Experimental and theoretical study on the optimal placement of reflective shield in multilayer insulation systems.

Multilayer insulation (MLI) systems are widely used in cryogenic applications to minimize heat leak. Despite advancements in research work regarding the optimization of different MLI configurations, there is still a lack of appropriate structural design. The reflective shield will improve the performance of MLI by reducing thermal radiation. This study aims to improve the thermal performance of MLI systems by incorporating reflective shields with MLI materials. More specific, it is focused on determining the optimal placement of reflective shields within the MLI structure to achieve a minimum heat leak. A modified layer-by-layer model has been established to predict the thermal performance obtained from using single and double reflective shield placements. Such predictions were validated through experiments using a liquid nitrogen boil-off calorimeter. The obtained results demonstrate that placing a single reflective shield at the warm boundary improves thermal performance by 18 % compared to using MLI solely, emphasizing the relevance of reflective shield-MLI combinations in cryogenic applications. This work is conducive to offering potential applications for cryogenic clean fuel storage and transportation.