单喷嘴喷雾冷却旋转圆筒的换热特性实验研究

采用单喷嘴喷雾冷却的换热方式来研究旋转圆筒的换热特性。通过设置不同的参数,观察圆筒外壁的温度分布及变化规律,并计算物料的热流密度。实验结果表明,物料到筒外壁之间的热阻会对换热过程产生严重的制约;未喷雾时,外壁面温度达到物料的30%,而喷雾时,达到11%。随着物料温度的升高,外壁平均温度会显著升高,物料的热流密度增长幅度也会逐渐的增大;并且温度越高,喷雾冷却的优势越明显。圆筒转速对温度的分布会产生一定的影响,转速越高,温度分布越均匀,热流密度也会有所提升;当提升1 r/min时,热流密度提高不到1%;喷雾流量对换热效果的影响较大,热流密度随流量的增大而增大,但增长速率会逐渐减缓。

Experimental investigation of heat transfer from rotating cylinder by single-nozzle spraying

The heat transfer characteristics are investigated for rotating cylinder by single-nozzle spray cooling method. The surface temperatures of the cylinder are measured under different cooling parameters and the heat fluxes of the material are calculated. The results show that, heat resistant between material and outside surface has a great influent on the heat transferring of the whole system. And with the increase of material temperature, the cylinder surface temperature is rising and the heat flux significantly will grow too. Under higher temperature of outside surface, spray cooling method has a significant advantage than no spraying. Rotation speed has a certain impact on the temperature distribution, the higher the speed is, the more uniform the temperature is, and the heat flux will go up 1% when the spread rises up 1r/min. Spray mass flux has a great impact on heat transfer. Increasing mass flux will increase heat flux, but the growth rate will be slowing.