation is generated at the leading edge of the suction surface at t* = 0.0416 under 0.4 Qopt, which is caused by the increase of the incidence angle and the influence of the tip leakage flow. When the impeller rotates from t* = 0.0416 to t* = 0.1249, the flow separation intensified and the swirling strength of the separation vortex is gradually increased, leading to the reduction of the static pressure, the rise of adverse pressure gradient, and the generation of backflow. The static pressure at the leading edge of the impeller recovers gradually until the backflow is reached. In addition, the flow separation is the main reason for the intensification of the pressure fluctuation.

Performance Improvement of a Mixed-Flow Pump by Optimization Techniques

2011 ◽  
Author(s):  
Jin-Hyuk Kim ◽  
Chong-Hwi Jin ◽  
Kwang-Yong Kim
Keyword(s):  
High Efficiency ◽  
Stokes Equations ◽  
Leading Edge ◽  
Optimization Procedure ◽  
Latin Hypercube Sampling ◽  
Optimization Techniques ◽  
Mixed Flow ◽  
Impeller Blade ◽  
Flow Pump ◽  
Vane Diffuser

This paper presents an optimization procedure for high-efficiency design of a vane diffuser in a mixed-flow pump. Optimization techniques based on a radial basis neural network model are used to improve the performance of a vane diffuser in a mixed-flow pump. In flow analyses, three-dimensional Reynolds-averaged Navier-Stokes equations with the shear stress transport turbulence model are discretized by using finite volume approximations and solved on hexahedral grids to evaluate the efficiency as the objective function. The numerical results are validated through a comparison with experimental data for the head, power and efficiency. Latin-hypercube sampling method as design-of-experiments is used to generate the design points within the design space. In order to improve the efficiency of a mixed-flow pump, four variables defining the lean angle at diffuser vane tip span, the distance between trailing edge of impeller blade and leading edge of diffuser vane, the straight vane length ratio, and the diffusion area ratio are selected as design variables in the present optimization. As a result of the present study, the efficiency at the design point is remarkably enhanced through the design optimization.

scholarly journals Suppression of Secondary Flows in a Mixed-Flow Pump Impeller by Application of 3D Inverse Design Method: Part 1 — Design and Numerical Validation

1994 ◽  
Author(s):  
M. Zangeneh ◽  
A. Goto ◽  
T. Takemura
Keyword(s):  
Flow Field ◽  
Design Method ◽  
Secondary Flows ◽  
Inverse Design ◽  
Experimental Comparison ◽  
Suction Surface ◽  
Mixed Flow ◽  
Pump Impeller ◽  
Inverse Design Method ◽  
Flow Pump

This paper describes the design of the blade geometry of a medium specific speed mixed flow pump impeller by using a 3D inverse design method in which the blade circulation (or rVθ) is specified. The design objective being the reduction of impeller exit flow non-uniformity by reducing the secondary flows on the blade suction surface. The paper describes in detail the aerodynamic critria used for the suppression of secondary flows with reference to the loading distribution and blade stacking condition used in the design. The flow through the designed impeller is computed by Dawes viscous code, which indicates that the secondary flows are well suppressed on the suction surface. Comparison between the predicted exit flow field of the inverse designed impeller and a corresponding conventional impeller indicates that the suppression of secondary flows has resulted in substantial improvement in the exit flow field. Experimental comparison of the flow fields inside and at exit from the conventional and the inverse designed impeller is made in part 2 of the paper.

Sign in / Sign up

Export Citation Format

Share Document