Improved Modelling of Radiative Heating Effects for Hypersonic Planetary Entry Vehicles

从工程的角度来看，在载人火星任务可行之前，需要对大气层进入所涉及的物理学有更深入的了解。与这一目标相关的一个突出问题是由高温二氧化碳引起的辐射加热的精确建模。这最近被确定为流动状态下进入飞行器的一个重要热负荷来源，传统的辐射加热不是一个问题。然而，目前的预测模型已经证明在几个方面与实验不一致。迄今为止完成的工作是开发一个实验设施，可以模拟大气进入时的空气热力学流动条件。所提议的设备被证明能够达到期望的流动条件，产生高质量的结果，并展示了独特的研究潜力的冲击层辐射研究。本文的主要目的是对模拟火星气体混合物中波红外辐射的辐射加热进行实验研究。正如将要讨论的，这一领域存在着重大的不确定性- -与今后的特派团有关。这项工作将证实以前的结果，产生新的数据，并提出改进现有的建模工具，这将使车辆辐射加热的预测更有信心。在支持这些目标的时间已经花在开发新的T6铝激波管（AST）。该设施建成后将成为欧洲焓值最高的地面测试设施，为空气热力学效应的研究提供了独特的能力。为确保该资源的潜力得到充分发挥，我们进行了一系列的模拟练习，以确定所需的性能是可以达到的。对该设施的最终能力有了更深入的了解，从而可以对该领域的当前文献进行更务实的审查，并计划未来的工作来利用激波管的优势。

A greater understanding of the physics involved in atmospheric entry is required before a manned mission to Mars is viable from an engineering perspective.An outstanding problem relevant to this goal is the accurate modelling of radiative heating due to high-temperature CO2. This has recently been identified as a significant source of heat load on an entry vehicle in a flow regime where traditionally radiative heating is not an issue. However, current predictive models have been shown to disagree with experiment on several fronts.The work completed to date to develop an experimental facility allows the simulation of the aerothermodynamic flow conditions present during atmospheric entry. The proposed facility is shown to be capable of achieving the desired flow conditions, of producing high-quality results, and of demonstrating unique research potential for shock-layer radiation studies.The main aim of the thesis is to experimentally investigate radiative heating due to mid-wave infrared (MWIR) radiation in Martian-simulant gas mixtures. As will be discussed, significant uncertainties - with relevance for future missions - exist in this area. The work will confirm previous results, produce new data of interest and, finally, propose improvements to existing modelling tools which will enable prediction of vehicle radiative heating with greater confidence.In support of these aims time has been spent on the development of the new T6 aluminium shock tube (AST). This facility will be the highest enthalpy ground test facility in Europe when complete, providing a unique capability for the study of aerothermodynamic effects. To ensure that the potential of this resource is fully realised a series of modelling exercises have been carried out, confirming the required performance is achievable. Developing a more in-depth understanding of the eventual capabilities of the facility has in turn allowed a more pragmatic review of current literature in the field, with future work being planned to exploit the shock tube's strengths.