Oblique Shock Wave Appeared in the Supersonic Two-phase Flow Nozzle of the Carbon Dioxide Gas
Oblique Shock Wave Appeared in the Supersonic Two-phase Flow Nozzle of the Carbon Dioxide Gas
复制标题
二氧化碳气体超音速两相流喷嘴中出现斜激波
DOI：
10.11368/tse.23.31
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
中川勝文
中科院分区：
文献类型：
--
作者：
川村洋介;中川勝文
提高制冷系统的效率是促进节能的有效措施。我们一直在研究喷射器中的超音速两相流，它可以将二氧化碳制冷循环中消耗的膨胀能转化为有用的压缩能，从而提高循环效率。喷射器的性能受两种流体动力学现象的影响。一个是喷嘴的能量转换效率，另一个是喷射器混合段的压力恢复。后期的压力恢复是由斜激波在混合段产生的。为了提高引射器的效率，有必要阐明两相流中发生的斜激波。本文研究了以二氧化碳气体为工质的超音速两相流喷管中出现的斜激波的特性。对这些激波进行了实验和分析研究。在实验中，我们测量了喷管扩张段斜壁处斜激波的压力分布。由于斜激波上游的减压压力分布服从等熵理论，因此喷管内的两相流处于平衡状态和超声速状态。然而，在斜激波之前和之后的流场处测量压力增加。假设两相流中液滴直径为8 μm的分析可以预测斜激波的实验结果。通过激波角的实验结果与理论分析结果的比较，得出了斜壁面处出现的激波是斜激波的强分支。
It is very effective measures in promoting the saving energy to improve the efficiency of the refrigeration systems. We have been studying on the supersonic two-phase flow in the ejector, which can improve the efficiency of the carbon dioxide refrigeration cycle by converting the exhausted expansion energy into the useful compression energy. The performance of the ejector is affected by two fluid dynamical phenomena. One is the energy conversion efficiency of the nozzle and the other is the pressure recovery in the mixing section in the ejector. The later pressure recovery is performed by oblique shock waves to occur in the mixing section. In order to improve the efficiency of the ejector, it will be essential to elucidate oblique shock waves to occur in the two-phase flow. This paper deals with the characteristic of the oblique shock waves appeared in the supersonic two-phase flow nozzle by using the carbon dioxide gas refrigerant as the working fluid. The experimental and the analytical studies on these shock waves are carried out. In the experiment, we measured the pressure distributions of the oblique shock waves occurring at the inclined wall in divergent section of the nozzle. As the decompression pressure profiles upstream the oblique shock wave obey the isentropic theory, it is definite that the two-phase flow in the nozzle is in the equilibrium state and the supersonic condition. However, the pressure increases are measured at the flow field before and after the oblique shock waves. The analyses which assume the diameter of the droplets in the two-phase flow are 8 μm can predict the experimental results of the oblique shock waves. By comparing the experimental result of the shock wave angel with the analytical one, we conclude that the shock wave appeared at the inclined wall is in the strong branch of the oblique shock wave.