【作者】 闫长海；

【导师】 杜善义； 孟松鹤；

【作者基本信息】 哈尔滨工业大学 ， 工程力学， 2006， 博士

【摘要】 金属热防护系统(MTPS)是可重复使用运载器(RLV)的关键技术之一,而隔热材料是金属热防护系统的主要隔热部件。目前应用于金属热防护系统的隔热材料主要有陶瓷纤维隔热毡(CFTI) (光学厚度大于10)和多层隔热材料(MTI)。本文采用理论和实验相结合的方法对这两种隔热材料在再入期间的瞬态传热机理进行了详尽分析并建立了陶瓷纤维隔热毡的一维和三维传热模型以及多层隔热材料的一维传热模型,并对有应用前景的硅酸铝陶瓷纤维隔热毡进行了传热实验。本文提出了隔热效率的概念,以表明在取得相同隔热效果的前提下,隔热材料的隔热效率越高,其重量越轻。本文采用实验和理论分析相结合的方法研究比较均质和复合陶瓷纤维隔热毡的隔热效率,发现经过优化设计的复合陶瓷纤维隔热毡的隔热效率高于均质单一密度的陶瓷纤维隔热毡的隔热效率,并利用多层隔热材料的一维传热模型研究了多层隔热材料的隔热效率。本文的研究内容主要包括五个部分,下面进行分别介绍:建立了陶瓷纤维隔热毡一维热传导的传热模型,并利用Rosseland近似法建立了陶瓷纤维隔热毡热辐射的传热模型。利用能量平衡方程和上述两种传热模型建立了的陶瓷纤维隔热毡的一维稳态传热模型。本文通过实验测量了三种密度硅酸铝陶瓷纤维隔热毡在100℃～800℃之间的表观导热系数。利用遗传算法和三种密度的硅酸铝陶瓷纤维隔热毡表观导热系数的实验测量值得到硅酸铝陶瓷纤维隔热毡的密度辐射衰减系数和热传导调节系数。通过实验发现,在温度确定的条件下,均质陶瓷纤维隔热毡表观导热系数并不总是随着密度的增加逐渐变小,而是有一个最小值。达到最小值后,均质陶瓷纤维隔热毡的表观导热系数反而随着密度的增加而增加,并且随着温度的增加,均质陶瓷纤维隔热毡表观导热系数的最小值对应的密度逐渐增加。与均质陶瓷纤维隔热毡相比,复合陶瓷纤维隔热毡可以提供更高的隔热效率,且温度越高,这种优势越明显。通过计算得到了上表面温度为1000℃,下表面温度为30℃情况下表观导热系数最小的复合硅酸铝陶瓷纤维隔热毡的构成。与同密度的均质硅酸铝陶瓷纤维隔热毡相比,其表观导热系数降低了5.9%,而隔热效率提高了5.9%。在陶瓷纤维隔热毡一维稳态传热模型的基础上建立了陶瓷纤维隔热毡的一维瞬态传热模型。通过计算发现,随着密度的增加,应用在金属热防护系统上的均质陶瓷纤维隔热毡所应采取的厚度是降低的,其隔热效率也更多还原

【Abstract】 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.更多还原