论文标题

一种一致的流体量方法,用于直接模拟汽化滴的空气动力分解

A consistent volume-of-fluid approach for direct numerical simulation of the aerodynamic breakup of a vaporizing drop

论文作者

Boyd, Bradley, Ling, Yue

论文摘要

在这项研究中已经开发了一个新型的模拟框架,用于直接对蒸发滴的空气动力分解的直接数值模拟。使用一致的几何量量法解决了与相变的界面多相流有关的。散装流体是粘性的,在界面处与表面张力不可压缩。新开发的数值方法已在Basilisk求解器中实现,其中自适应OCTREE/QUADTREE网格用于空间离散化,从而可以在用户定义的区域中动态精炼网格的灵活性。模拟框架通过一系列基准案例进行了广泛的验证,包括1D Stefan和吸吮问题,在过热液体中的3D球形气泡的生长以及2D膜沸腾问题。模拟结果与精确解决方案和先前的数值研究非常吻合。进行了2D轴对称模拟,以在高温自由流中较低的Weber数量的移动液滴的蒸发。计算出的量损失速率与滴蒸发的经验模型非常吻合。最后,经过验证的求解器用于模拟丙酮滴的空气动力分解,以高韦伯数。进行了完全的3D模拟,并准确解决了滴的形态演化。由于下降变形和分解,发现汽化速率显着提高。下降量的时间降低了,并且比球形下降的经验相关性高得多。

A novel simulation framework has been developed in this study for the direct numerical simulation of the aerodynamic breakup of a vaporizing drop. The interfacial multiphase flow with phase change is resolved using a consistent geometric volume-of-fluid method. The bulk fluids are viscous and incompressible with surface tension at the interface. The newly-developed numerical methods have been implemented in the Basilisk solver, in which the adaptive octree/quadtree mesh is used for spatial discretization, allowing flexibility in dynamically refining the mesh in a user-defined region. The simulation framework is extensively validated by a series of benchmark cases, including the 1D Stefan and sucking problems, the growth of a 3D spherical bubble in a superheated liquid, and a 2D film boiling problem. The simulation results agree very well with the exact solution and previous numerical studies. 2D axisymmetric simulations were performed to resolve the vaporization of a moving drop with a low Weber number in a high-temperature free stream. The computed rate of volume loss agrees well with the empirical model of drop evaporation. Finally, the validated solver is used to simulate the aerodynamic breakup of an acetone drop at a high Weber number. A fully 3D simulation is performed and the morphological evolution of the drop is accurately resolved. The rate of vaporization is found to be significantly enhanced due to the drop deformation and breakup. The drop volume decreases nonlinearly in time and at a much higher rate than the empirical correlation for a spherical drop.

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