Inverse Identification of the Residual Gas Pressure Distribution in High Vacuum Multi-layer Insulation

High vacuum is a basic condition for the multilayer insulation at the liquid hydrogen temperature zone, and the residual gas pressure distribution in multilayer insulation materials(MLIs) obtained by different evacuation processes results in the obvious different performance of the insulation structure. In order to predict the residual gas pressure distribution of MLIs and use it as the basis for the evaluation of different evacuating processes, this study is based on the layer-bylayer heat transfer model. A sample set composed of temperature distributions corresponding to different residual gas pressure distributions of MLIs is established by theoretical calculation. The orthogonal basis was obtained by truncated singular value decomposition, and then the orthogonal basis coefficient was predicted by Tikhonov regularization method according to the measured temperature distribution of the MLIs, and the residual gas pressure distribution is reconstructed finally. It is validated by the given examples, and the residual gas pressure distribution can be obtained by the inverse identification method on the basis of the temperature distribution of the MLIs. Moreover, the performance of multilayer insulation materials can be predicted more accurately. This paper can provide a reference for the evaluation, comparison and optimization of the evacuation processes of high-vacuum multilayer insulation structures for liquid hydrogen containers.