立式三分螺旋折流板冷凝器的数值计算

Numerical Simulation of Vertical Trisection Helical Baffle Condensers

利用立式三分螺旋折流板冷凝器之倾斜折流板的疏液强化凝结传热是一种创新的改进.以数值模拟的方式,研究立式三分螺旋折流板冷凝器模型中倾斜折流板的疏液和螺旋通道内的流动汽液分离对凝结换热强化的影响.模拟结果表明,凝结换热效果随折流板倾斜角度减小而强化,且在含不凝性气体时,倾斜角为15°,25°和35°的3种三分螺旋折流板冷凝器方案和弓形折流板换热器方案比无折流板光管束Nusselt凝结模型方案的平均凝结换热系数分别高出89.7%,75.7%,58.2%和33.1%.

A novel structure of vertical trisection helical baffle feed water heater can enhance the heat transfer by effectively draining the condensate with inclined baffles and separating water droplets from vapor due to centrifugal force in helix channels.The draining film effect of inclined baffles and the impact of spiral flow on condensation heat transfer in a vertical trisection helical baffle condenser were numerically simulated.These simulation schemes include the Nusselt condensation models under the conditions of pure steam or in presence of non-condensable gas,the vertical trisection helical baffle condenser schemes with baffle inclined angles of 15°,25°and 35° and the segmental baffle scheme in the presence of non-condensable gas.The results demonstrate that the condensation heat transfer increases with the decrease of inclined angle of helical baffles, and in the presence of non-condensable gas,the average condensation heat transfer coefficients of three trisection helical baffle schemes with inclined angles of 15°,25°and 35°and the segmental baffle scheme are 89.7%,75.7%,58.2%and 33.1% higher than that of the bare tube bundle of Nusselt condensation model.