Thermal Performance of Multilayer Insulation : 3rd Report, Effects of Various Parameters on Heat Flux

Abstract

Th effects of various parameters on heat flux between room temperature and liquid nitrogen temperature through multilayer insulation (MLI) are examined using the prediction equations and experimental results. The investigated parameters were : the winding method of multilayer insulation, hot boundary temperature, mesh size of the net, number of layers of net inserted between films, direction of layer installation, film thickness, and use of single-vs. double-aluminized films. To accomplish good thermal performance, laminated winding, larger mesh size, a layer of net inserted between films, thinner film (light weight), and double-aluminized film are needed. The optimum number of layers for different parameters is also discussed. It is found that the optimum number of layers is in the range of 30 to 60 layers in many cases.