高温烟气中半透明水滴蒸发的辐射热特性研究

Numerical Simulation of Radiation Absorption Distribution Model for Semi-transparent Water Droplet Evaporation in High Temperature Environment

喷雾水滴蒸发在高温工业烟气降温除尘中广泛应用,半透明水滴内部吸收辐射热流对蒸发传质的贡献及内部辐射传热模型的研究,成为本领域的难点问题之一。依据简化的工况,综合考虑水滴内部环流、随温度变化的热物性以及Stefan流等因素,采用两种辐射吸收模型,通过几何光学近似解析求解水滴内部导热内热源功率,并从热辐射吸收功率、瞬态温度分布等方面对高温环境中半透明水滴的辐射特性开展研究。结果表明,半透明水滴对高温烟气热辐射有较强的选择吸收特性;吸收分布模型能更精确地反映水滴内部能量分布特点;研究工况下,两种辐射模型对液滴寿命预测结果相差小于2%;不计辐射将造成预测的水滴寿命10%以上的较大误差。

The role of internal absorption of radiation heat in evaporation mass transfer and the mechanism of internal radia- tion heat transfer is one of the challenging probleras in the field. Water droplets internal circulation, thermophysieal proper- ties varied with temperature, Stefan flow and other factors are considered. The internal heat source power in water droplets is calculated by using two radiation absorption models. The radiation characteristics of the thermal radiation absorbed power of the translucent water in a high temperature environment are studied and the transient temperature distribution is investigated. The results indicate that translucent water droplets have intense heat radiation selective absorption in high temperature flue gas and that absorption distribution model aecurately shows the energy distribution characteristics in water droplet. The dif- ference of the forecast results of droplet lifetime between the two radiation models is less than 2% and no consideration of ra- diation will bring about 10% of difference for droplet life expectancy.