Research On Thermal Insulating Mechanism And Thermal Insulating Efficiency Of Thermal Insulations Of Metallic Thermal Protection System

Metallic thermal protection system (MTPS) is one of the key technologies for developing reusable launch vehicle (RLV).Insulating materials are main insulating element of MTPS. At the present time there are two kinds of insulating materials which can be applied to MTPS and they are respectively ceramic fibrous thermal insulations (CFTI)(optical thickness more than 10) and multi-layer thermal insulations (MTI). The dissertation adopted a kind of method which combined theory with experiment to analyze heat transfer mechanism during reentry of RLV and according to these mechanism one-dimension steady and transient heat transfer model, three-dimension transient heat transfer model of alumina silicate ceramic fibrous insulating materials and one-dimension heat transfer model of MTI are established. Experiments which are made for alumina silicate CFTI is hpopheful to be applied to the next generation RLV validated these models. Thermal insulating efficiency is one key guideline to choose insulating materials of TPS. According to the thermal insulating efficiency, methods which combined theory with experiment are adopted to investigate and compare thermal insulating efficiency of CFTI with the same density and composite CFTI and it is found that thermal insulating efficiency of composite CFTI is better than that of CFTI with the same density. One-dimension heat transfer modle of MTI is established and thermal insulating efficiency of MTI is investigated.The content of this dissertation include five parts which are respectively presented as follows:One-dimension heat conductive transfer model of CFTI is established and One-dimension thermal radiation transfer model is also established by means of Rosseland approximate method. By means of above two model and energy balanced equation, One-dimension heat transfer model of CFTI is established. Experiments for measuring effective thermal conductivity of alumina silicate CFTI with three kind densities are made at the temperature from 100℃to 800℃. By means of genetic algorithm and experiment data, density radiative attenuation coefficient and heat conductive adjusting coefficient of alumina silicate CFTI are obtained.