Tool for Rapid Transient Transpiration-Cooled Reentry Simulation

Abstract

This paper presents a numerical model intended for a system study of transpiration cooled thermal protection systems. The code PIRATE (Porous Impulse Response Analysis for Transpiration cooling Evaluation) enables rapid transient calculations for thermal protection systems of hypersonic flight vehicles. In the code, semi-empirical aerodynamic correlations are employed. However, the code could also be used by applying higher fidelity inputs from CFD calculations for more complicated vehicle geometries. The wall temperature distribution is calculated by utilising the thermal impulse and step responses of porous media, increasing the calculation speed significantly. A heat flux balance is considered for a one-dimensional porous material. The code is validated with experimental data of plasma wind tunnel tests and the SHEFEX II flight experiment. The transient heating of a flat plate model in a steady state flow condition in the L2K plasma wind tunnel is assessed for both un-cooled and transpiration cooled cases. The SHEFEX II flight simulation accounts for transient external flow conditions * Post-doctoral research assistant, Hypersonics group, Oxford Thermofluids Institute, AIAA Member.

Performance of Transpiration-Cooled Heat Shields for Reentry Vehicles

“…The different validation cases demonstrate that the numerical model developed matches experimental data closely and agrees with experimental measurements to within 10 %. The relevant effects occurring during transpiration cooled hypersonic flight, i. e. transient heating, local cooling through blowing, and downstream film coverage, are replicated within acceptable accuracy [45]. The validation cases correspond to set-ups where lateral conduction is comparably small and hence a one-dimensional approach captures the relevant effects.…”

“…Figure 2 presents an outline of the code which is described in detail in Ref. [45]. The code uses mostly analytical or low-cost numerical schemes and hence achieves short computation times which allow for a large amount of calculations in a reasonable time.…”

Numerical Simulation of Transpiration Cooling for a High-Speed Vehicle with Substructure

“…The PIRATE numerical code [8] calculates the transient temperature response for a one-dimensional porous material subjected to aerodynamic surface heating. By relying on a method based on impulse response convolution, significantly faster computation times are possible, providing the opportunity to conduct optimization studies for various flight trajectories and geometries.…”

“…In addition, it should be noted that the faster computation times are achieved by calculating the surface and backside temperatures directly, and the temperatures at different intermediate locations through the material are not available without additional computations. This approach is detailed further by Hermann et al [8].…”

“…Both of these models considered an adiabatic backside and did not consider the effects of the integrated heat load to the substructure of the vehicle. Hermann et al [8] applied the one-dimensional porous impulse response analysis for transpiration cooling evaluation (PIRATE) numerical code to conduct systems studies of transpiration cooling for a blunt cone. This analysis considered radiation coupling between the transpiration-cooled skin and the substructure, but it assumed that the substructure was at constant temperature.…”