Abstract:
The asphalt pavement repair has the requirements of fast reaching the site, timely repair, and opening to traffic soon.In order to meet the requirements, the heating efficiency of asphalt pavement maintenance vehicle is very important.The existing heating asphalt mixture has low heating efficiency and can’t meet the increasing need of asphalt pavement repair.In order to solve the problems of lower heating efficiency, excessive radiation and other defects of the domestic asphalt pavement maintenance vehicle, and to improve the heating quality and heating efficiency of asphalt mixture in asphalt pavement maintenance, a new type of heating and stirring roller of asphalt pavement maintenance vehicle is proposed.The Fluent software is used to simulate the heating efficiency of the heating roller, which provides the theoretical basis and research methods for the design of the heating drum of asphalt mixture and the temperature field analysis.The asphalt mixture heating roller with stirring function is designed, the roller structure and thermal insulation layer are calculated, and the design calculation method is given.By using the Fluent simulation software, the heating process of asphalt mixture is simulated by using standard k-ε double-equation model and heat transfer model.Through numerical simulation and analysis, the three-dimensional (3D) analysis model of asphalt mixture flow and heat is established.Meantime, the simulation analysis and experimental verification are carried out.The results show that the asphalt mixture has high heating efficiency and good heating uniformity using the designed stirring and heating roller.In the heating process, the bottom temperature is always higher than that of the intermediate layer and the surface layer.At the end of the heating, temperature difference between the surface and the bottom is about 1 ℃, asphalt mixture has a uniform distribution of temperature which has reached 160 ℃, and heating effect is good without temperature segregation.Compared with the traditional heat conduction oil heating method, the heating time can be shortened from 8 h to 35 min, and the heating efficiency of the heating roller is greatly increased.In order to further analyze the influence of the structure of the heating roller on the heating efficiency, the rotating speed of the roller is set to 5 r/min, and the influence of the height of the blade and the spiral angle on the heating efficiency is analyzed.Through the analysis of the coupling simulation of roller blade parameters, it is found that when the rise angle of the helical blade is 68° and the blade height is 300 mm, the mixed material heating efficiency is the highest.Finally, in order to verify the simulation results of the heating drum structure design and heating efficiency, the specific test is carried out.The initial temperature of asphalt mixture is 25 ℃, the quality is 2000 kg, and the time heating to the mixture temperature of 160 ℃ needs 35 min.From the experimental results, the actual heating time is 35 min and the simulation result is 32 min, which shows that the simulation result is consistent with the actual one.The study can provide theoretical basis for the design of asphalt pavement maintenance vehicle heating device.