横流环境中两孔热水浮射流数值模拟研究

Study on numerical simulation of two-nozzle thermal buoyant jet in cross-flow environment

为了达到热废水排放过程中热水快速稀释的目的,采用Fluent中Realizable k-ε模型基于SIMPLEC算法,研究了热射流过程中,射流孔间距、初始流速对射流流场、温度场的影响规律。研究表明:随着射流孔间距的增大,第1孔射流对第2孔射流影响程度逐渐减弱且第2孔射流的弯曲程度随之增加;射流与横流作用促使反向涡对的产生,加快了热水与环境水体的掺混度,横断面温度场出现"肾形"分布;当相对孔间距相同时,随着射流初始流速的增加,第1、2孔射流温度衰减速率随之增大;射流初始流速相同时,射流孔间距的增加对第1孔射流轴线温度稀释度影响较小,对第2孔射流的轴线温度稀释度影响相对复杂;S/D=2时,增大热射流的初始流速,为本研究中热水快速稀释的最优方案。

In order to quick dilute the thermal waste water,the Realizable k-ε turbulence model of Fluent and SIMPLE Consistent method are utilized to investigate the effect of spacing of nozzles and initial velocity of thermal buoyant jet on flow and temperature fields. The research indicates that as the spacing of nozzles increases,the effect of the first jet on the second one gradually decreases,and blending degree of second one increases. The reverse vortex pair generated by the jet and cross flows enlarges the mixing degree of thermal waste water and environmental fluid and the distribution of temperature field of cross section is the same as the shape of kidney. As the initial velocity increases,the decay rate of axis temperature of the first and second jet increases on the condition of same spacing of nozzles. Additionally,the variations of spacing of nozzles has little impact on the dilution degree of axis temperature for the first jet but has sophisticated influence on the second one on the condition of same initial velocity. The conclusion can be drawn that when S/D = 2 and the initial velocity increased,we get the optimal solution for quick dilution of thermal waste water in this research.