Coupled analysis of hot-gas and coolant flows in LOX/methane thrust chambers

The analysis of the flow-behavior and the heat transfer characteristics in a regeneratively cooled thrust chamber is of paramount importance for the development of a high-performance liquid rocket engine and to guarantee its structural thermal design. The accurate analysis of such a problem can only be obtained by costly experiments or by complex numerical simulations, because of the three-dimensional shape of the cooling channels and of the coupling among evolution in hot-gas flow, coolant flow and wall heat transfer. However, parametric investigations of rocket thrust chambers thermal environment can also be efficiently made by accurate engineering tools. An example of the latter approach is provided in the present study: a computational procedure able to describe the typical hot-gas/wall/coolant environment of liquid rocket engines. This procedure provides a quick and reliable prediction of thrust-chamber wall temperature and heat flux. The coupled analysis is performed by means of an accurate CFD solver of the Reynolds-Averaged Navier-Stokes (RANS) equations for the hot-gas flow and a simplified “quasi-2D” approach, which widely relies on semi-empirical relations, to study the problem of coolant flow and wall structure heat transfer in the cooling channels. Numerical results, relevant to a sample engine fed with oxygen and methane are presented and discussed.