基于混合框架亚格子掺气模型的明渠自掺气均匀流数值模拟  

Numerical Simulation of Self-aerated Uniform Open Channel Flow Using Mixture Framework Based Sub-grid Aeration Model

作　　者：董宗师 蔡芳 李勇泉 DONG Zong-shi;CAI Fang;LI Yong-quan(Changjiang Survey,Planning,Design and Research Co.,Ltd.,Wuhan 430010,China;Basin Hub Operation Management Center of China Three Gorges Group Co.,Ltd.,Yichang 443134,China)

机构地区：[1]长江设计集团有限公司,湖北武汉430010 [2]中国长江三峡集团有限公司流域枢纽运行管理中心,湖北宜昌443134

出　　处：《水电能源科学》2022年第7期146-150,共5页Water Resources and Power

基　　金：中国博士后科学基金资助项目(2021M692754)。

摘　　要：为探究掺气模型模拟明渠自掺气水流的可靠性,采用亚格子掺气模型、变密度模型和漂移流模型相结合的混合框架亚格子掺气模型对3种典型坡度下的明渠自掺气均匀流进行了数值模拟。计算结果表明,所用模型可较好地计算两相流的速度分布,在缓坡下难以捕捉掺气浓度高于0.3的区域,导致计算得到的断面平均掺气浓度较低;而在中坡和陡坡下所用模型的扩散性高于实际,进而会得到高于实际的断面平均浓度;中坡和陡坡情况下计算的气泡绝对大小和在断面上的分布规律较为合理,但缓坡情况下的气泡直径分布规律性较差。总体来看,该模型应用于中坡和陡坡明渠的掺气计算可靠性较高,但仍需一定的参数校验。而对于缓坡明渠的计算结果的可靠性则较差。In order to test the reliability of aeration model for simulation of self-aerated open channel flow,the sub-grid aeration model,variable density model and the drift-flux model were used to simulate the uniform self-aerated open channel flow under three kinds of typical slope gradients.The results show that the model can calculate the velocity distribution of the two-phase flow well.Moreover,the models failed to capture the high air concentration region under gentle slope where air concentrations are above 0.3,resulting in a lower depth-averaged air concentration.While under moderate and steep slopes,the models showed a higher diffusion of air bubbles and thus resulted in higher depth-averaged air concentration than that in the experiment.It is also discovered that the absolute sizes and distribution of the air bubbles are reasonable except the bubble diameter distribution under the gentle slope.All in all,the performances of these models for moderate and steep slopes applications are reliable,but some parameter calibrations are still required to get better results.However,the reliability of the models for gentle slopes applications remains poor.

关 键 词：明渠 掺气 混合框架 亚格子掺气模型 数值模拟 

分 类 号：TV135.2[水利工程—水力学及河流动力学]