沥青路面现场微波加热再生模型与实验

为了求解微波加热再生沥青混合料内的温度分布,研究了由于沥青混合料介电常数和比热容是温变参数,从而导致电磁场分布和吸收微波功率的非线性变化.建立了电磁场控制方程和热传递方程耦合的二维非线性热电耦合模型,提出了按微波周期为时间步长交替迭代求解该非线性模型的求解方法.使用了工作频率为2.45 GHz的微波系统,通过连续或间歇辐射加热方式,对不同体积的沥青混合料进行了加热实验.实验结果证实了微波加热再生通过辐射热传递能实现瞬间体积加热,具有快速、加热均匀、保证质量和无污染等特点.

Modeling and experiment of microwave heating for hot in-place recycling of asphalt pavements

For the purpose of ascertaining the temperature distribution in recycling asphalt mixtures, the nonlinear processes of microwave heating was studied taking dielectric permittivity and specific heat of asphalt mixtures as temperature-dependent parameters, which resulted in a nonlinear variation of electromagnetism field distribution and microwave power absorption. A nonlinear two-dimensional thermo-electromagnetic coupling model for the electromagnetic and the heat transfer processes equations is proposed, and a solution approach based on an alternate iteration with a time-step of microwave cycle is suggested. By continuous or interanittent radiation heating experiment with a microwave power system in 2.45 GHz, it is shown that instantaneous volume heating can be achieved by microwave heating through radiation heat transfer. The microwave heating is characterized by its rate, uniformity and non-pollution in hot in-place recycling.