Session: 10-06-02: Industrial Flows - II

Paper Number: 94484

94484 - Application of Wray-Agarwal One-Equation Turbulence Model to Industrial Flows With Large Curvature 

Turbulence modeling plays an important role in accurate prediction of turbulent fluid motion in Computational Fluid Dynamics (CFD) simulations using the Reynolds-Averaged Navier-Stokes (RANS) equations. A new one-equation Wray-Agarwal (WA) turbulence model has been recently developed to improve the prediction of non-equilibrium turbulent flows with large separation and curvature [1]. In this paper, the WA turbulence model is employed to simulate the internal turbulent flow in a U-bend and a centrifugal pump. The computed results are compared with the experimental data. The results obtained from four other commonly used turbulence models, namely the one-equation Spalart-Allmaras (SA), two-equation standard k-ε, RNG k-ε, and SST k-ω turbulence models are also compared. In case of flow in the U-bend, the experimental data is obtained from Magnetic Resonance Velocimetry (MRV) [2]. The computed results for the velocity and helicity iso-surfaces using the WA turbulence model are consistent with the experimental data and there is only small difference in the exit part of the test section; WA model predictions are better than all other models for all flow quantities of interest.  For the case of flow in a centrifugal pump [3], the computations again show that the WA model can be used to accurately compute the energy performance of centrifugal pump under full range of operating conditions and gives higher accuracy than other models. Overall, the WA model shows more closer agreement to the experimental data and gives more uniform flow field in the impeller region compared to that predicted by other four turbulence models. The control of undamped eddy viscosity variable R (= k/ω) in WA model does not allow the overestimation of turbulent kinetic energy and turbulent eddy frequency obtained with other models, which leads to its advantage in accurate prediction of both internal and external flow characteristics of centrifugal pump. For both the test cases of flow in U-bend and centrifugal pump, the computed results with five different turbulence models show that the WA turbulence model gives the highest accuracy in predicting the complex 3-D turbulent characteristics of the flow with large curvature in a U-bend and a centrifugal pump. Furthermore, being a one equation model, it is very efficient. 

[1]  Wray, T. and Agarwal, R. K.,  "Low-Reynolds-Number One-Equation Turbulence Model Based on k-ω Closure," AIAA Journal, 2015, 53(8): 2216-2227.

[2]  Benson, M., Banko, A., Elkins C, et al., "The 2019 MRV Challenge: Turbulent Fow through a U-bend. Experiments in Fluids, 2020, 61(6): 1-17.

[3]  Wang, K., Liu, H., Yuan, S., et al.,"Numerical Simulation and Stereo PIV Test of Inner Flow in a Double Blades Pump," ASME-JSME-KSME 2011 Joint Fluids Engineering Conference, American Society of Mechanical Engineers Digital Collection, 2011: 321-329.

Presenting Author: Ramesh Agarwal Washington Univ

Presenting Author Biography: Prof. Ramesh K. Agarwal is the William Palm Professor of Engineering in the department of Mechanical Engineering & Materials Science in Washington University in St. Louis. He is a Fellow of ASME.

Authors:

Ramesh Agarwal Washington Univ