高温烟气中水滴非等温蒸发的数值模拟研究

Computational Studies of Non-isothermal Droplet Evaporation in Hot Fuel Gas

喷雾蒸发冷却技术在钢厂转炉和电炉烟气处理工程中有广泛的应用,对于喷雾蒸发机理的研究是建立在单个水滴蒸发的研究基础之上的。本文依据简化的工况,考虑了水滴内部环流、蒸发过程中的变物性、Stefan流,建立了单水滴蒸发的非等温模型,研究了对流环境下高温气体中水滴的蒸发特性,获得了不同环境温度、水滴初始条件下水滴半径和温度等参数的变化规律。研究发现,水滴的蒸发过程存在快速加热和稳态蒸发两个阶段;初始直径对瞬态阶段的影响较大,而对稳态阶段影响不大;水滴越大,滑移速度对蒸发的影响也越大。对喷雾水滴蒸发特性的数值模拟,为进一步研究液滴群在高温烟气中的蒸发提供了更可靠的方法。

Evaporative cooling technology is widely used for treating fuel gas which is from converter or electric furnace,and the research of spray evaporation mechanism is based on the evaporation of single droplet.Based on the simplified working conditions,considering the internal-circulation、varying thermophysical parameters and Stefan flow,non-isothermal model is presented in this paper.Evaporation-characteristic in hot gas flow is researched to obtain the variation of diameter and temperature with different conditions.The research finds that evaporation process divides into two phases,which are rapid-heating and stationary-evaporation stage;initial diameter greatly impact the transient stage,but has little effect on the latter stage;the influence of slip velocity increases with the increasing initial diameter.Simulation of evaporation characteristic provides a more reliable method for further study of droplet group in hot fuel gas.