以最佳温度均匀度为目标的常压热循环系统结构参数优化

用数值模拟的方法对常压热循环系统试验箱内试件模型的降温过程进行了研究。研究了不同结构参数下试验箱内试件模型的降温速率及温度均匀度变化规律。结果表明,当模型位于试验箱中心位置时,由于试件模型的阻碍,在其上底面出现滞止区,而在底部产生高温回流区域。试件模型降温速率随离地高度的增加而逐渐加快,最终可在7 h内完成降温过程,最大温度标准差降低至最初的25%。改变试件模型形状,可改变底部回流区域大小,进而加快降温过程的进行。相对于竖直方向上的流体出入方式,流体从侧面出入更有利于降温过程的进行,可明显提高降温速率,改善温度均匀度,将最大温度标准差降低到流体竖直送入方式下的40%。

Structural Parameters Optimization of Thermal Cycle System Based on Temperature Uniformity

The cooling rate and temperature uniformity of the model in the test chamber of the thermal cycle system are investigated numerically under different structural parameters.Results show that when the model is located at the center of the test chamber,due to the obstruction of the model,a stagnation zone appears on the surface of the model,and a high temperature recirculation zone is generated at the bottom of the model.The cooling rate of the model is gradually increased with the increase of the distance between the model and the ground,and the cooling process can be completed within 7 h,In contrast with D=1.0 m,the maximum temperature standard deviation is reduced to 25%,when D=5.0 m.By changing the shape of the model,the size of the recirculation area can be reduced,thereby accelerating the cooling process.Compared with the air supply method in the vertical direction,the lateral ventilation is more conducive to the cooling process.The lateral ventilation can significantly increase the cooling rate,and can significantly improve the temperature uniformity,and reduce the maximum temperature standard deviation to 40%of the vertical air supply method.