Study of Thermochemical Non-equilibrium and Sensor Cavity Geometry in Hypersonic Flow

Abstract

This work presents a computational investigation of the influence of geometric configurations within a hypersonic flow field on optical distortion, with a particular focus on the effects of window deformation and the role of thermochemical modeling compared to perfect gas assumptions. Turbulent RANS and conjugate heat transfer were used to model three 3D geometries in US3D, an unstructured-grid finite volume computational fluid dynamics (CFD) solver. The three investigated geometries are a flat plate with a flush-mounted sensor, an open cavity with a length-to-depth ratio of 2, and a closed cavity with a length-to-depth ratio of 16. The data demonstrate that the flat plate configuration has the best optical performance and that the closed cavity has the worst. Additionally, the inclusion of thermochemistry in the flow simulation results in a more pessimistic outlook on image quality compared to the perfect gas model. The results document optical distortion for several different geometries with and without thermochemical modeling within hypersonic flow that can inform future design decisions and research.