A three-dimensional numerical calculation was carried out on the departure from nucleate boiling(DNB)type critical heat flux(CHF)in a vertical circular tube under different rolling conditions.The Euler two-phase flow model and the non-equilibrium wall boiling model were used.By comparing the simulated CHF values of static tubes with experimental values,a sensitivity analysis of different wall boiling sub-models was completed.The CHF of a vertical tube with sinusoidal simple harmonic rolling motion is predicted for 15 combinations of amplitude and period.The results show that all rolling conditions lead to the early occurrence of DNB.In the most"violent"rolling situation,the value of CHF is the smallest.The temperature and heat transfer coefficient in the tube will change periodically with the rolling motion.Within a period,larger amplitude and smaller period will cause the heating wall to have a smaller heat transfer coefficient at a certain moment,resulting in an increase in the maximum temperature of the wall.This study can provide a reference for the numerical prediction of DNB-type CHF under rolling conditions.
Departure from nucleate boiling(DNB)Critical heat flux(CHF)Rolling conditionNumerical study
万方数据
维普
