射流作用下的吸气流动流场特性

摘要

To decrease the jet flow rate in contaminants control for a purpose of energy conservation, the flow field characteristics of exhaust flow assisted with a jet was focused. When the angleθbetween the jet and the exhaust flow ranges from 90° to 60 °,utilizing the numerical simulation,the conditions to form steady flow was determined and the changes of the centerline velocity and control region of the exhaust flow were studied. Meanwhile,based on simulation results and the analysis of the factors that affect centerline velocity and control region,two calculation methods for the decay of centerline velocity and control region of the exhaust flow with different θ were obtained. The results show that when θ is less than 70 ° ,the steady exhaust flow can not form;whenθranges from 90 ° to 70 ° ,the increase rate of the centerline velocity drops with the momentum ratio of the jet and the exhaust flow increasing, while the increase rate of the centerline velocity increases when θ decreases. Thus,the exhaust flow can be enhanced by decreasing θ,which effectively control contaminants.%为了降低射流作用下吸气流动控制污染物所需的射流量，达到节能的目的，研究了射流作用下吸气流场的特性。通过数值模拟技术研究了射流与吸气流动夹角在90°～60°变化时形成稳定吹吸流场的条件，以及汇流场轴心速度和控制范围的变化规律；同时，以数值模拟的计算结果为基础，结合对轴心速度和控制距离影响因素的分析，得出了射流和吸气流夹角θ取不同值时的轴心速度衰减计算式和汇流场控制范围计算式。研究结果表明，在θ角小于70°时不能形成稳定的吸气流场；当θ在90°～70°变化时，随着送风和排风动量比的增大，汇流场轴心速度增加的趋势减缓；随着角度θ的减小，汇流场轴心速度增加的趋势加剧。因此，可以通过减小θ来增强吸气流场，实现对污染物的有效控制。