Study of Sweepback Angles Criterion for Reusable Hypersonic
Vehicle 01-16-02-0010
This also appears in
SAE International Journal of Aerospace-V132-1EJ
At hypersonic speed, severe aerodynamic heating is observed, and temperatures are
too high to cool by radiation cooling; active cooling such as ablative cooling
is helpful in this situation. The Thermal Protection System (TPS) consists of a
layer of an ablative material, followed by an insulating material to lower the
temperature at the inside wall of the lifting body. The surface area
(considering the inside volume of the vehicle constant) of the TPS plays a vital
role in heat transfer to the vehicle and heat transferred through the vehicle
body. The minimum area sweepback angle (ΛArea-min) is the function of
the principal radius (R) and the ratio of the principal radii
of the forward bi-curvature stagnation surface
(R/r). The ΛArea-min = 80° is
obtained for R = 2 m and R/r
= 2. The aerothermal analysis of the lifting body is of fundamental interest
while designing the TPS. A Computational Fluid Dynamics (CFD) simulation of a
two-dimensional (2D) lifting body against thermally perfect air in a hypersonic
region (Mach number, M > 5) is carried out for
M = 5–9 to obtain a heat-transfer-minimized sweepback angle
(ΛHT-min), at which heat transfer to the vehicle is minimum. The
simulation was carried out at an altitude H = 35 km and zero
angle of attack for cruise conditions. Results show that ΛHT-min =
80° for all M (= 5–9, in this study) at all locations of
Sweepback Leading Edge (SBLE).