Research on a Full Three-Dimenional Inverse Method for the Mixed-Flow Pump Runner

2002 ◽  
Author(s):  
Honggang Fan ◽  
Naixiang Chen ◽  
Lin Yang ◽  
Zhaohui Xu ◽  
Lunfu Qu ◽  
...  
Keyword(s):  
Inverse Method ◽  
Three Dimensional ◽  
New Method ◽  
Periodic Flow ◽  
Mean Flow ◽  
Mixed Flow ◽  
Three Dimensional Flow ◽  
Dimensional Flow ◽  
Blade Shape ◽  
Flow Pump

In this paper, a full three-dimensional inverse method for the design of mixed-flow pump runner is described. The three-dimensional flow in the runner is decomposed into a tangential mean flow and a tangential periodic flow. The blades are represented by superposition of vortices and sources on the blade mean surface, and the blade mean surface is determined by the inverse method. In this method, the distribution of the circumferentially mean swirl VRθ on the meridional geometry of the runner is prescribed and the corresponding blade shape is computed iteratively. The new method is applied to the design of a mixed-flow pump runner and the result is satisfactory.

Improved κ-ɛ Modelling of Impeller Flow Performance of a Mixed-Flow Pump under off-Design Operating States

1993 ◽  
Vol 207 (4) ◽  
pp. 219-229 ◽  
Author(s):  
S M Fraser ◽  
Y Zhang
Keyword(s):  
Stokes Equations ◽  
Three Dimensional ◽  
Careful Analysis ◽  
Navier Stokes ◽  
Mean Flow ◽  
Mixed Flow ◽  
Navier Stokes Equations ◽  
Flow Through ◽  
The Mean ◽  
Flow Pump

Three-dimensional turbulent flow through the impeller passage of a model mixed-flow pump has been simulated by solving the Navier-Stokes equations with an improved κ-ɛ model. The standard κ-ɛ model was found to be unsatisfactory for solving the off-design impeller flow and a converged solution could not be obtained at 49 per cent design flowrate. After careful analysis, it was decided to modify the standard κ-ɛ model by including the extra rates of strain due to the acceleration of impeller rotation and geometrical curvature and removing the mathematical ill-posedness between the mean flow turbulence modelling and the logarithmic wall function.

Quantitative measurements of three-dim ensional structures in the wake of a circular cylinder

1994 ◽  
Vol 270 ◽  
pp. 277-296 ◽  
Author(s):  
Hussein Mansy ◽  
Pan-Mei Yang ◽  
David R. Williams
Keyword(s):  
Circular Cylinder ◽  
Secondary Flow ◽  
Three Dimensional ◽  
Streamwise Vortices ◽  
Mean Flow ◽  
Near Wake ◽  
Three Dimensional Flow ◽  
Primary Flow ◽  
Flow Component ◽  
Dimensional Flow

The fine scale three-dimensional structures usually associated with streamwise vortices in the near wake of a circular cylinder have been studied at Reynolds numbers ranging from 170 to 2200. Spatially continuous velocity measurements along lines parallel to the cylinder axis were obtained with a scanning laser anemometer. To detect the streamwise vortices in the amplitude modulated velocity field, it was necessary to develop a spatial decomposition technique to split the total flow into a primary flow component and a secondary flow component. The primary flow is comprised of the mean flow and Strouhal vortices, while the secondary flow is the result of the three-dimensional streamwise vortices that are the essence of transition to turbulence. The three-dimensional flow amplitude increases in the primary vortex formation region, then saturates shortly after the maximum amplitude in the primary flow is reached. In the near-wake region the wavelength decreases approximately like Re−0.5, but increases with downstream distance. A discontinuous increase in wavelength occurs below Re = 300 suggesting a fundamental change in the character of the three-dimensional flow. At downstream distances (x/D = 10-20), the spanwise wavelength decreases from 1.42D to 1.03D as the Reynolds number increases from 300 to 1200.

Performance of a Mixed Flow Pump with Varying Tip Clearance: Part 1

1996 ◽  
Vol 210 (4) ◽  
pp. 305-318 ◽  
Author(s):  
T K Saha ◽  
S Soundranayagam
Keyword(s):  
Angular Momentum ◽  
Flow Field ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Flow Reversal ◽  
Tip Clearance ◽  
Mixed Flow ◽  
Three Dimensional Flow ◽  
Specific Speed ◽  
Flow Pump

Measurements of the three-dimensional flow field entering and leaving a mixed flow pump of non-dimensional specific speed k = 1.89 [ Ns = 100 r/min (metric)] are discussed as a function of flowrate. Flow reversal at inlet at reduced flows is seen to result in abnormally high total pressures in the casing region, but causes no noticeable discontinuities on the head-flow characteristics. Inlet prerotation is associated with the transport of angular momentum by the reversal eddy and begins with the initiation of flow reversal.

