COUPLED NUMERICAL ANALYSIS OF VARIABLE CROSS-SECTION COOLING CHANNELS IN LOX/METHANE ROCKET ENGINES

A three-dimensional coupled heat transfer model is applied for numerical studies of turbulent flow and heat transfer of methane in variable cross-section cooling channels of LOX/methane rocket engines at a supercritical pressure. The results indicate that when the coolant flows through an abruptly expanding structure, the fluid flow velocity suddenly drops, and the average temperature of the fluid reaches a peak. This effect will increase with increase of the sudden contraction/expansion area ratio. After the coolant flows through the expansion structure, the vortices counteract the effect of the secondary flow generated by the centrifugal force in the convergent section of the thrust chamber. This will reduce the coolant helicity here, finally resulting in low convection heat transfer. Generally speaking, the contraction structure has a certain improvement of the heat transfer of coolant in the cooling channels. Through sensitivity analysis, the variable cross-section cooling channels whose contraction/expansion area ratio varies between 1.25 and 1.5 have the most engineering application under the cases discussed in this paper.