The fully Lagrangian approach to the analysis of particle/droplet dynamics: implementation into ANSYS Fluent and application to gasoline sprays
The fully Lagrangian approach to the analysis of particle/droplet dynamics: implementation into ANSYS Fluent and application to gasoline sprays
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颗粒/液滴动力学分析的完全拉格朗日方法：在 ANSYS Fluent 中的实现以及在汽油喷雾中的应用
DOI：
10.1615/atomizspr.2017019354
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发表时间：
2017
影响因子：
1.2
通讯作者：
M. Heikal
中科院分区：
文献类型：
--
作者：
T. Zaripov;A. K. Gil’fanov;S. Begg;O. Rybdylova;S. Sazhin;M. Heikal
将完全拉格朗日方法（FLA）应用于稀气相流中惯性粒子数密度的计算，实现到CFD软件ANSYS Fluent中。应用新版本的ANSYS Fluent对汽缸周围的稀气颗粒流动和汽油燃料喷雾中的液滴进行了建模。在稳态情况下，对于较小的斯托克斯数Stk和较小的雷诺数Re (Re = 1, Stk = 0.05)，基于平衡欧拉方法（EE）的绕流FLA预测结果与基于平衡欧拉方法（EE）的预测结果几乎相同。对于这些数值的较大值（Re = 10,100; Stk = 0.1, 0.2）， FLA预测的柱前颗粒数密度梯度值比EE预测的高。对于瞬态流动（Re = 200），两种方法都预测了高涡度区域和极低涡核区域之间的数字密度值。当Stk≥0.1时，FLA预测的最大值比EE预测的值高几个数量级。本文重点研究了液滴数密度在直喷汽油燃油喷雾中的应用。结果表明，数值模拟与实验结果具有较好的定性一致性。结果表明：直径dp = 2 μm的小液滴比直径dp = 10 μm和直径dp = 20 μm的大液滴更容易在轨迹交叉处聚集；这导致了小液滴高数量密度区域的预测。
The fully Lagrangian approach (FLA) to the calculation of the number density of inertial particles in dilute gas-particle flows is implemented into the CFD code ANSYS Fluent. The new version of ANSYS Fluent is applied to modeling dilute gas-particle flow around a cylinder and liquid droplets in a gasoline fuel spray. In a steady-state case, the predictions of the FLA for the flow around a cylinder and those based on the equilibrium Eulerian method (EE) are almost identical for small Stokes number, Stk, and small Reynolds number, Re, (Re = 1, Stk = 0.05). For the larger values of these numbers (Re = 10, 100; Stk = 0.1, 0.2) the FLA predicts higher values of the gradients of particle number densities in front of the cylinder compared with the ones predicted by the EE. For transient flows (Re = 200), both methods predict high values of the number densities between the regions of high vorticity and very low values in the vortex cores. For Stk ≥ 0.1 the maximal values predicted by FLA are shown to be several orders of magnitude higher than those predicted by the EE. An application of FLA to a direct injection gasoline fuel spray has focused on the calculation of the number densities of droplets. Results show good qualitative agreement between the numerical simulation and experimental observations. It is shown that small droplets with diameters dp = 2 μm tend to accumulate in the regions of trajectory intersections more readily, when compared with larger droplets (dp = 10 μm, dp = 20 μm). This leads to the prediction of the regions of high number densities of small droplets.