大坝下游水体溶解气体浓度超饱和模型研究进展  

Progress of Model Studies on Total Dissolved Gas Supersaturation Downstream of Sluicing Dam

作　　者：陈雪巍[1] 程香菊[1] 詹威[1] 

机构地区：[1]中山大学工学院,广州510275

出　　处：《科技导报》2009年第17期101-105,共5页Science & Technology Review

基　　金：国家自然科学基金项目(50609011);中国水利水电科学研究院开放研究基金项目

摘　　要：大坝泄水建筑物过流水体强烈掺气容易导致下游水体中溶解气体(TDG)浓度超饱和,使下游一定水深处的水生生物遭受气泡病的危害,因此有必要对大坝水垫塘内强紊动水体的气液传质问题进行研究。本文对国内外TDG浓度超饱和模型的发展进行了简要的评述,分析总结了TDG输运方程、气液双流体模型、气泡界面传质系数、传质面积、气泡直径、掺气浓度和有效饱和浓度等的研究进展及其优缺点。其突出的问题是对气泡动力学认识不够,气泡数量、气泡聚并与破碎、气泡尺寸、气含率和气泡速度的求解仍存在诸多假设和尚需实验验证的系数。预测模型发展受到湍流模型、气泡表征方法和TDG输运方程的限制。本文为更好地完善水体TDG浓度超饱和模型提供了参考和依据。The strong air entrainment is related with the hydrostatic force of the water column, which increases the pressure within the entrained bubbles. This phenomenon may lead to the Total Dissolved Gas （TDG） supersaturation downstream of spillway and aquatic animals may suffer from gas bubble diseases at a certain water depth. Thus, it is necessary to study the gas-liquid mass transfer of turbulent water in still basins. The paper reviews some representative models of the total dissolved gas concentration both at home and abroad, and discusses the development of the TDG transport equation, two-fluid model, mass transfer coefficient, interfacial area, bubble size, gas volume fraction, and the effect of saturation concentration. However, in these models the air bubble hydraulics is not well represented. To determine the number and size of air bubbles, the air concentration and the air bubble rising velocity, some assumptions are still necessary. Some parameters in the models remain to be verified by experiments. Bubble breakup and coalescence are assumed to be negligible since neither bubble size nor bubble distribution are actually measured in the field. The predictive capability of the models is limited by the modeling accuracy of the different terms in the turbulence, bubble and TDG transport equation. This paper provides some food for thought for further development of the numerical models of the TDG supersaturation and the methods for solving supersaturation problems.

关 键 词：数值模型 总溶解气体 超饱和 气泡传质 

分 类 号：TV131.3[水利工程—水力学及河流动力学]