微纳孔隙材料光热信息高温耦合传递的时频特性研究

Micro/nano porous materials have a large potential in many technologies, such as thermal protection system at high temperature, transpiration cooling, fuel cell, and so on. High-temperature optical-thermal properties are essential to the structural design and performance evaluation. This project focuses on the measurement of optical-thermal properties, to investigate the time-frequency characteristics through the coupled radiative and conductive heat transfer in the materials subjected to a periodic irradiation.. The main contents include: coupled mechanism and time-frequency characteristics of the optical-thermal transfer under a periodic irradiation, experimental method of optical-thermal response and time-frequency characteristic numbers accessing, optical-thermal properties identification combining multi-information of the time-frequency domain.. Based on research, master the analytical methods of time-frequency characteristics for the optical-thermal coupled transfer within such materials, obtain the experimental data of optical-thermal response characteristics for typical materials, reveal time-frequency domain characteristics of the radiative heat transfer and conductive heat transfer respectively, and establish optical-thermal properties identification method by combining multi-information of the time-frequency domain. This research can provide fundamental support for the innovative measurement method to obtain optical-thermal properties of micro/nano thermal insulations, promote the development of the related disciplines and technologies, including optical-thermal measurement at high-temperature, thermophysical properties, coupled heat transfer and thermal radiation.

微纳孔隙材料在高温热防护、发汗冷却、燃料电池等技术中有重要的应用需求和发展前景。其高温光热物性参数，是材料结构设计及性能评价的基础。本项目针对微纳孔隙材料高温光热物性参数实验测量难题，以周期性辐射源照射下材料内辐射-导热高温耦合过程为对象，研究其光热信息传递的时频特性。. 研究内容包括：周期性辐射源作用下材料对光热信息耦合传递的过程机制与时频特性分析、获取材料光热时频特征参数瞬态响应的实验研究、基于多信息时频特征融合的微纳孔隙材料光热物性参数辨识。. 通过研究，掌握此类材料光热信息耦合传递的时频分析方法，获得典型材料的光热响应特性实验数据，揭示高温耦合过程中辐射、导热两种传递方式的时频信息特征，构建基于多信息时频特征融合的高温光热物性参数辨识方法。为微纳孔隙材料高温光热物性参数实验测量方法的技术原理创新提供基础支撑，促进高温光热测量、热物性、耦合传热及热辐射等学科发展。

微纳孔隙材料在高超声速飞行器高温热防护、核能与太阳能高温热利用、燃料电池、多孔燃烧等领域有着重要的应用需求和发展前景。准确获取微纳孔隙材料的高温热物性参数，对其在上述领域的创新应用有重要指导意义。本研究针对高温热物性参数获取技术中有效信息少、杂散干扰强等难题，以材料内辐射-导热高温耦合过程为对象，开展了光热信息传递的时频特性研究。分析了高温条件下微纳孔隙材料内部的辐射-导热耦合传热机制，建立了大温度梯度下微纳孔隙材料的导热系数场、衰减系数场及散射系数场的耦合分析模型。基于已具备的实验装置，辨识微纳孔隙材料温度数据的时空特征。发展了智能-梯度混合算法、黄金正弦算法等反演方法，得到了不同类型微纳孔隙材料的高温光热物性参数。并以某气凝胶材料为例，研究了实验技术与反演方法对测量结果的影响，进行了误差分析。研究成果为我国相关型号的研制提供了基础数据。研究涉及了热辐射理论、实验传热学、光谱学等多学科交叉，是目前国际上热辐射及相关领域的前沿课题。