Explicit Algebraic Reynolds-stress Modeling of Pressure-induced Separating Flows in the Presence of Sidewalls

2021 ◽  
Author(s):  
Abdelouahab Mohammed Taifour ◽  
Julien Weiss ◽  
Louis Dufresne
Keyword(s):  
Reynolds Stress ◽  
Test Section ◽  
Three Dimensional ◽  
Wind Tunnel Test ◽  
Shear Stresses ◽  
Mean Flow ◽  
Flow Topology ◽  
Three Dimensional Flow ◽  
Dimensional Flow ◽  
Good Agreement

Abstract RANS approach is used to simulate the steady state of a family of pressure-induced turbulent separation bubbles in the presence of sidewalls. Different turbulence models are employed with a specific emphasis on the BaSeLine Explicit Algebraic Reynolds Stress Model (BSL-EARSM) and the simulations are compared with experimental data. The separation and reattachment of a flat-plate turbulent boundary layer is generated through a combination of adverse and favorable pressure gradients (APG-FPG) by numerically reproducing the geometry of the wind-tunnel test section used for the experiments. Three cases are considered, a large (LB) and a medium (MB) bubble presenting mean backflow, and a small bubble (SB) without mean-flow reversal. This is achieved by varying the streamwise position of the APG/FPG transition. Good agreement between the BSL-EARSM-computed solutions and the experimental results are obtained for wall-pressure and skin-friction distributions on the centerline plane of the test section as well as for the overall three-dimensional flow topology. However, both detachment and reattachment are predicted too early and the bubble length is slightly overestimated for Cases LB and MB. For Case LB, the streamwise Reynolds stress is estimated fairly well but its production is somewhat delayed. Normal and shear stresses are in good agreement with the experiments in the upstream part of the bubble but are significantly over-estimated in the reattachment region. The k ?? ! Shear-Stress Transport (SST) model with the so-called reattachment modification performs better than the other tested linear-eddy-viscosity models but it is still unable to reproduce accurately the three-dimensional flow topology even for the 'simplest' case SB. Overall, the results suggest that BSL-EARSM is the most suitable turbulence model for this flow configuration.

Unsteady Three-Dimensional Flow Phenomena in an Axial Flow Pump at Different Operating Points

2008 ◽  
Author(s):  
Friedrich-Karl Benra ◽  
Hans Josef Dohmen
Keyword(s):  
Three Dimensional ◽  
Axial Flow ◽  
Flow Fields ◽  
Operating Conditions ◽  
Three Dimensional Flow ◽  
Design Point ◽  
Part Load ◽  
Dimensional Flow ◽  
Axial Flow Pump ◽  
Flow Pump

In highly loaded axial flow pumps considerable changes of the flow behavior are known when altering the flow rate from design point operation to part load operation. The flow structure which is changing from stable operating conditions to stalled flow conditions has been investigated experimental by Kosyna and Stark. The measured results are compared to results obtained by numerical simulations in a previous paper of the authors. Time dependent three dimensional flow fields in this axial flow pump have been investigated by unsteady Reynolds averaged Navier-Stokes simulations. The time resolved flow fields are compared to the time averaged results of the measurements for the design point and also for part load operating conditions. The change in the vortex structure induced by the tip leakage flow is investigated in detail for different conditions of operation. Also the part load recirculation vortex dominating the rotor tip flow at deep stall conditions as well as the cross passage vortex is visualized by evaluating the numerical results.

Modelling of Incompressible Three-Dimensional Flow in Rotating Turbomachinery Passages

2002 ◽  
Author(s):  
C. Cravero ◽  
A. Satta ◽  
M. Marini
Keyword(s):  
Compressible Flows ◽  
Incompressible Flows ◽  
Three Dimensional ◽  
Inviscid Flow ◽  
Mixed Flow ◽  
Three Dimensional Flow ◽  
Pump Impeller ◽  
Preconditioning Technique ◽  
Cfd Method ◽  
Flow Pump

A CFD method, previously developed by the authors for compressible flows, has been modified through a preconditioning technique to account for purely incompressible flows. Such a code is used to compute three-dimensional flows in a mixed flow pump impeller at design and off-design conditions. The results of the inviscid flow approach are critically discussed by comparison to available experimental data.

Numerical Simulation of Three Dimensional Flow in Large Mixed-Flow Pump System

2011 ◽  
Author(s):  
Fan Yang ◽  
Chao Liu ◽  
Fangping Tang
Keyword(s):  
Pressure Distribution ◽  
Model Test ◽  
Static Pressure ◽  
Three Dimensional ◽  
Mixed Flow ◽  
Three Dimensional Flow ◽  
Pump System ◽  
Static Pressure Distribution ◽  
Calculation Results ◽  
Flow Pump

The three-dimensional flow inside a mixed-flow pump system was simulated by using CFX software. The Shear Stress Transport turbulent equation which combined k-ε and k-ω turbulent model was applied. The flow field in volute and discharge passage of the pump system was obtained and the hydraulic performances of the pump system were predicted. The velocity and pressure distribution in pump system were analyzed. From the calculation results it is evident that the flow in the double helix volute passage is a spiral movement combining axial and rotary flow; the static pressure distribution in the volute is symmetric; the uniformity of axial velocity distribution and velocity-weighted average swirl angle at the outlet section are relatively low; and static pressure distribution on pump blade surface is regular with higher static pressure on pressure side and lower one on the suction side. The axial forces decrease gradually with the decrease of lifting head and the radial forces decrease first and then increase. A model test of the pump system was conducted to verify the calculation results. The pressure fluctuation at certain sections of the pump system was measured from the model test. A good agreement was found for lifting head between calculated and measured results. While the deviation of the efficiency between calculated and measured results does exist in non design points which need to be improved.

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