基于多源多腔阵列式微波加热的沥青混合料多物理场耦合基础理论研究

Adopting microwave heating to realize asphalt mixtures recycling can make internal and external material hot simultaneously and has the virtues of rapid heating, deep penetration, wide heating range, et al. Mass and heat exchange theory, electromagnetic transmission theory and dielectric measurement technology are adopted to deeply research the basic theory of multi-field coupling for asphalt mixtures based on multi-source and multi-cavity aligned array microwave heating. The main research contents include the following. Mutual coupling model of electromagnetic fields and coupling model of directivity in near field radiation are built based on port network of transmission line with multi-source and multi-cavity heating system. The models are verified by measure of antenna gain. Dielectric properties of asphalt mixtures are tested through free-space method. Thermal-thermal coupling model is set up and explicit-implicit integral algorithm is put forward. Control methods of heat flow behavior and optimization principle of coupling behavior are set up. Coupling models of mass, heat and electric are built under the condition of multi-field. The influence of dielectric parameters, structure parameters and array parameters on the coupling models is established. Parameters of cavities and array structures are optimized under conditions of complex fields. A set of basic theories will be built for microwave heating technique, which will offer scientific basis for improvement of recycling quality，energy saving and development of maintenance machinery.

采用微波加热实现沥青混合料再生可达到混合料内外部同时受热的效果，具有加热速度快、穿透能力强、加热范围广等优点。在基于单工作腔微波加热研究基础上，本课题采用质热交换理论、电磁传输理论和介电测试技术对基于多源多腔阵列式微波加热的沥青混合料多物理场耦合问题进行深入研究，研究内容包括：基于多源多腔加热系统的传输线端口网络建立近场辐射下的电磁场互耦模型及方向性系数耦合模型，利用天线增益的测定完成模型的验证；采用自由空间法进行沥青混合料介电特性测试，构建热场-热场的互耦合模型并提出模型的显隐式积分算法，建立热流流动行为的控制方法及耦合行为的优化原理；建立多物理场共存条件下沥青混合料质热电耦合模型，确立介电参数、结构参数及阵列参数对耦合模型的影响规律，完成复杂外场条件下的工作腔和阵列结构参数优化。本课题将在微波加热技术领域建立一套基础理论，为提高沥青混合料再生质量、节约能源及开发热再生装备提供科学依据。

本项目以提高沥青路面微波热再生质量并节约能源为目的，对多源多腔阵列式微波加热过程沥青混合料多物理场耦合理论进行了研究，在天线电磁辐射场互耦、沥青混合料热场互耦和质热电耦合方面取得了一定的成果。分析了天线结构参数与方向性的关系，发现了天线的高度和口面长宽比对辐射电磁场增益分布均匀性的影响，进行了天线结构优化。研究了微波加热热场控制理论，分析了天线结构、加热方式、微波功率、沥青路面结构、沥青路面湿度对温度场的影响规律。设计了阵列式微波加热沥青混合料实验装置，可实现多加热腔间的距离和辐射高度调节，研究加热系统中微波热再生介电损耗模型及定解条件，采用泛函方法进行了数值解析。分析了天线辐射加热的热场和电场的分布特点，研究了阵列天线加热时电磁场的互耦原理，发现了天线耦合条件下电磁场和热场的分布规律，分析了天线间距对电磁场互耦与热场互耦的影响，发现保持一定的天线间距可以改善场分布的均匀性。进行了传热传质实验装置设计，建立热湿并存的耦合模型，发现影响质热耦合的关键参数，进行了质热耦合模型的数值模拟。建立了普适性的多物理场共存的耦合模型，实现多物理参数的联系，发现初始含水率对温度上升和湿分迁移速率的作用规律，完成了阵列式加热系统方案的优化。