ABSTRACT

In the design process of a steam generator, a porous-media-approach computational code is utilized for simulating three-dimensional two-phase flow behavior in the secondary side of steam generators. For the design of next-generation steam generators, the advanced thermal-hydraulic analysis code based on the two-fluid model has been developed by implementing constitutive equations into the ANSYS fluent. For code validation, experiments using two-phase simulant fluids were performed to collect data in a simulated steam generator with a triangular tube array. The simulant two-phase flow system selected in the experiment was an adiabatic sulfur hexafluoride gas and liquid ethanol system, which allowed us to achieve the density ratio of prototypic steam-water flow with low pressure (=0.68 MPa). In the experiment, void fraction and gas–liquid interfacial velocity distributions along U-tubes were measured. The code validation was conducted by analyzing code predictions for measured distributions of void fraction and interfacial velocity under prototypic full load and partial load conditions, i.e., 50–80% flow rate conditions. Their bias and random errors were evaluated. The reasonable random errors demonstrated the validity of the newly developed code based on the two-fluid model in terms of predictions of void fraction and interfacial velocity in the secondary side of steam generators.

摘要

在蒸汽发生器的设计过程中，利用多孔介质方法计算代码来模拟蒸汽发生器二次侧的三维两相流动行为。对于下一代蒸汽发生器的设计，通过在 ANSYS fluent 中实施本构方程，开发了基于双流体模型的高级热工水力分析代码。为了验证代码，使用两相模拟流体进行了实验，以在具有三角形管阵列的模拟蒸汽发生器中收集数据。实验中选择的模拟两相流系统是绝热的六氟化硫气体和液体乙醇系统，这使我们能够在低压（=0.68 MPa）下实现原型蒸汽-水流的密度比。在实验中，测量了沿 U 形管的空隙率和气液界面速度分布。代码验证是通过分析在原型满载和部分负载条件下，即 50-80% 流速条件下测量的空隙率和界面速度分布的代码预测来进行的。评估了他们的偏差和随机误差。合理的随机误差证明了新开发的基于双流体模型的代码在蒸汽发生器二次侧空隙率和界面速度预测方面的有效性。评估了他们的偏差和随机误差。合理的随机误差证明了新开发的基于双流体模型的代码在蒸汽发生器二次侧空隙率和界面速度预测方面的有效性。评估了他们的偏差和随机误差。合理的随机误差证明了新开发的基于双流体模型的代码在蒸汽发生器二次侧空隙率和界面速度预测方面的有效性。