Hypervelocity aeroheating measurements in wake of Mars mission entry vehicle

Abstract

Detailed measurements of aerodynamic heating rates in the wake of a Mars-Pathfinder configuration model have been made. Heating data were obtained in a conventional wind tunnel, the NASA LaRC 31" Mach 10 Air Tunnel, and in a high-enthalpy impulse facility, the NASA HYPULSE expansion tube, in which air and CO 2 were employed as test gases. The enthalpy levels were 0.7 MJ/kg in the Mach 10 Tunnel, 12 MJ/kg at Mach 9.8 for HYPULSE CO 2 tests and 14 MJ/kg at Mach 7.9 for HYPULSE air tests. Wake heating rates were also measured on three similar parametric configurations, and forebody heating measurements were made in order to facilitate CFD comparisons. The ratio of peak wake heating to forebody stagnation point heating in the Mach 10 Tunnel varied from 7% to 15% depending on the freestream Reynolds number. In HYPULSE, the ratio was ~5% for both air and CO 2 . It was observed that an increase in the ratio of forebody corner radius to nose radius resulted in a decrease in peak wake heating, and moved the peak closer to the base of the forebody. The wake flow establishment process in HYPULSE was studied, and a method was developed to determine when the wake has become fully established. BACKGROUND

Mechanisms of Coupled Vibrational Relaxation and Dissociation in Carbon Dioxide

“…The heat flux calculated using expression as well as different contributions to the heat flux are presented in Figure . First of all, we emphasize that the surface Fourier flux is in a good agreement with the stagnation point heating of 8MW/m 2 measured in refs and (see the black point with its error bar in Figure b).…”

“…The selected boundary conditions are the surface and edge temperatures, T w = 700 K and T e = 4555 K, the pressure, p e = 1.269 × 10 5 Pa, the inverse of the residence time in the boundary layer, β = 1.283 × 10 5 s –1 , the edge composition CO 2 % = 22.6662, CO % = 41.5502, O 2 % = 5.6685, O % = 30.115, C % = 10 –4 . This test case (except T w ) corresponds to the experiment of Hollis ,, conducted in the HYPULSE facility under the following free stream conditions: velocity is 4788 m/s, density is 5.738 × 10 –3 kg/m 3 , pressure is 1182 Pa, and temperature is 1090 K. The surface is assumed noncatalytic according to the conditions of experiment. It is worth noting that studying a partially catalytic surface is of particular interest for aerospace applications.…”

“…Peculiarities of nonequilibrium vibrational distributions, mixture vibrational energy and the resulting heat flux are discussed; the surface heat flux is compared to that measured experimentally. 30,31…”

State-Resolved Dissociation and Exchange Reactions in CO2 Flows

“…The boundary conditions used in our study correspond to the experiment of Hollis − conducted in the HYPULSE facility under the following free stream conditions: velocity is 4788 m/s, density is 5.738 × 10 –3 kg/m 3 , pressure is 1182 Pa, and temperature is 1090 K. Measurements have been carried out on the surface of a 70-deg sphere-cone model using the thin-film temperature resistance gauges. , The free stream and postnormal shock conditions were then reconstructed numerically. In the present study, the boundary layer external edge conditions are those obtained for the abovementioned free stream conditions by Reynier with the 2D TINA code.…”

Survey of high-enthalpy shock facilities in the perspective of radiation and chemical kinetics investigations

“…HYPULSE is also used for aerothermodynamics testing related to atmospheric entry. Most of the work done for this purpose has been focused to duplicate Mars [127][128][129] for investigating the wake flow of the capsule. Wake and forebody heating rates were measured.…”