摘要
针对高速飞行器长航时会面临非烧蚀型大面积热防护的问题,以SiC气凝胶作为隔热层的轻质防隔热一体化结构,考虑隔热材料热导率的温度相关性,建立瞬态传热模型。采用有限差分法中的Crank-Nicolson方法,计算并讨论了不同条件下结构的隔热性能,并与隔热层为陶瓷纤维隔热毡的结构进行对比,分析了SiC气凝胶在结构中的隔热特性及优势。进而对SiC气凝胶的厚度尺寸进行优化,求解在满足约束条件下SiC气凝胶的最小厚度。结果表明使用SiC气凝胶的热防护结构,在相同结构厚度下隔热能力提升约40%,在隔热效果相同时厚度降低约65%。通过与有限元分析软件的对比,证明了厚度优化设计的数值解法的准确性。
Focusing on the thermal protection problem of a long-endurance hypersonic vehicle with non-ablative materials,a lightweight thermal insulation integrated structure using SiC aerogel is investigated.Considering the temperature dependence of thermal conductivity of the insulation material,a one-dimensional transient heat transfer model is established.The thermal insulation performance of the structure under different conditions is calculated and discussed by using the Crank-Nicolson method,which is one of the finite difference method.Compared with the structure using ceramic fiber heat insulation felt,the advantages of SiC aerogel are analyzed and discussed.Finally,optimization on the thickness of SiC aerogel layer is carried out,and the minimum thickness under constraint conditions is calculated.The results show that the thermal insulation capacity of the thermal protection structure using SiC aerogel increases by about 40%under the same structure thickness,and the thickness decreases by about 65%under the same thermal insulation effect.The accuracy of the numerical solution for thickness optimization design has been proven through comparison with finite element analysis software.
作者
杭子轩
戴婷
李珺
HANG Zixuan;DAI Ting;LI Jun(School of Aeronautics and Astronautics,Central South University,Changsha,410083)
基金
湖南省自然科学青年基金(2020JJ5681)。
作者简介
杭子轩(1996-),男,硕士研究生,主要研究方向为飞行器热防护结构设计;戴婷(1990-),女,博士,副教授,主要研究方向为飞行器热防护结构设计、智能材料与结构力学;李珺(1989-),男,博士,副教授,主要研究方向为长航时飞行器总体设计、临近空间浮空型飞行器设计。
