静止液体中顶部浸没管口处气泡形成的数值预测

综合分析气泡的受力,基于动力学平衡建立了长大-脱离的两阶段气泡运动方程.对顶部浸没管口处形成气泡的尺寸进行直接数值预测.分析了气体流量、管口内外直径以及表面张力、液体粘度和液体密度对气泡尺寸的影响.并将计算结果与实验结果进行了对比,两者吻合较好,变化趋势一致.研究表明:气泡尺寸随着气体流量以及管口的内径和外径的增加而增大.气体流量和管口内外径都是影响气泡尺寸的重要因素;在一定气体流量下,气泡的直径随着表面张力和液体粘度的增加而增大,而随着液体密度的增加而减少;随着气体流量的增加,液体粘度对气泡尺寸的影响增强,而液体密度以及表面张力对气泡尺寸的影响减弱.

Numerical prediction of bubble formation from top-submerged nozzle in stagnant liquid.

Bubble size is one of the key parameters in the process of gas inject into liquid through vertically downward top-submerged nozzles.Based on the overall force balance on the bubble a two-stage model is established for predict the size of bubbles formation from a downward top-submerged nozzle in stagnant liquid.The effects of gas flow rate,inner and outer nozzle diameters,surface tension,density and viscosity of liquid on the size of bubbles formed are analyzed. The predicted bubble size is in good agreement with experimental results.The results show that the bubble size increases with increasing in gas flow rate,inner and outer nozzle diameter.Thus the gas flow rate,nozzle inner and outer diameter are important influential factors on bubble size.Under constant gas flow rate, the diameter of bubble decreases with the increase of the density of liquid,whereas increases with increasing liquid viscosity and surface tension.With the increase of gas flow rate,the influences of liquid viscosity on size of bubble increase,but the influences of liquid density and surface tension on the bubble size weaken gradually.