Analysis of the Turbulent Properties of Flow in Water-jet Pump Based on Wall-modeled Large-eddy Simulations
Scale-resolving simulations are potential for accurate predictions of unsteady flows.Wall-modeled large-eddy simulation(WMLES)has the advantages of wide application and relatively low computational cost.However,the application of WMLES to the turbulent flow in water-jet pump is limited.The WMLES based on the analysis of turbulent length scales is applied to simulate the flow fields in a prototype pump and a modified pump,and the simulated results are compared to the experimental results.The head rise and torque coefficients predicted by the WMLES agreed well with the experimental data.The analysis of the turbulent properties of flows in the pumps demonstrate that the WMLES is capable of reproducing the horseshoe vortices,corner vortices,tip concentrating vortices and tip leakage vortices that are difficult for the conventional Reynolds-Averaged Navier-Stokes(RANS)method to reproduce.The horseshoe and corner vortices of the modified pump are much weaker than those of the prototype pump,and the limiting streamlines of the modified pump are smoother that those of the prototype pump.The lower dissipation of energy caused by the weaker vortices led to the higher efficiency of the modified pump.The results demonstrated that the WMLES based on the analysis of turbulent length scales could be effectively applied to predict the performance and turbulent properties of flow in the water-jet pump,which can provide the data support for the improvement of water-jet pump.
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