Heat Transfer Simulation And Experiment Of Carbon Areogels Infiltrated RVC

Aerospace vehicles have to suffer the severe aerodynamic heating environment when theycruising in the dense atmosphere or during reentry process. To search a new type of lightweight, high efficient heat insulation material is a pursuit objective of future hypersonicvehicle surface thermal protection technology. In this paper, carbon aerogel was infiltratedinto carbon foam to obtain a carbon product with good thermal insulation, and the thermalproperties of materials were studied by numerical simulation.Firstly, the heat transfer performance of carbon aerogel and carbon foam was analyzed.According to the microstructure and thermal properties of carbon foam and using AutoCADVBA program, foam geometry models were got and their effective thermal conductivitieswere simulated by Fluent software. The results show that the air heat transfer and radiativetransfer has made great contributions for carbon foam heat transfer. Theoretically, it provedthat the heat insulation performance of carbon foam could be further improved afterinfiltration low thermal conductivity and radiation resistance materials. Referring the relativetheories and empirical formulas, the solidus/gaseous/radiation conductivity and gaseous-solidcoupling thermal conductivity of carbon aerogel was calculated.Then, according to the previous analysis, the thermal properties of carbon aerogel/RVCcomposite were studied in this paper. The analysis results showed that the composite heatinsulation was greatly improved and better than single material. It provided theoreticalreferences for thermal insulating applications and experiment preparation of carbonaerogel/RVC composites.Finally, the preparation of carbon aerogel/RVC composites was explored. Carbon aerogelprecursor was infiltrated into carbon foams, after SOL-GEL, ageing, solvent replacement,freeze drying and carbonization, a size-stable carbon aerogel/RVC composites which havegood thermal isolation property was obtained. After infiltration carbon aerogel, the effectivethermal conductivity most dropped22.6%, the thermal isolation was improved.