Numerical Analysis of Methane Flow in Curved Cooling Channels

Flow modeling in regeneratively cooled rocket engines is a challenging task because of the high wall temperature gradient, the high Reynolds number, the high aspect ratio of the channel cross section and the curved geometry. If coolant is methane, a further complication is its near-critical operating condition. In this thermodynamic regime large changes of the fluid properties can greatly influence the coolant flow field and the heat transfer. For this reason the adopted Reynolds Averaged Navier-Stokes solver for real fluids has been validated against experimental data of near-critical-hydrogen flow in circular duct, and the effect of the variable properties on the one-equation SpalartAllmaras turbulence model is investigated. Then numerical simulations of near-critical methane flow field in asymmetrically heated rectangular channel with high aspect ratio and strong wall temperature differences are carried out for curved channels (heated both on the convex and concave side). Emphasis is given to the most critical case in terms of cooling performance, that is, curved channel heated on the convex side.