基于温度和速度均匀性的侧送风烘房设计及仿真

Design and simulation of side air supply drying room based on temperature and velocity homogeneity

为提高农业机械零部件烘房温度均匀性,该研究设计并优化送风参数,分析其对速度场、温度场的影响。首先,通过理论分析和计算流体力学(Computational Fluid Dynamics)相结合的方法,对所设计的农机零部件烘房速度场、温度场进行数值模拟,得到烘房内速度、温度分布规律。进一步分析各送风参数对速度均匀性、温度均匀性的影响。结果表明:单侧送风回风方式优于双侧送风回风;送风口数量为8时,温度、速度均匀性较好;送风角度15°时,速度、温度均匀性较好。试验数值和模拟数值误差较小,温度误差小于1.68%,风速误差小于1.1 m/s,仿真结果可靠有效。所设计的农机零部件烘房工作稳定可靠,温度不均匀系数低于6%,满足设计要求。该研究可为农机零部件烘房结构设计及参数选取提供理论依据。

Coating has widely been a commonly-used way to prevent corrosion failure of machinery parts. Coating of agricultural machinery parts is also conducive to improving the working reliability and service life of machinery. Drying is thus the key link of parts coating. However, improper drying can cause the reduction of film stress, film cracks, shrinkage, and pinholes. In this study, a side air supply drying room was designed suitable for the drying of agricultural machinery parts. The circulation of hot air was used to exchange the heat with the workpiece, further to reduce the moisture content of the coating,and finally to realize the curing of the coating. Computational fluid dynamics software was selected to numerically simulate the velocity and temperature field of the drying room for agricultural machinery parts. The working parameters of the drying room were also optimized to clarify the influence on the velocity and temperature field. As such, the working performance of the drying room was improved to clarify the influence of air supply mode, the number of air supply outlets, and air supply angle on velocity and temperature distribution. The results show that the unilateral air supply performed better than that of the double, indicating better gas circulation in the drying room. The uniformity of speed and temperature was better, particularly with the higher speed of return air and excellent gas circulation, when the number of air inlets was 8 rather than 6 and 10.Furthermore, the uniformity of speed and temperature was better, when the air inlet angle was 15° rather than 0° and 30°,where the return airspeed and temperature were higher. Therefore, an optimal parameter combination of drying room was achieved, where the unilateral side air supply, 8 air supply outlets, and air supply angle of 15°, indicating excellent gas circulation, as well as the better uniformity of speed and temperature. The measured values of each index were in good agreement with the theoretical optimization, where the temperature error was less than 1.68%, and the wind speed error was less than 33%, indicating reliable and effective simulation. At the same time, the overall coefficient of temperature inhomogeneity was less than 6%, where the designed drying room worked stably and reliably for agricultural machinery parts,fully meeting the design requirements. This finding can provide a strong reference for the design of the subsequent drying rooms.