气凝胶复合材料中遮光剂及纤维的掺杂方法

发布时间：2018-03-16 23:07

本文选题：气凝胶　切入点：遮光剂　出处：《科学通报》2017年21期 　论文类型：期刊论文

【摘要】：二氧化硅气凝胶广泛用于各种航天器、飞行器的热防护中,添加遮光剂或纤维能大大改善其在高温下的隔热性能.本文通过计算辐射特性得到遮光剂和纤维不同温度下的最佳掺杂粒径,在复合材料等效热导率最小时得到最佳掺杂量,并应用优化结果设计了具有温度梯度的多层掺杂方案.研究发现:遮光颗粒和纤维的最佳掺杂直径随温度增加而减小,掺杂量随温度增加而增加,研究的4种遮光剂(碳黑、SiC、ZrO_2和TiO_2)中,碳黑具有最好遮光效果,但高温下会被氧化,SiC在高温下具有较好的遮光效果;石英纤维多层掺杂具有最小有效热导率,碳黑与SiC遮光剂和石英纤维共同掺杂对辐射传热的抑制最强.气凝胶复合材料背温实验结果有效证实了掺杂优化方法的正确性.
[Abstract]:Silica aerogels are widely used in thermal protection of spacecraft and aircraft. In this paper, the optimum doping particle size of the shading agent and fiber at different temperatures is obtained by calculating the radiation characteristics, and the optimum doping amount is obtained when the equivalent thermal conductivity of the composite is minimum. Using the optimized results, a multi-layer doping scheme with temperature gradient is designed. It is found that the optimum doping diameter of shaded particles and fibers decreases with the increase of temperature, and the doping amount increases with the increase of temperature. Among the four kinds of sunscreen agents studied (sic _ C _ C _ 2O _ 2 and Tio _ 2s _ 2), carbon black has the best shading effect, but the oxidized sic has better shading effect at high temperature, and the multilayer doping of quartz fiber has the minimum effective thermal conductivity. Carbon black, SiC shading agent and quartz fiber have the strongest inhibition on radiation heat transfer, and the experimental results of back temperature of aerogel composites effectively confirm the correctness of doping optimization method.
【作者单位】：西安交通大学能源与动力工程学院热流科学与工程教育部重点实验室;西安热工研究院有限公司;
【基金】：高等学校博士学科点专项科研基金(20130201110042) 国家自然科学基金(51222604)资助
【分类号】：TB33;TQ427.26

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