Heat transfer model and solution of microwave hot recycling for asphalt pavement

In order to achieve the temperature field of microwave hot recycling for asphalt pavement, heat transfer form was analyzed based on heat transfer theory, the corresponding 3D unsteady heat transfer model was built, boundary conditions were studied, convective heat transfer coefficient and radiation heat transfer emissivity were solved, the strength of internal heat source was studied according to energy conservation principle, and transformation between electric field and thermal field was realized, the numerical solution of heat transfer model was researched by adopting alternation direction explicit (ADE) scheme, the mathematic models of heat transfer boundary conditions were established by fitting experimental temperatures, and visualized numerical solution was obtained by simulation.Computation result shows that the temperatures of asphalt mixture in most region approach to 70 ℃ after heating for 450 s, reach about 80 ℃ after heating for 600 s, and reach about 110 ℃ rapidly after heating for 750 s; heat transfer is nonlinear and the heating time must be chosen accurately to guarantee repair quality.