Large Eddy Simulations of Fully Developed Flow Through a Spanwise Rotating Infinite Serpentine Passage

Abstract

The ability to predict turbine blade heat transfer is an important problem and is strongly dependant on the ability to predict the turbulent flow-field. Turbine blade internal coolant flow is often subjected to strong curvature and possibly rotational effects, two flow characteristics that make RANS modeling efforts difficult. An assessment of Large Eddy Simulation (LES) has been conducted for a flow with strong streamline curvature and rotational effects. Simulations of fully developed turbulent flow in an isothermal, smooth-wall, serpentine passage have been performed and compared to the Direct Numerical Simulation (DNS) data of Laskowski (2004). The flow is periodic in the stream-wise and span-wise directions and simulations were conducted for span-wise rotation numbers Rob = 0.0 and Rob = 0.32. The geometry has dimensions 12πδ × 2δ × 3πδ, in the stream-wise, wall-normal and span-wise directions, respectively, where δ is half the passage height. The inner radius of the bends is δ. The Reynolds number based on the bulk velocity and H = 2δ is Reb = 5600. A kinetic-energy conserving, finite-volume, collocated-mesh scheme (Felten and Lund, 2006) is applied to treat the streamwise and wall-normal directions, while Fourier collocation is used in the spanwise direction. A third-order Runge-Kutta explicit marching scheme is used to advance the solution in time and the pressure Poisson Equation is solved using a multigrid technique. The LES results are presented and close agreement with the DNS is noted for both the stationary and rotating cases.