LARGE EDDY SIMULATION OF NON-ISOTHERMAL FLOW IN ROTOR/STATOR CAVITY

Abstract

Corresponding author: ewa.tuliszka-sznitko@put.poznan.pl) The paper presents the 3D LES study of the non-isothermal transitional and turbulent flow in rotor/stator sealed cavity. Computations have been performed for the cavity of aspect ratio L=5, curvature parameter Rm=1.8, 3.0 and 5.0 and for the thermal Rossby numbers up to 0.2. Computations we based on the efficient pseudo-spectral Chebyshev-Fourier method. In Large Eddy Simulations we used a version of the dynamic Smagorinsky eddy viscosity model proposed by Meneveau [1996], in which the averaging is performed over the fluid particle pathline. INTRODUCTION The present study concerns the numerical prediction of the transitional and turbulent flows with heat transfer in an enclosed rotor/stator cavity. The problem is not only very interesting from the point of view of fundamental fluid mechanics but it is also a topic of practical importance. The flow in the rotating cavity is of great interest for the internal aerodynamics of engines, especially for the optimization of turbomachinery air-cooling devices. The experimental investigations in the rotating cavities are very difficult and expensive. In this situation, numerical simulations, particularly Direct Numerical Simulation (DNS) and Large Eddy Simulation (LES), which can deliver precise knowledge on the flow structure and temperature distributions in the rotating cavity become indispensable tools. Numerical modeling of the flow in the rotor/stator cavity turned out to be a difficult problem mostly due to the fact that in the cavity simultaneously exist areas of laminar, transitional and turbulent flow which are completely different in terms of flow properties. The present paper is devoted to a study of the turbulent and transitional flow with heat transfer in sealed rotor/stator cavities of aspect ratios 5 and curvature parameters1.8, 3.0 and 5.0. The cavity is heated from below and from the outer end-wall, whereas the rotor and the inner cylinder are cooled (Fig.1). The main motivation of our work is to analyze the properties of turbulence of the non-isothermal flow dominated by Coriolis and centrifugal forces. NUMERICAL MODELING The geometrical domain is presented in Fig.1. The upper disk rotates at a uniform angular velocity