Axiomatic design of a reflective multilayer high-temperature insulator

High-temperature insulators protect structures against extreme thermal loads in various industries such as energy and space-related areas. For such insulations, radiation is the dominant mode of heat transfer. The intended multilayer high-temperature insulator utilizes reflection as the controlling mechanism for the radiative heat transfer. In the current study, the axiomatic design methodology is used to map the design process of a reflective multilayer high-temperature insulator. In addition, an analytical model is developed to simulate the combined radiation and conduction heat transfer in the reflective multilayer high-temperature insulator. The model was solved numerically and validated with the existing experimental results. The obtained results depict that design process of the multilayer high-temperature insulator would be decouple if two reflection surfaces are used for the insulator. Also, the reflective surfaces control the transmission of the radiation in two ways: they control thermal emittance to the insulator's cold side and control conversion of radiation to conduction, as well. Radiation emittance and conversion will be minimized where the reflective surface is located near the cold and hot side of the insulator, respectively. This issue justifies different results in the literature about most effective location of the inserted reflective layers.