Investigation of Interlayer Thermal Coupling of Multilayer Insulation in Spacecraft Equipment

Abstract

In general, for installing multilayer insulation (MLI) blankets on curved spacecraft equipment, creating a pattern that has multiple sectors is necessary because of the impossibility of establishing a single piece of MLI. The sector area of the MLI contains numerous seams and sewing. Therefore, prediction of overall performance or effective emittance is not simply possible, and they need to be tested in some experimental ways. The aim of the current research is to present a methodology for determining the conductivity between layers in both nonsewing and sewing regions of MLI to correctly estimate the effective emittance coefficient and the thermal behavior of MLI. Firstly, by conducting two experimental tests, both sewn and nonsewn square MLIs’ effective emittance coefficients are computed. In the second step, the conductive thermal coupling coefficients of nonsewing and sewing regions are determined as 1.615 and 1.95 W/(m2⋅K) respectively, utilizing experimental data. In the third step, a spherical geometry fuel tank is selected as a case study, and these coefficients are utilized in the simulation process of an MLI tank. Finally, the overall effective emittance coefficient of that tank is determined. The results indicate that the effective emittance is reduced by about 8%.