Numerical Simulation of Hot-Gas Side Heat Transfer Enhancement in Thrust Chambers by Wall Ribs

Abstract

uxes. Heat transfer accurate prediction is one of the key features for the development of these engines, especially in the case of expander cycle feed system. In the present study, hot-gas side heat transfer enhancement due to ribbed walls in an expander cycle engine thrust chamber is analyzed by means of a Reynolds-Averaged Navier-Stokes (RANS) equations solver. As a validation of the solver, a ribbed wall experimental test case is reproduced to assess the capability of the solver to properly capture thermal boundary layer and heat transfer enhancement. In this test case, heat enhancement is quantied by measuring water coolant temperature increase along the duct. Then a simplied coupling procedure is adopted to compare numerical simulation against experimental data. Finally an expander cycle engine thrust chamber is studied focusing on heat transfer enhancement due to ribbed walls, compared to the smooth wall case. In this study the capability of the solver to be employed as a design tool for wall ribbed thrust chambers is shown. The adequate understanding and accurate prediction of heat transfer characteristics, heat pick-up and wall temperature distribution in the thrust chamber are considered key features for the development of high performance engines, especially in the case of expander cycle. In fact, in these cycles the driving power for the turbo-pumps comes from the fuel used as a coolant in the regenerative cooling circuit. Expander cycle engines are an attractive solution for upper stage and in-space propulsion because of their capability for multiple restarts and throttling. They have the simplest conguration among the pump-fed cycles because