On the Validation of Large Eddy Simulation Applied to Internal Combustion Engine Flows Part II: Numerical Analysis
On the Validation of Large Eddy Simulation Applied to Internal Combustion Engine Flows Part II: Numerical Analysis
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DOI：
10.1007/s10494-013-9472-x
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发表时间：
2014
期刊：
影响因子：
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通讯作者：
M. Baumann;F. Mare;J. Janicka
中科院分区：
文献类型：
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作者：
M. Baumann;F. Mare;J. Janicka
在内燃机中，特征缸内流场是必不可少的，并且显著地有助于发动机效率和性能。本文描述了一台四冲程单缸研究用发动机的流场数值研究。在选定的曲柄角和在这项工作中获得的结果进行了讨论的实验和数值数据之间的定量和定性的比较。通过统计流动特性来分析平均流场和瞬时流场。为了研究高阶统计速度矩和获得洞察的物理过程中描述的发动机流动结构，多循环大涡模拟（LES）进行了两个不同的空间分辨率的网格。根据进气过程中各个循环的Q准则，通过涡结构等值面，也可显示出流动的三维结构。为了评估分析并验证计算网格适用于LES模拟的性能，沿感兴趣的平面沿着评估湍流分辨率M和sgs粘度与层流粘度的比率。从数值预测中提取的流场的统计数据的直接比较表明，在相同的配置进行的测量非常好的协议。然而，已经观察到离散性，特别是在速度分量的较高时刻。虽然这可以主要归因于有限数量的统计样本（50 LES周期）在模拟过程中收集，进一步的调查肯定是必要的，以评估建模和空间分辨率问题的相关性。
In internal combustion engines, the characteristic in-cylinder flow field is essential and significantly contributes to engine efficiency and performance. This paper describes the numerical investigation of the flow field in a motored 4-stroke, single-cylinder research engine. Quantitative and qualitative comparisons between experimental and numerical data have been performed at selected crank angle and results obtained in this work are discussed. Statistical flow properties are examined to analyze the averaged and instantaneous flow field. In order to investigate higher order statistical velocity moments and gain insight in the physical processes describing the engine flow structure, multi-cycle Large Eddy Simulation (LES) was carried out on two meshes with different spatial resolution. The three-dimensional structure of the flow has been also visualized by means of iso-surfaces of vortical structures, based on the Q criterion for individual cycles during intake. In order to assess the analysis and to verify that the computational mesh is applicable for the performance of LES simulations, the turbulence resolution M and the ratio of sgs-viscosity to the laminar viscosity were evaluated along the planes of interest. A direct comparison of the statistics of the flow field extracted from the numerical predictions shows a very good agreement with measurements conducted in the same configuration. Discrepancies have been however observed, in particular in the higher moments of the velocity components. Whilst this can be attributed mostly to the limited number of statistical sample (50 LES cycles) collected during the simulation, further investigation is certainly necessary to assess the relevance of modeling and spatial resolution issues.