射流器气泡破碎机理及其影响因素分析

Analysis on the Breaking Mechanism and Influencing Factors of Bubbles in Jet

以射流器作为研究对象,利用Fluent软件对射流器内的流动特性进行数值模拟,根据射流器内速度、压力和湍流动能等相关参数的变化分析了射流器内气泡破碎的机理,并研究了喉嘴距和液体入口速度对射流器内气泡直径的影响。模拟结果表明,进气管的气体在喷嘴高速液体的带动下进入吸气室,两者在吸气室和喉管内剧烈碰撞混合,将大气泡剪切破碎成小气泡;喉嘴距减小,射流器内最大液体速度逐渐向右移动,吸气室内的涡流现象被抑制,能量损耗降低,当喉嘴距从40 mm减小到10 mm时,出口处的气泡平均直径从0.67 mm减小到0.45 mm;液体与气体之间的相互作用是气泡破碎的主要因素,液体入口速度增大时,湍流动能增强,液体与气体的相互作用增强,当液体入口速度增大为3.9 m/s时,出口处的气泡平均直径减小到0.36 mm。

Taking jet as the research object,the flow characteristics in the jet are numerically simulated by using Fluent software,and the mechanism of bubble breakup in the jet is analyzed according to the changes of relevant parameters such as velocity,pressure and turbulent kinetic energy in the jet.The effect of throat-mouth distance and liquid inlet velocity on the particle size of bubbles in the jet is also studied.The simulation results show that the gas in the intake pipe enters the suction chamber driven by the high-speed liquid in the nozzle,the two collide and mix violently in the suction chamber and throat pipe,shearing and breaking large bubbles into small bubbles.The throat-mouth distance decreases,the maximum liquid velocity in the axial direction of the ejector gradually moves to the right,the vortex phenomenon in the suction chamber is suppressed,and the energy loss is reduced.When the throat-mouth distance decreases from 40 mm to 10 mm,the average particle size of bubbles at the outlet is reduced from 0.67 mm to 0.45 mm.The interaction between liquid and gas is the main factor for bubble breakage.When the liquid inlet velocity increases,the turbulent flow is enhanced,and the interaction between liquid and gas is enhanced.When the liquid inlet velocity is increased to 3.9 m/s,the average particle size of bubbles is reduced to 0.36 mm.