Study on the Thermal Insulation Performance of Variable Metal Coating Multilayer Insulation Materials

Abstract

Multi-layer insulation (MLI), recognized for its superior thermal performance, is commonly known as 'super insulation'. Traditional MLI designing utilizes one single metallic coating as the reflective layer, neglecting the impact of temperature variations on metal emissivity. This paper proposes a novel approach, variable metal-coating multilayer insulation (VM-MLI), employing aluminum, gold, and copper as reflective layer materials. By adopting an enhanced layer-by-layer model, theoretical analysis of VM-MLI is conducted within the temperature range of 20-300K, comparing its thermal insulation performance to that of conventional MLI under the same conditions. Additionally, this study examines the influence of layer density, area ratio , pressure, and hot boundary temperature on VM-MLI's heat leakage. The results reveal significant reduction in total heat leakage with VM-MLI. Under the conditions investigated, VM-MLI demonstrates approximately 35% better thermal insulation performance than that of the conventional MLI.

Keywords: Thermal insulation, Multi-layer insulation, cryogenics storage