直流蒸汽发生器全范围流动与传热数值模拟

以BW公司实际运行的直流蒸汽发生器为原型,采用两流体三流场数学模型数值模拟直流蒸汽发生器二次侧单相液对流换热区、核态沸腾区、蒸干后区域、过热区(即全范围)的流动沸腾换热现象。结果表明:本文采用的模型可较好地预测直流蒸汽发生器全范围的流动与传热特性,数值模拟结果与运行数据符合较好;蒸干后质量含汽率低于热平衡质量含汽率,结合壁温变化趋势表明直流蒸汽发生器运行过程中蒸干后区域存在一定程度的热力非平衡;随着流动换热的发展,表面传热系数迅速上升,蒸干的发生导致传热性能急剧下降,在蒸干后区域及过热蒸汽区表面传热系数缓慢上升。

Numerical Simulation of Full Range Flow and Heat Transfer in Once-through Steam Generator

The once-through steam generator operated by B&W was used as a prototype and the single-phase liquid convective heat transfer region , nucleate boiling region , post-dryout region and superheating steam region (full range ) in secondary side of an once-through steam generator were predicted by using two-fluid three-flow-field mathe-matical model .T he results show that the model used in this paper can accurately predict the full range flow and heat transfer characteristics and the numerical results are in good agreement with operational data .Post-dryout steam quality is lower than thermal equi-librium steam quality and there exists thermal non-equilibrium in post-dryout region of the running steam generator combining with the wall temperature distribution .With the development of flow and heat transfer ,surface heat transfer coefficient increases rapid-ly ,the occurrence of dryout leads to a sharp decline in heat transfer performance and then surface heat transfer coefficient rises slowly in post-dryout region and superheating steam region .