Application of LES-quality criteria to internal combustion engine flows
Application of LES-quality criteria to internal combustion engine flows
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DOI：
10.1016/j.compfluid.2013.11.003
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发表时间：
2014-01
影响因子：
2.8
通讯作者：
F. Mare;R. Knappstein;M. Baumann
中科院分区：
文献类型：
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作者：
F. Mare;R. Knappstein;M. Baumann
本文着重于质量标准的适用性大涡模拟（LES）的内燃机（IC发动机），并提供了一个关键的评估这些方法。对四气门直喷式火花点火发动机在发动机工况下的数值预测结果进行了分析，在两个截面上选择了进气和压缩冲程中两个不同的曲轴转角位置。由于单元宽度是亚网格尺度（sgs）模式的基本组成部分，因此由离散化引起的误差与模式误差直接相关。虽然LES的准确度或质量指数不仅取决于网格分辨率，但可以表明网格细化导致预测质量的全局改善。两个不同的解决网格之间的比较，揭示了大的平均速度梯度，在网格细化引起的结果显着增强的区域。其中一个主要的发现是，所有成功应用的标准来计算分布的质量程度的质量可比的结果。然而，发现大的差异，在缩放和灵敏度的各种方法。一个两个网格估计的不适用性也进行了彻底的讨论。最后，一个程序来评估的比例积分长度尺度单元宽度的基础上相关函数为一个单一的点进行检查。
This paper focuses on the applicability of quality criteria to the Large Eddy Simulation (LES) of internal combustion engines (IC engines) and provides a critical assessment of some of these methodologies. The analysis is conducted on numerical predictions obtained in a 4-valve DISI (Direct-Injection Spark-Ignition) engine under motored conditions, selected at two different crank angle positions during intake and compression stroke, on two section planes. As the cell width is a fundamental component of the subgrid scale (sgs) model, the error caused by the discretization is directly related to the modeling error. Although the degree of accuracy or index of quality of an LES does not only depend on the grid resolution, it can be shown that a grid refinement leads to a global improvement in the quality of the predictions. A comparison between two differently resolved grids has revealed regions characterized by large mean velocity gradients, in which the grid refinement has caused significant enhancement of the results. One of the main findings is that all the successfully applied criteria come to qualitatively comparable results in the computed distribution of the degree of quality. Large discrepancies are found however in the scaling and sensitivity of the various methods.The inapplicability of a two-grid estimator is also thoroughly discussed.Finally, a procedure to evaluate the ratio of integral length scale to cell width based on correlation functions for a single point is examined.