Analysis of critical heat flux in vertically upward narrow rectangular channel under high pressure

The investigation of heat flux under which physical burnout of a heat transfer surface occurs is of prime importance for boiling systems with forced circulation. To avoid physical burnout under the various abnormal conditions,the nuclear reactor must be designed to operate within a safety margin. Therefore,it is of great significance to conduct research on the prediction of critical heat flux (CHF). For narrow rectangular channel, heat exchange characteristics are obviously different from those in conventional flow channels. In this research, Euler’s two-fluid model is used to predict the CHF value in a narrow rectangular channel with a vertical upward pressure, and the predicted results are compared to the experimental data obtained at the Betties nuclear power plant, the error between the predicted results and the experimental data is less than 20%, which shows that the model has high accuracy in predicting the CHF of the narrow rectangular channel under high pressure. Besides the above, sensitive analysis of two-phase sub-model, width to diameter ratio of flow channel and various heating length are conducted in this research,which indicates that there are considerable impact on the predicting CHF value. • Conducted numerical simulations of CHF in narrow rectangular channels. • Performed three-dimensional numerical simulations of CHF under high-pressure conditions. • Carried out sensitivity analysis on sub-models.