高压喷射雾化液滴的二次破碎机理

采用射流界面不稳定扰动波雾化分裂理论,分析了单液滴在空气中以极高的速度运动过程中,由于液滴所受内外作用力的不平衡边界条件所产生的表面扰动;建立了液滴二次破碎色散方程,给出了单液滴在扰动波作用下发生二次破碎的最快增长率和相应的最不稳定波长,以及破碎时间和稳定液滴直径;分析了液体粘性、液滴速度对高速运动液滴不稳定性的影响,对液滴雾化机理进行了理论探讨.仿真表明:由作用于高速运动液滴表面的不平衡力,使得液滴界面产生变形加速度,这是导致液滴表面不稳定而进一步分裂的内在动因;粘性对扰动波发展有抑制作用,气液界面运动加速度是控制液滴破碎的重要因素.

Secondary breakup mechanisms of a jet-atomized liquid drop

From droplet atomization theory of instable disturb wave on jet,the surface disturb wave produced by a separate droplet moving in gas at high speed was analyzed,and the dispersion equation of secondary breakup was set up.The maximum growth rate and most unstable wave length of droplet secondary breakup were given.The breakup time and stable droplet size were also developed.Effects of liquid viscosity and jet speed upon instability of high speed droplet were illustrated and the theory investigation of droplet atomization mechanism was carried out.The results show that the unbalance forces acting on the droplet that moves in high speed will cause accelerations at the interface of gas-liquid,which is considered as the main factor that leads to instability on surface of droplet and then break into small drops;the viscosity of droplet take a suppressive role to disturb wave,and the acceleration at interface of gas-liquid is important factor in breakup of droplet.