Numerical study of cavitation in cryogenic fluids
Numerical study of cavitation in cryogenic fluids
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DOI：
10.1115/1.1883238
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发表时间：
2005-03-01
影响因子：
2
通讯作者：
Ahuja, V
中科院分区：
文献类型：
--
作者：
Hosangadi, A;Ahuja, V
给出了液氮和液氢中空化的数值模拟；它们代表了流体在接近其临界温度时运行的更广泛的一类问题，并且空化的热效应是重要的。描述了一种可压缩的多相配方，它考虑了流体的能量平衡和可变的热力学性质。当热效应变得显著时，空腔的物理特性发生了根本变化；空腔变得更加多孔，界面不那么明显，它表现出更大的扩展，同时长度变短。在B因子理论的变种中假设的传热模型，其中汽化由汽液界面的粘性热扩散控制，被证明是一个较差的低温流体的近似模型。相反，这里给出的结果表明，空腔是由直接对流进入空腔的质量和液体穿过空腔界面时发生的汽化来维持的。本文对流过水翼的流动进行了参数研究，并与Hord(1973，《液体冷冻剂II-水翼中的空化》，NASA CR-2156)的实验数据进行了比较；自由流速度被证明是影响热压降水平的一个独立参数。
Numerical simulations of cavitation in liquid nitrogen and liquid hydrogen are presented; they represent a broader class of problems where the fluid is operating close to its critical temperature and thermal effects of cavitation are important. A compressible, multiphase formulation that accounts for the energy balance and variable thermodynamic properties of the fluid is described. Fundamental changes in the physical characteristics of the cavity when thermal effects become significant are identified; the cavity becomes more porous, the interface less distinct, and it shows increased spreading while getting shorter in length. The heat transfer model postulated in variants of the B-factor theory, where viscous thermal diffusion at the vapor-liquid interface governs the vaporization, is shown to be a poor approximation for cryogenic fluids. In contrast the results presented here indicate that the cavity is sustained by mass directly convecting into it and vaporization occurring as the liquid crosses the cavity interface. Parametric studies for flow over a hydrofoil are presented and compared with experimental data of Hord (1973, "Cavitation in Liquid Cryogens II-Hydrofoil, " NASA CR-2156); free-stream velocity is shown to be an independent parameter that affects the level of thermal depression.