COOLING OF AEROSPACE PLANE USING LIQUID-HYDROGEN AND METHANE

This work studies the active cooling for aerospace plane, using liquid hydrogen and liquid methane. The ascending optimized trajectory to mi nimize the heat load in the hypersonic part is used to perform the stu dy. The study includes the cooling for the stagnation point, the leadi ng edges for wings and engine and other parts of the aerospace plane t hat are close to the leading edges, Laminar flow for the stagnation po int and both laminar and turbulent flow for the leading-edge heating h ave been considered. The amount of heat rate (total, radiative, and co nvective) and the mass of liquid coolant needed for cooling are calcul ated. A design of minimum inlet-outlet areas for the amount of liquid needed for cooling is made with the consideration of the coolant's phy sical constraints in liquid and gaseous states, The study shows that t he ratio of masses of coolant to the initial total mass (initial total mass of the vehicle including fuel and coolant masses) are in the lim it of the reachable range, which requires about 20% or less of initial total mass for cooling in the worst case. Comparison of liquid hydrog en and liquid methane shows that liquid hydrogen is a clearly superior candidate for coolant and it saves 10% of the initial total mass as c ompared to methane, The study shows that there are no fundamental barr iers for the cooling system of the vehicle in terms of its coolant mas s and area size for coolant passage.