摘要
利用风洞试验的方法对某型直升机的防砂滤试件在低温环境下的结冰情况进行了研究。试验过程中,运行0. 3m×0. 2m结冰风洞制冷系统降低风洞内部气流温度,通过优选风洞喷雾系统的两相流喷嘴位置,合理设置喷嘴入口的水压与气压来满足不同试验段风速下的液态水含量及水滴直径要求。结果表明,防砂滤试件在低风速下会发生结冰现象,使得试件进出口压力损失增大,影响试件性能,而在高风速环境中结冰情况则明显改善。另外,试验同时发现防砂滤试件的结冰起始于试件的中部偏下游的位置,而后再逐渐向上游蔓延。文中应用势流分析方法对这一现象进行了分析。
In this paper,the icing condition of a certain type of helicopter's sand filter specimen under low temperature environment was studied by wind tunnel experiment. During the test,the refrigeration system of the 0. 3 m* 0. 2 m icing tunnel was used to reduce the air temperature inside the wind tunnel. By optimizing the position of the two-phase flow nozzle in the wind tunnel spray system and reasonably setting the water pressure and air pressure at the inlet of the nozzle,the requirement of liquid water content and diameter of the water droplets was satisfied under different test section wind velocities. The results show that the icing of the sand filter specimen is mainly affected by the ambient temperature,the incoming water content,and the inflow wind speed. In addition,the experiment also found that the icing of the sand filter specimen started at the downstream part of the specimen,and then gradually spread to the upstream. This paper analyzes this phenomenon using the potential flow analysis method.
引文
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