边界层网格尺度对泵站流场计算结果影响研究

发布时间：2019-01-05 19:14

【摘要】：壁面处的y+值是体现壁面边界层网格尺度的主要参数,对泵站流场数值计算结果有重要影响。为明确不同计算目标对y+的依赖性,以一泵站为研究对象,在网格数量无关性检查的基础上,从网格划分难易程度、数值计算精度和效率方面提出3种网格划分方案:全局非结构网格方案,指定边界层高度的全局非结构网格方案,以及指定边界层高度的分块结构网格方案,对应的y+值分别为10~2 000、10~1 000、10~500。方案二与方案三在模拟得到的流速分布均匀度方面几乎没有差别,涡量场的漩涡数量、涡量值和漩涡核心区分布位置也非常接近,而方案一则与之相差较大。研究发现,当只需了解泵站宏观水力性能时,可采用简单易行的方案一所对应的网格方案,y+范围可适当放宽到0~2 000;当要预测进水部分流场的流动特性,特别是漩涡分布特性时,需确保y+位于1 000以内,可采用方案二的网格方案;若对进水流场进行详细研究,或者进行除涡装置的研究时,则需使得整个计算域的y+满足30~500的要求,即采用方案三的网格方案。
[Abstract]:The y value of the wall is the main parameter reflecting the grid scale of the wall boundary layer, which has an important influence on the numerical results of the flow field of the pump station. In order to determine the dependence of different computing targets on y, a pumping station is taken as the research object. Based on the inspection of the independence of grid quantity, it is easy to divide the grid. In terms of numerical calculation accuracy and efficiency, three mesh schemes are proposed: global unstructured mesh scheme, global unstructured mesh scheme with specified height of boundary layer, and block structured grid scheme with specified height of boundary layer. The corresponding y values are 102000, 101000 and 10500, respectively. There is almost no difference in the uniformity of velocity distribution between scheme two and scheme three. The number of vortices in the vorticity field, the vorticity value and the distribution of vortex core are very close to each other, but the difference between scheme 1 and scheme 1 is quite large. It is found that when only the macroscopic hydraulic performance of pump stations is known, a simple and easy grid scheme can be adopted, and the y range can be extended to 0 / 2 000; In order to predict the flow characteristics of the influent part, especially the vortex distribution, it is necessary to ensure that y is less than 1 000, so the grid scheme of scheme 2 can be adopted. If the influent flow field is studied in detail or the vortex removal device is studied, it is necessary to make the y of the whole computing domain meet the requirement of 30g / 500, that is, the grid scheme of scheme 3 is adopted.
【作者单位】：中国农业大学水利与土木工程学院;北京市供水管网系统安全与节能工程技术研究中心;
【基金】：国家自然科学基金项目(51139007) 国家科技支撑计划项目(2015BAD20B01)
【分类号】：TV675

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