The critical heat flux (CHF) is essential to the operational safety of nuclear power plants (NPP), and it plays a vital role in the thermal-hydraulic and structural design of a fuel assembly. In this study, the commercial computational fluid dynamics package STAR-CCM+ was used to predict the departure from the nucleate boiling (DNB) phenomenon. Based on the Eulerian two-fluid model and the extended Rensselaer Polytechnic Institute (RPI) wall boiling model combined with the Weisman-Pei bubble crowding model, the DNB phenomenon was investigated for two coolants (water and R134a) with different geometric structures and working conditions. The results demonstrated that one set of Eulerian two-fluid models could accurately predict the CHF within a certain range of working conditions. The CHF value calculated in this study show good agreement with the experimental measured CHF data, which indicated that the Eulerian two-fluid model had a good application prospect for CHF prediction. The observed mean error was less than 10%. The results of this study may contribute to an advanced boiling model development for CHF prediction in complex geometric structures such as fuel assembly. In addition, these results demonstrated that it was feasible to use the refrigerant R134a, which had a low critical pressure and low latent heat of vaporization, as the modeling fluid to replace water, which had a high latent heat of vaporization and a high critical pressure in the experimental study.

临界热通量（CHF）对于核电厂（NPP）的运行安全至关重要，在燃料组件的热工液压和结构设计中起着至关重要的作用。在这项研究中，使用商业计算流体动力学软件包STAR-CCM +来预测偏离核沸腾（DNB）现象。基于欧拉二流体模型和扩展的伦斯勒理工学院（RPI）壁沸腾模型并结合Weisman-Pei气泡拥挤模型，研究了两种几何结构和工作条件不同的冷却剂（水和R134a）的DNB现象。结果表明，一套欧拉二流体模型可以在一定工作条件下准确预测CHF。本研究计算的CHF值与实验测得的CHF数据吻合良好，表明欧拉二流体模型在CHF预测中具有良好的应用前景。观察到的平均误差小于10％。这项研究的结果可能有助于为复杂几何结构（例如燃料组件）中的CHF预测开发先进的沸腾模型。另外，这些结果表明，使用具有低临界压力和低汽化潜热的制冷剂R134a作为替代具有高蒸发潜热和高临界压力的水的建模流体是可行的。在实验研究中。观察到的平均误差小于10％。这项研究的结果可能有助于为复杂几何结构（例如燃料组件）中的CHF预测开发先进的沸腾模型。另外，这些结果表明，使用具有低临界压力和低汽化潜热的制冷剂R134a作为替代具有高蒸发潜热和高临界压力的水的建模流体是可行的。在实验研究中。观察到的平均误差小于10％。这项研究的结果可能有助于为复杂几何结构（例如燃料组件）中的CHF预测开发先进的沸腾模型。另外，这些结果表明，使用具有低临界压力和低汽化潜热的制冷剂R134a作为替代具有高蒸发潜热和高临界压力的水的建模流体是可行的。在实验研究中。