高炉渣液滴破碎过程数值模拟

Numerical simulation of the breakup of high temperature blast furnace slag droplet

采用流体体积法(VOF)、RNG k-ε湍流模型和凝固/熔化模型对高炉渣液滴二次破碎过程进行数值模拟,获得了高炉渣液滴临界状态下袋式破碎过程,分析了高炉渣液滴传热过程对破碎过程的影响,研究了高炉渣液滴破碎的临界韦伯数.结果表明:在气动力驱动下,高炉渣液滴会发生形变,表面压力的波动可导致液滴破碎;传热过程仅使高炉渣表面温度略微降低,对黏度影响不大,因此高炉渣液滴传热过程对破碎过程的影响可忽略不计;高炉渣液滴的初始粒径越大、气流速度越大,破碎效果越好;在1773 K的初始温度下,高炉渣液滴发生破碎的临界韦伯数约为15.5;当液滴的黏度增加时,奥内佐格数增大,破碎的临界韦伯数也增大,通过拟合可得到高炉渣主要黏度范围内的奥内佐格数与临界韦伯数的关系式.

The secondary breakup process of blast furnace slag droplets was numerically simulated with volume of fluid(VOF),RNG k-εturbulence model and Solidification/Melting model,which obtained the bag breakup process of slag droplet under critical condition.Besides,the effect of heat transfer on droplet breakup process were analyzed and the critical We of blast furnace slag droplet was obtained.Results indicate that deformation of slag droplet is driven by aerodynamic force while surface pressure fluctuations lead to droplet breakup.And the temperature of slag surface decreases lightly having little effect on the viscosity due to heat transfer,which means the influence of heat transfer of slag droplet on the breakup can be ignored.Besides,with the increase of diameter of droplet and velocity of air,the breakup effect is better.The critical We of blast furnace slag droplet is 15.5 when the temperature is 1773 K.Furthermore,Oh increasing with the increase of viscosity of droplet,which leads to the increase of critical We.The relation between the critical We and Oh under the main viscosity range of blast furnace slag is obtained.