Aerodynamic optimisation of a hypersonic reentry vehicle based on solution of the Boltzmann-BGK equation and evolutionary optimisation

Over the past decade there has been a surge in the interest, both academic and commercial, in supersonic and hypersonic passenger transport. This paper outlines an original approach for solving the problem of optimal design and configuration of a space vehicle operating in rarefied hypersonic flow. The approach utilises a novel flow solver based on the solution of the Boltzmann-BGK equation. For the first time this solver has been coupled to an evolutionary optimiser to assist in navigation of the unfamiliar hypersonic design space. The Boltzmann-BGK solver is rigorously tested on a number of examples and is shown to handle rarefied gas dynamics examples across a range of length scales. The examples, presented here for the first time, include: a Riemann-type gas expansion problem, drag prediction of a nano-particle and supersonic flow across an aerofoil. Finally the solver is coupled to the evolutionary optimiser Modified Cuckoo Search approach. The coupled solver-optimiser design tool is then used to explore the optimum configuration of the fore body of a generic space reentry vehicle under a range of design conditions. In all examples considered the flow solver produces valid solutions. It is also found that the evolutionary optimiser is successful in navigating the unfamiliar design space. Crown Copyright (C) 2017 Published by Elsevier Inc. All rights reserved.