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Numerical simulation of cavitating two-phase gas-liquid three dimensional flow in a duct of varying cross-section based on homogenous mixture model

The paper presents a numerical method to simulate two-phase turbulent cavitating flows in ducts of varying cross-section usually faced in engineering. The method is based on solution of two-phase Reynolds-averaged Navier-Stokes equations of two-phase mixture. The numerical method uses artificial compressibility algorithm extended to unsteady flows with dual-time technique. | . Vietnam Journal of Mechanics, VAST, Vol. 28, No. 3 (2006), pp. 134- 144 NUMERICAL SIMULATION OF CAVITATING TWO-PHASE GAS-LIQUID THREE-DIMENSIONAL FLOW IN A DUCT OF VARYING CROSS-SECTION BASED ON HOM OGENOUS MIXTURE MODEL NGUYEN THE Due Institute of Mechanics, Vietnamese Academy of Science and Technology Abstract. The paper presents a numerical method to simulate two-phase turbulent cavitating flows in ducts of varying cross-section usually faced in engineering. The method is based on solution of two-phase Reynolds-averaged Navier-Stokes equations of two-phase mixture. The numerical method uses artificial compressibility algorithm extended to unsteady flows with dual-time technique. The discreted method employs an implicit, characteristic-based upwind differencing scheme in the curvilinear grid systems. Numerical simulation of an unsteady three-dimensional two-phase cavitating flow in a duct of varying cross-section with available experiment was performed. The unsteady important characteristics of the unsteady flow can be observed in results of numerical simulation. Comparison of predicted results with experimental data for time-averaged velocity and phase fraction are provided. 1. INTRODUCTION It is highly desirable for high-speed hydraulic machinery and equipment to provide reliable operation over a wide range of operating conditions. In the estimation of performance, the existence of cavitating flow, which is considered to be high-speed gas-liquid two-phase fl.ow, is a very important factor. Studies dealing with cavitation modeling through the computation of the Navier-Stokes equations have emerged in the recent years. These studies may broadly be classified into two categories: interface tracking models and homogeneous equilibrium fl.ow models. In the first category, the liquid-vapor interface is tracked and grid is often regenerated iteratively to conform to the cavity region. Examples of this tracking method can be found in [1] and [2] . However, .