加热距离与风速对协同加热沥青路面的影响

Influence of heating distance and wind speed on coupling heating asphalt pavement

为了提高沥青路面就地热再生时的加热均匀性与效率,提出一种红外辐射与热风循环协同加热方法,建立协同加热沥青路面的物理模型与数学模型.借助计算流体动力学(CFD)仿真软件进行仿真分析,寻找协同加热沥青路面时加热距离与风速对沥青路面加热均匀性与效率的影响规律和最佳加热方案.结果表明:采用协同加热法具有热风循环与红外辐射单独加热不具备的优点,既能避免红外辐射加热时路面表层过热老化,又比热风加热有更高的加热效率,从而获得更高的加热均匀性与效率;有利于路面深层的加热和降低路面表层温度的上升,解决了在就地热再生施工中由于路表起火而导致的路面再生质量下降;加热板加热距离增大和热风风速增加都不利于路面对热能的吸收,风速对沥青路面加热效率的影响会随着加热距离的增加而减弱;加热距离对加热效率起主导作用,加热均匀性与效率同风速与加热板的距离匹配密切相关.

To improve the heating homogenization and efficiency of asphalt pavement in hot in-place recycling,a coupling heating method was proposed considering the characteristics of infrared radiation heating and hot air cycle heating,and the physical and mathematical model of asphalt pavement by coupling heating method were established.The computational fluid dynamics(CFD) simulation software was used to analyze the influence of heating distance and wind speed on the heating homogenization and efficiency of asphalt pavement and find the best heating scheme.Results show that the coupling heating method has the advantages that single heating method cannot have,whether it is heated by hot air circulation or by infrared radiation alone.The coupling heating method can not only avoid the overheating and aging of pavement surface when heated by infrared radiation,but also have higher heating efficiency than that when heated by hot air,so it can obtain higher heating homogenization and efficiency.Moreover,it is not only conducive to the deep heating of the road surface,but also helps to reduce the rise of the surface temperature of the road surface,which solves the problem of the decline of the quality of the road regeneration caused by the fire on the road surface during the construction of the geothermal regeneration.The increase of heating distance of heating plate and the increase of wind speed of hot air are not conducive to the absorption of heat energy on the road surface,and the influence of wind speed on heating efficiency of asphalt pavement will decrease with the increase of heating distance.The heating distance plays a leading role in heating efficiency,while the final heating homogenization and efficiency of asphalt pavement is closely related to the matching of wind speed and heating distance.