沥青路面微波现场热再生热电场模型

为了提高微波加热沥青混合料内辐射电场的效率及温度场分布的均匀性, 应用惠更斯原理对基本面元辐射场积分建立了微波加热装置的辐射电场数学模型, 运用能量守恒原理确定了辐射口面处沥青混合料的温度场数学模型, 分析了结构参数及介质物性对热电场的影响。根据天线近场辐射理论对天线E面及H面长度进行了优化设计, 应用不同长度的两种天线进行微波加热试验, 测出了各自口面温度场分布并进行了计算机模拟。结果发现: 用符合长度准则的天线加热后沥青混合料大部分区域温度为75℃~90℃, 仅在口面周边位置温度略有下降, 而用另一种天线加热后局部区域达到130℃以上, 而大部分区域温度则在70℃以下。可见使用前一种天线加热后温度分布更均匀, 具有更高的加热效率, 从而验证了热电场模型的正确性和结构优化的有效性。

Thermoelectric field model of microwave hot in-place recycling for asphalt pavements

In order to improve the efficiency of radiation electric field and the distribution uniformity of temperature field in microwave heating for asphalt mixtures, the radiation field integrals of basic surface elements were computed, a mathematic model of radiation electric field for microwave heating device was built by using Huygens' principle, a mathematic model of temperature field for asphalt mixtures in front of radiation surface was established by using the law of energy conservation, and the influences of structure parameters and media physical properties on thermoelectric field were analyzed. The lengths of antennas in E-plane and H-plane were optimized by using the theories of antenna near-field radiation, microwave heating experiments were made for two kinds of antennas with different lengths in E-plane and H-plane, and the temperature fields were simulated. Simulation result indicates that the temperatures of asphalt mixtures in most regions are from 75 ℃ to 90 ℃ and decline slightly around the periphery when using the antenna in accordance with the length principle; however, the temperatures are over 130 ℃ in local regions and under 70 ℃ in most regions when using the other antenna. Obviously, the temperature field is more homogeneously and the heating efficiency is improved by using the former antenna, which demonstrates the accuracy of thermoelectric field model and the availability of structure optimization.