Large-eddy simulation of transcritical and supercritical jets immersed in a quiescent environment
Large-eddy simulation of transcritical and supercritical jets immersed in a quiescent environment
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沉浸在静态环境中的跨临界和超临界射流的大涡模拟
DOI：
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发表时间：
2019
期刊：
影响因子：
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通讯作者：
J. M. Cubos
中科院分区：
文献类型：
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作者：
C. Lagarza;J. Ramírez;M. Salinas;W. Vicente;J. M. Cubos
对跨临界和超临界射流的研究和理解在液体火箭、燃气轮机和柴油发动机中至关重要，因为这些设备混合室中的高压气氛会极大地改变其射流的形态。在跨临界射流中，出现了称为指状结构的新的细长实体，并表征了流体流动现象。本研究基于Mayer的实验，通过模拟两个经典案例来检验这些实体。湍流描述的大涡模拟技术与亚网格尺度模型被称为选择性结构功能模型。实际气体行为由Soave-Redlich-Kwong方程评估，输运性质由Chung方法估计。从结果中，观察到触发方位角调制的纵向调制。然后，在射流表面上形成凸起。横截面视图揭示了成对的流向涡与反向旋转方向，这是位于两侧的凸起（在致密的核心的外缘）。这些横向的、湍流的运动似乎与凸起的伸长和随后的指状结构的形成有关。反旋涡的存在与斜压涡度有关。由于瑞利-泰勒不稳定性是斜压产生的，因此它可以解释指状结构的起源。在致密核的末端发射的跨临界包裹由热屏蔽限制。在超临界情况下没有观察到指状结构。在液体火箭、燃气轮机和柴油发动机中，对跨临界和超临界射流的研究和理解是至关重要的，因为这些装置混合室中的高压气氛会极大地改变其射流的形态。在跨临界射流中，出现了称为指状结构的新的细长实体，并表征了流体流动现象。本研究基于Mayer的实验，通过模拟两个经典案例来检验这些实体。湍流描述的大涡模拟技术与亚网格尺度模型被称为选择性结构功能模型。实际气体行为由Soave-Redlich-Kwong方程评估，输运性质由Chung方法估计。从结果中，观察到触发方位角调制的纵向调制。然后，在射流表面上形成凸起。横截面视图显示对流向涡与反转的旋转方向，这是位于任一si…
The study and understanding of transcritical and supercritical jet flow are critical in liquid rockets, gas turbines, and diesel engines, as high-pressure atmospheres in these devices’ mixing chambers drastically modify the morphology of their jets. In the transcritical jet, new elongated entities called finger-like structures appear and characterize the fluid flow phenomenon. This study examines these entities by simulating two classical cases based on Mayer’s experiments. The turbulence is described by the Large-eddy simulation technique with a sub-grid scale model known as the selective structures-function model. Real-gas behavior is evaluated by the Soave-Redlich-Kwong equation, and the transport properties are estimated by Chung’s methods. From the results, a longitudinal modulation which triggers an azimuthal modulation is observed. Then, bulges are formed on the jet surface. Cross-sectional views reveal pairs of streamwise vortices with inverted rotational directions, which are located on either side of the bulges (on the outer edge of the dense core). These transversal, turbulent movements seem to be engaged with the elongation of the bulges and the subsequent formation of finger-like structures. The existence of the counter-rotating vortices is related with the baroclinic vorticity. Then, since one may refer to the Rayleigh-Taylor instability when it is baroclinically generated, this instability could give an explanation of the origin of the finger-like structures. Transcritical parcels emitted at the end of the dense core are bounded by a thermal-shield. Finger-like structures are not observed in the supercritical case. The thermal-shield is absent from the supercritical parcels.The study and understanding of transcritical and supercritical jet flow are critical in liquid rockets, gas turbines, and diesel engines, as high-pressure atmospheres in these devices’ mixing chambers drastically modify the morphology of their jets. In the transcritical jet, new elongated entities called finger-like structures appear and characterize the fluid flow phenomenon. This study examines these entities by simulating two classical cases based on Mayer’s experiments. The turbulence is described by the Large-eddy simulation technique with a sub-grid scale model known as the selective structures-function model. Real-gas behavior is evaluated by the Soave-Redlich-Kwong equation, and the transport properties are estimated by Chung’s methods. From the results, a longitudinal modulation which triggers an azimuthal modulation is observed. Then, bulges are formed on the jet surface. Cross-sectional views reveal pairs of streamwise vortices with inverted rotational directions, which are located on either si...
影响因子：
4.6
作者：
Mueller, Hagen;Niedermeier, Christoph A.;Hickel, Stefan
通讯作者：
Hickel, Stefan