LARGE EDDY SIMULATION OF THE EFFECTS OF INNER WALL ROTATION ON HEAT TRANSFER IN ANNULAR TURBULENT FLOW

Abstract

A large eddy simulation has been performed to investigate the effect of swirl on the heat and momentum transfer in an annular pipe flow with a rotating inner wall. The compressible filtered Navier-Stokes equations were solved using a second-order-accurate finite-volume method. Low-Mach-number preconditioning was used to enable the compressible code to work efficiently at low Mach numbers. A dynamic subgrid-scale stress model accounted for the subgrid-scale turbulence. A nonuniform grid in the radial direction yielded very accurate solutions using a reasonable number of grid points. The numerical results are summarized and compared with the experimental results of previous studies. The simulations indicated that the Nusselt number and the wall friction coefficient increased with increasing rotation speed of the wall. It was also observed that the axial velocity profile became flattened and turbulent intensities were enhanced due to swirl. This modification of the turbulent structures was closely related to the increase of the Nusselt number and the friction coefficient.

The authors are grateful to the National Science Foundation (NSF) and the U.S. Department of Energy under the NERI program for support through grants CTS-9806989 and DE-FG03-995F21924, respectively. The Iowa State High Performance Computing Center and University of the Minnesota Supercomputing Institute provided computational resources needed for this research.