Flowfield and Heat Transfer Characteristics in the LE-X Expander Bleed Cycle Combustion Chamber

Abstract

In Japan, a feasibility study of the new "LE-X" booster engine has been underway since 2005. One of the key technologies of the LE-X engine development is a regenerative cooling design to produce enough power to drive the turbopumps. The LE-X engine employs an elongated chamber design to pick up enough heat energy in the regenerative cooling channels. In the current study, a fully conjugated combustion and heat transfer simulation was performed to investigate the flow field and heat transfer characteristics for the regeneratively cooled combustion chamber of the LE-X engine. A three-dimensional Reynolds-averaged Navier-Stokes simulation was used to consider the injection and combustion processes of propellants on the hot-gas side, heat conduction in the chamber wall, and cooling channel flows. Details on the three-dimensional flow and thermal characteristics of the combustion chamber were clarified in the hot-gas and coolant side domains. In particular, significant thermal stratification was found to form in the radial direction of the cooling channel in the elongated cylindrical part of the chamber, which degraded the heat transfer and resulted in the highest wall temperature there. NomenclatureA = surface area C = heat capacity of solid C p = constant pressure heat capacity D = mass diffusivity  = dissipation rate of turbulence kinetic energy H = cooling channel height h = heat transfer coefficient l = length k = turbulence kinetic energy  = thermal conductivity Le = Lewis number  = dynamic viscosity Pr = Prandtl number p = pressure q = heat flux r = chamber radius s = normal distance Re = Reynolds number T = temperature t = time u = velocity x, y, z = Cartesian coordinates y + = normalized wall distance 2 Subscripts ave = average b = bulk property c = coolant cw = coolant side wall gw = hot-gas side wall int = interface peri = perimeter