Research Of Heat Transfer In Multilayer Insulation For Space Vehicles

The space vehicle must undergo the extremely bad environment during the work process. In order to guarantee flight crew safety and make sure the inner apparatus normal work, it is necessary to establish insulation equipment to reduce the space vehicle interior temperature difference as much as possible. After several decade research, the thermal protection system's develop have made rapid progress. Among the multitudinous thermal protection system plans, the metal thermal protection system was considered to be the first choice. In this dissertation, multilayer insulation system belongs to the metal thermal protection system.During the space vehicle moving in an orbit, the purpose of this dissertation is to mainly research the steady heat transfer in multilayer insulation system. Rarefied gas conduction and microscale radiation are considered as the main heat transfer way. It is a new idea to research microscale radiation in multilayer insulation system. The thermal analysis model is to be established using the finite difference method and the node analysis method. The former is that the energy equilibrium equation is domain discretized to set up the difference equation, and the latter is to establish the equations with the relation that heat-flux at each node is equivalent at steady state. Through calculating the example, the precision of the node analysis is higher than the finite difference method's.In the multilayer insulation system design, the various parameters design is the most important. Numerical simulation is made for the objects with different parameters by the node analysis thermal model. Analyzing the layer density from two aspects, the layer density is increased when total thickness is invariable, and the layer density is increased when the total layer is invariable The calculation results are analyzed and the effects of parameters such as layer density, numbers of layer and vacuum degree are clarified. The results are helpful to the optimum design of the multilayer insulation system.