Influence of chemical models on heat flux for EXPERT and Orion capsules

Abstract

The computation of heat flux on two current re-entry capsules, European eXPErimental Reentry Testbed (EXPERT) and Orion, has been carried out by a direct simulation Monte Carlo code (DS2V) and by a computational fluid dynamic code (H3NS) in transitional regime, considering both non-reactive and fully catalytic surface. These capsules have been chosen for this analysis because they have been characterized by completely different shapes and re-entry trajectories. DS2V and H3NS use the Gupta and the Park chemical models, respectively. The results showed that the heat flux predicted by DS2V is always higher than that predicted by H3NS. Therefore, a sensitivity analysis of the chemical models on the heat flux has been carried out for both capsules. More specifically, the Park model has been implemented in DS2V as well. The results showed that DS2V and H3NS compute a different chemical composition both in the flow field and on the surface, even when using the same chemical model (Park); therefore, the different results obtained from the two codes can be attributed mostly to the different methodology used in handling all chemical processes.

IXV post-flight reconstruction and analysis of the aerothermodynamic measurements along the rarefied portion of the reentry trajectory

“…The chemical composition differences are thought to be mostly due to the difference in the shock layer profiles (see Figures 29b and 29d). In addition, Morsa et al [46] observed significant discrepancies between the DSMC and CFD chemical compositions and heat flux with the same chemical model. They attributed this deviation to the methodologies for handling the chemical processes that are different for both approaches.…”

Rarefied aerodynamic characteristics of aero-space-planes: a comparative study of two gas–surface interaction models

“…A sensitivity analysis has been carried out for both DS2V and DS3V, in terms of the global aerodynamic coefficients computed at an intermediate angle of attack (α = 25 deg). The present analysis follows a similar procedure [25] in which the influence of the number of collision and sampling cells was evaluated on the DS2V results. The test case considered in [25] Fig.…”

“…The present analysis follows a similar procedure [25] in which the influence of the number of collision and sampling cells was evaluated on the DS2V results. The test case considered in [25] Fig. 4 shows the re-emission lobes from the Maxwell and the CLL models at the intermediate angle of incidence of ϑ = 40 deg.…”