Experimental research of perforation rate for multilayer insulation used in cryogenic transfer lines

Abstract

In this paper, thermal performance through perforated multilayer insulation (PMLI) is experimentally investigated using a cryogenic transfer line test platform. PMLI consisting of double-Aluminized Mylar and silk netting for 25 layers cm-1 and 50 layers was tested. The experimental results show perforation rate has an optimum value of 0.39% and the corresponding heat flux and effective thermal conductivity reach a minimum value of 2.61 W/m2 and 2.31 ×10-4 W/(m⋅K). In addition, both q and ke increase with rise of absolute pressure in vacuum jacket and the absolute pressure should be maintained lower than 0.01 Pa at least. The research of optimal perforation of PMLI in this study offers reliable experimental basis for manufacturing perforated multilayer insulation cryogenic transfer lines.