摘要
对k-ε双方程湍流模型进行浮力修正,编制了计算程序并对冷却水侧向表层排放出流后的特性进行模拟,计算结果与经验公式吻合较好。在此基础上,探讨了射流出口密度弗劳德数F_r对冷却水侧向表层排放特性的影响。结果表明,F_r越小,射流流核越短,沿上游来流方向的热输移长度越大;同时计算发现,存在-个合适的排水口面积使得射流掺混效果最佳。
This paper aims to simulate water cooling process by using a 3-D numerical model. As is known, temperature is an essential factor for water environment evaluation, and, therefore, it is necessary to predict the water temperature more or less accurately. However, it was not until very recently that not enough attention had been paid to the mathematical model building, especially to the gradual maturity of 1-D and 2-D numerical models of temperature. Seeing the situation, a k -ε two equation turbulent model has been taken into detailed consideration in this paper with buoyancy-correction with its calculation method for the cooling water offered from lateral surface. To ameliorate the evaluation, we have also introduced the finite volume method for discretization of the control equations and the velocity-pressure in coupling with the SIMPLE methods. In addition, the wall-function method is also applied to the study of the wall boundary conditions. Thus, the calculation program has been worked out simultaneously. As a result, the calculated and empirical formula prove to be highly congenital, feasible as well as practical for establishing mathematical models and calculation methods. Furthermore, the pa- per has also discussed the effect of the exit densimetric Froude number （Fr） on the drainage from the lateral surface. The calculated resuits show that the smaller the Fr, the shorter the flow core, and the greater the length of the heat transport to the direction of inflow from upstream, which helps to find that there is a suitable outfall area in making the mixing of jets desirable. The analysis and computation resuits have reference value to actual projects. In practical project, based on both the discharge of upstream and cooling water, and also the energy of jets discharged into environment per unit time, a suitable drainage outlet area can be chosen to make the cooling water and environment mix best.
出处
《安全与环境学报》
CAS
CSCD
北大核心
2009年第2期40-43,共4页
Journal of Safety and Environment
关键词
环境科学
冷却水
侧排放
三维数值模拟
k—ε模型
environmental science
cooling water
side discharge
3-D turbulent modeling
k -ε model
