直管式直流蒸汽发生器不同运行参数下两相流压降预测

摘要

将B&W公司的直流蒸汽发生器进行简化,采用常热流边界条件进行不同运行参数下直流蒸汽发生器二次侧流动与换热过程数值模拟,并与经典摩擦压降经验关联式进行对比.结果表明:Martinelli-Nelson关联式更适用于预测蒸干发生时两相流的摩擦压降;摩擦压降随质量含汽率增加整体呈现上升趋势,蒸干发生时摩擦压降的变化率明显增大;管内气液两相流摩擦压降随质量流量和热通量增加而增大,随运行压力增大而减小.其中质量流量、运行压力对摩擦压降的影响较明显,热通量对其影响较小.%The once-through steam generator which was designed by B & W company was simplified.The flow and heat transfer process in the secondary side under different conditions for the once-through steam generator was numerically simulated based on constant heat flux,and the numerical results were compared with the classic correlations of frictional pressure drop.The results show that Martinelli-Nelson correlation can be used to predict the two-phase frictional pressure drop along with the occurrence of dryout.The frictional pressure drop increases with the increasing steam quality,and the frictional pressure drop gradient obviously increases when the dryout happens.The two-phase frictional pressure drop within the tube increases with the increasing mass flow rate and heat flux,while decreases with the rising operating pressure.The effect of mass flow rate and operating pressure on friction pressure drop is obvious,while the heat flux has little effect on the friction pressure drop.