考虑水—汽两相流增压锅炉近炉对流蒸发管的换热分析

Heat Transference Analysis of Convective Evaporation Pipe Near the Combustion Chamber of Supercharged Boiler by Considering Water-vapor Two Phase Flow

考虑近炉对流蒸发管内的水—汽两相流动,依据传热学原理,计算管内工质在不同温度不同流速下的对流换热系数。进一步考虑管外高温烟气的辐射对流换热、管外火焰的辐射换热和管内水—汽两相流的对流换热,采用有限元方法计算近炉对流蒸发管在紧急启动下的瞬态温度场;与实际温度场对比,吻合良好。提出的考虑水—汽两相流动确定对流换热系数的方法及温度场分析结果有一定参考价值。

Considering water-vapor two phase flow in convective evaporation pipe near the combustion chamber of supercharged boiler, according to the principle of heat transfer, the convective heat transfer coefficients of working medium inside pipe in different temperature and different velocity were calculated. Furthermore the transient temperature fields of convective evaporation pipe near the combustion chamber were calculated by using the finite element method, meanwhile the follow factors were taken into accounted as radiation and convection heat transfer of high temperature smoke outside pipe, radiation heat transfer of flame outside pipe and convection heat transfer of water-vapor two phase flow inside pipe. Finally, the results coincided with the actual values of temperature fields .