Abstract
Multilayer flow insulation is proposed to improve the performance of single layer flow insulation. Dividing a single porous layer, open-cellular porous materials, into multiple porous layers is always effective to obtain a large gas temperature drop ΔT_f across a flow insulation system. The energy equation of the gas and of the solid phases is employed by using separate energy equations model, and the convective heat transfer between the two phases based on an empirical volumetric heat transfer coefficient proposed by Kamiuto and San San Yee is estimated. The P_1 approximation is used to evaluate the radiation of transfer equation. When an equivalent blackbody radiation temperature of the radiation coming from the upstream region exceeds an inlet gas temperature, use of a high reflective porous plate on the upstream side and a low reflective porous plate on the downstream side is quite effective to increase ΔT_f.
