直接接触式湿烟气余热回收热质传递数值研究

在Fluent软件中,基于欧拉-拉格朗日方法和自定义函数(UDF),构建了三维稳态模型,并在离散相模型(DPM)基础上,耦合欧拉壁膜模型(EWF)对冷凝室内湿烟气与喷淋液滴及周围壁面间的凝结传热进行数值模拟研究。研究结果表明,DPM与EWF耦合可以更精确地模拟湿烟气在冷凝室内的凝结换热;入口烟气流速越大,冷凝室高度越低,则出口烟气温度和出口烟气水蒸气体积分数越高,烟气换热效率越低,且变化幅度逐渐减缓;冷凝室高度越高,则壁面湿烟气凝结量越大,但随着入口烟气流速增大,冷凝室高度对凝结换热的影响逐渐减弱,换热效率提高幅度也明显减小。

Numerical Study on Heat and Mass Transfer of Direct Contact Wet Flue Gas Waste Heat Recovery

In the Fluent software,a three-dimensional steady-state model was constructed based on the Euler-Lagrangian method and user defined function(UDF).And the Discrete Phase Model(DPM) coupled with the Euler Wall Film(EWF) model is used to conduct a numerical simulation study on condensation heat and mass transfer between wet flue gas and spray droplets and the surrounding walls in the condensing chamber.The simulation results show that the coupling of DPM and EWF model can more accurately simulate the condensation heat transfer of wet flue gas in the condensing chamber.The greater the inlet flue gas flow rate and the lower the height of the condensing chamber,the higher the outlet flue gas temperature and water vapor volume fraction,the lower the flue gas heat exchange efficiency,and the range of change gradually slows down;the higher the height of the condensing chamber,the greater the condensation amount of wet flue gas on the wall. However,with the increase of the inlet flue gas flow rate,the influence of the height of the condensing chamber on the condensation heat transfer gradually weakens,and the increase of heat exchange efficiency with the increase of the height of the condensing chamber is significantly reduced.