大型连续式跨声速风洞干燥系统参数优化研究

Study on the parameter optimization of air-drying system in large continuous transonic wind tunnel

在跨声速风洞中,试验段水汽凝结会使气流变为非等熵流动并产生凝结波,严重破坏流场均匀性并对测试数据产生影响。因此,试验前需对气流进行干燥使其含湿量低于1.5 g/kg。大型连续式跨声速风洞经济、高效的气流干燥途径是设置循环干燥系统。针对连续式跨声速风洞干燥要求及运行特点,确定了转轮联合冷却除湿的总体技术方案,提出了基于均匀掺混假设的洞内气流干燥仿真计算模型,对系统总体参数进行了设计和优化。研究发现:当循环次数在2次以上时,模型可有效评估洞内气流平均含湿量变化情况,与试验偏差在8.3%以内;充分利用具有较高除湿能力的前4次循环和所选配转轮的除湿能力,可将前、后表冷器最大冷却负荷分别降低约41.9%和27.8%,提高设备使用效率。

In the transonic wind tunnel, the flow of wet air can turn into non-isentropic flow due to water vapor condensation in the test section, followed by the formation of condensation wave, seriously destroying the uniformity of the flow field and the accuracy of the test data.Therefore, the air should be dried ahead of test to ensure its moisture content less than 1.5 g/kg.The circulation drying system is an economical and efficient air-drying way in the large continuous transonic wind tunnel. In this paper, a rotary and cooling dehumidification drying system is designed for the wind tunnel, and an air-drying calculation model based on the assumption of uniform mixing is proposed and validated by experiment. According to the proposed model,the optimized parameters of the air-drying system are obtained. The results show that the model can effectively estimate the change of the average moisture content in the tunnel,and the deviation from the test is within 8.3% when the number of cycles is more than 2;the maximum cooling load of the front and rear heat exchanger can be reduced by about 41.9% and27.8% respectively in this system by making full use of the dehumidification capacity of the first four cycles and the selected rotary dehumidifier.