Large-eddy simulation of nitrogen injection at trans- and supercritical conditions
Large-eddy simulation of nitrogen injection at trans- and supercritical conditions
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DOI：
10.1063/1.4937948
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发表时间：
2016-01-01
影响因子：
4.6
通讯作者：
Hickel, Stefan
中科院分区：
文献类型：
--
作者：
Mueller, Hagen;Niedermeier, Christoph A.;Hickel, Stefan
对超临界压力下低温氮气喷入高温环境进行了大涡模拟，并对真实气体热力学模型和亚网格尺度湍流模型进行了评价。不同的SGS模型的比较-Smagorinsky模型，Vreman模型，和自适应局部反卷积方法-表明，湍流的分辨率尺度上的代表性射流破碎的位置有显着的影响，而未解决的尺度的特定建模是不太重要的整体平均流场的演变。更重要的是流体热力学状态的模型。注入的流体处于超临界或跨临界状态，并且在混合期间经历伪沸腾过程。这种流动通常表现出强烈的密度梯度，这延迟了不稳定性的增长，并可能导致湍流动能从径向到轴向流动方向的重新分布。我们评估新的体积平移方法的基础上的立方彭-罗宾逊状态方程的大涡模拟的框架。在小的额外计算成本，他们的应用程序大大提高了模拟结果相比，标准制定。此外，我们发现，流入温度的选择是至关重要的实验结果的再现，并在注射器内的热添加可以影响的平均流场与绝热注射器的结果相比。(C)2016 AIP Publishing LLC.
Large-eddy simulations (LESs) of cryogenic nitrogen injection into a warm environment at supercritical pressure are performed and real-gas thermodynamics models and subgrid-scale (SGS) turbulence models are evaluated. The comparison of different SGS models - the Smagorinsky model, the Vreman model, and the adaptive local deconvolution method - shows that the representation of turbulence on the resolved scales has a notable effect on the location of jet break-up, whereas the particular modeling of unresolved scales is less important for the overall mean flow field evolution. More important are the models for the fluid's thermodynamic state. The injected fluid is either in a supercritical or in a transcritical state and undergoes a pseudo-boiling process during mixing. Such flows typically exhibit strong density gradients that delay the instability growth and can lead to a redistribution of turbulence kinetic energy from the radial to the axial flow direction. We evaluate novel volume-translation methods on the basis of the cubic Peng-Robinson equation of state in the framework of LES. At small extra computational cost, their application considerably improves the simulation results compared to the standard formulation. Furthermore, we found that the choice of inflow temperature is crucial for the reproduction of the experimental results and that heat addition within the injector can affect the mean flow field in comparison to results with an adiabatic injector. (C) 2016 AIP Publishing LLC.