多物理场下微波加热沥青混凝土传热性能研究  

Heat transfer mechanism of microwave heating asphalt concrete based on multi-physical field

作　　者：刘小明[1] 赵昱 魏子奇 颜大雄 LIU Xiaoming;ZHAO Yu;WEI Ziqi;YAN Daxiong(School of Civil Engineering,Central South University,Changsha 410083,China)

机构地区：[1]中南大学土木工程学院,湖南长沙410083

出　　处：《中南大学学报（自然科学版）》2021年第7期2321-2331,共11页Journal of Central South University:Science and Technology

基　　金：国家自然科学基金资助项目(52078499)。

摘　　要：传统沥青混凝土导热性能差,会产生微波加热温度均匀性差与作用深度小的问题。为了探究影响传热性能的因素,采用数值仿真模拟的方法,根据麦克斯韦方程与傅里叶方程建立传热模型,分析微波加热下,电磁场、材料介电常数以及导热结构对沥青混凝土传热性能的影响。研究结果表明:在这3个影响因素中,电磁场是影响微波加热下模型温升速率以及传热性能的外部因素,电磁场强度越大,模型微波加热温度越高,作用面积越大,模型温度均匀性越好,双波导结构模型比单波导结构模型的温度协同常数(TCOV)降低约16%;较高的介电常数虽然会提高微波加热速率,但温度均匀性变差;导热结构的加入可以明显改善模型的传热性能,当导热结构布置在靠近微波发射源的位置时,相对于其他布置方式,模型的温度均匀性最佳,相较于普通沥青混凝土模型,TCOV可提高17.5%;当外部电磁场一定时,可通过改变沥青混凝土的介电常数并在内部形成高导热结构来提高其传热性能。The poor thermal conductivity of traditional asphalt concrete will lead to the problems of poor temperature uniformity and small depth of microwave heating.In order to explore the factors that affect the heat transfer performance,a heat transfer model was established based on Maxwell equation and Fourier equation by numerical simulation method.The effects of electromagnetic field,material dielectric constant and heat conduction structure on the heat transfer performance of asphalt concrete during microwave heating were analyzed.The results show that the electromagnetic field is the external factor affecting the temperature increasing rate and heat transfer performance of the model during microwave heating.The larger the electromagnetic field intensity,the higher the microwave heating temperature,the more the area,and the better the temperature uniformity of the model.The TCOV(temperature coefficient of varation)of the double waveguide structure model is about 16%lower than that of the single waveguide structure model.For the internal factors,the higher the dielectric constant will increase the microwave heating rate,but the temperature uniformity will become worse.The addition of the heat conduction structure can significantly improve the heat transfer performance of the model.When the heat conduction structure is located near the microwave emission source,the temperature uniformity of the model is the best compared with that of other layout methods,and the TCOV of the model can be increased by 17.5%compared with the ordinary asphalt concrete model.In conclusion,in the case of a certain external electromagnetic field,the heat transfer performance of asphalt concrete can be improved by changing its dielectric constant and constructing a high heat conduction structure inside.

关 键 词：微波加热 沥青混凝土 多物理场 数值模拟 传热性能 温度均匀性 

分 类 号：TU418[建筑科学—岩土工程]