TURBULENT HEAT TRANSFER NEAR THE REATTACHMENT OF FLOW DOWNSTREAM OF A SUDDEN PIPE EXPANSION

Abstract
Numerical predictions are obtained for the turbulent flow and heat transfer downstream from a sudden expansion in a circular pipe. A full Reynolds stress model is used to close the time-averaged Navier-Stokes equations, with an algebraic model for the thermal fluxes. The models account for the low Reynolds number effects in the wall region and thus avoid use of the conventional wall functions. The predicted Nusselt number distribution along the heated wall especially in the reattachment region is in very good agreement with available measurements.