圆形和矩形燃气射流在受限液体中扩展特性的对比研究

发布时间：2018-01-30 05:45

本文关键词： 水下燃气射流扩展特性湍流掺混气液相互作用　出处：《推进技术》2016年09期 　论文类型：期刊论文

【摘要】：为研究不同喷孔结构的燃气射流在受限液体工质空间的扩展特性,采用VOF(Volume of fluids)模型分别对圆柱形充液室中圆形射流和矩形射流扩展过程进行气水耦合数值求解。考虑了燃气可压缩性、流体粘性和热量交换因素对射流扩展特性的影响。通过数值模拟,获得圆形射流扩展形态及轴向速度计算值,与实验结果吻合较好。在此基础上,进一步对比分析了矩形射流和圆形射流的扩展特性,获得射流场中密度、压力、温度和速度的分布图以及涡的演化过程。计算结果表明:燃气自喷孔喷出,由于出口处压力较大,高温燃气继续膨胀产生膨胀波,膨胀波在气液界面反射形成压缩波,圆形射流的膨胀波和压缩波均比矩形射流强。燃气射流扩展过程中,由于周围液体惯性效应,气液卷吸掺混效应以及膨胀压缩波作用,圆形射流的压力场和温度场分布较矩形射流更加复杂,同时刻的圆形射流轴向扩展速度也比矩形射流小。从速度云图发现矩形射流的速度核心区比圆形射流速度核心区要短;同时从圆形射流和矩形射流不同截面流向速度分布图发现流向速度峰值均发生了偏移,但矩形射流发生偏移的区间更长,偏离距离更远。
[Abstract]:In order to study the expansion characteristics of gas jet with different orifice structure in confined liquid working medium space. The VOF(Volume of fluids-model is used to solve the gas-water coupling of the circular jet and the rectangular jet in the cylindrical liquid filled chamber respectively. The compressibility of the gas is considered. The effects of viscosity and heat exchange factors on the jet propagation characteristics are studied. The numerical simulation results of the circular jet propagation morphology and axial velocity are in good agreement with the experimental results. The distribution of density, pressure, temperature and velocity in the jet field and the evolution process of the vortex are obtained by comparing and analyzing the propagation characteristics of the rectangular jet and the circular jet. Because of the high pressure at the outlet, the high temperature gas continues to expand to produce the expansion wave, the expansion wave reflects at the gas-liquid interface to form the compression wave, the expansion wave and the compression wave of the circular jet are both stronger than the rectangular jet. The distribution of pressure field and temperature field of circular jet is more complex than that of rectangular jet because of the inertia effect of surrounding liquid, the effect of gas-liquid entrainment mixing and the effect of expansion and compression wave. The axial propagation velocity of circular jet at the same time is also smaller than that of rectangular jet. The velocity core region of rectangular jet is shorter than that of circular jet from velocity cloud diagram. At the same time, it is found that the peak velocity of flow direction is offset from the velocity distribution diagram of circular jet and rectangular jet with different cross sections, but the interval of migration of rectangular jet is longer and the distance of deviation is longer.
【作者单位】：南京理工大学能源与动力工程学院;
【基金】：国家自然科学基金项目(11372139)
【分类号】：O358
【正文快照】： 1引言水下气体射流在国防、化工、冶金、动力等工业中有广泛应用,特别由于其在潜射导弹的水下发射中的重要应用而受到高度重视,而且由于水下气体射流涉及两相流、非定常流、湍流、气液间强烈的相互作用以及流动不稳定性等复杂的流体力学问题,而成为当前流体力学界基础性的热点

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