【摘要】 针对600 MW火电机组的低温省煤器堵塞问题,提出了低温省煤器旁路改造方案。根据并联管道的性质和流固耦合传热理论,对增设旁路的低温省煤器系统进行了数值模拟,得到不同进口烟气流速和旁路规格下系统烟气进、出口压差和换热情况,并拟合出旁路压头损失与系统烟气进、出口压差的关系。结果表明:当旁路夹角不变时,旁路面积占比从20%增大到40%,烟气流动性改良系数增幅均大于20%;烟气流动性改良系数随旁路夹角的增大而减小;系统烟气进、出口压差随旁路压头损失的增大而增大。更多还原

【Abstract】 To solve the problem of blockage existing in the low-temperature economizer of a 600 MW thermal power unit, a bypass retrofit scheme was proposed for the economizer. According to the flow characteristics in parallel pipes and the fluid-solid coupling heat transfer theory, numerical simulations were conducted on the low-temperature economizer system with a bypass line added, during which, the pressure drop and heat transfer characteristics of the flue gas were obtained under different inlet flue gas velocities and bypass specifications, while the relationship between the bypass head loss and the flue gas pressure drop was fitted. Results show that keeping the bypass angle constant, as the ratio of bypass flow area increases from 20% to 40%, the improvement coefficient of flue gas fluidity would be increased by more than 20%, which would reduce with the rise of bypass angle. Meanwhile, the flue gas resistance in the system increases with the rise of the bypass head loss.更多还原