Work

Effect of forward-facing concavity on the aerodynamic and aerothermodynamic characteristics of an atmospheric Re-entry vehicle

Year: 2024

Type: article

Abstract: Aerodynamic heating and drag remain the two foremost factors to consider in the design of a re-entry vehicle. Mitigating the aero-heating effects is paramount for re-entry vehicles decelerating higher up in the atmosphere at hypersonic speeds . Re-entry vehicles use either propulsive forces, drag, or a combined effect of both to their advantage in order to dissipate speed. Furthermore, the ballistic coefficient, another critical parameter in determining the re-entry trajectory, is constantly optimized to lower values, meaning optimal re-entry with reduced aerothermal loads imposed upon the vehicle. The current computational study involves a design modification of the existing ORION CEV crew module, introducing a concavity on the heat shield of the re-entry vehicle—the forward-facing concavity. Six 2-dimensional spline curves were constructed to create six concavities at the nose of the vehicle based on the d/D ratios, where d is the height of the concavity measured from the axis of symmetry, and D is the depth of the concavity measured from the nose of the baseline model. The effect of these forward-facing concavities on aerodynamic and thermodynamic parameters , such as drag coefficient , ballistic coefficient, mean shock standoff distance (MSSD), and heat flux distribution, is investigated at varying Mach numbers of 1.4, 3, 6, and 7 at 0° angle of attack . Furthermore, the monostability characteristics have been evaluated as well. From the analyses, comparing with the baseline model, M6 (d/D = 2.9) has the highest increment in drag of about 15 %. Model M3 (d/D = 0.97) has the maximum increment in MSSD of about 52.2 %. At higher Mach numbers , there is a reduction in nose heat flux at the cost of an increased peak. There is a 6 % reduction in heat flux over the entire heat shield for M6.

Source: Results in Engineering

DOI: 10.1016/j.rineng.2024.103080