Abstract： Based on VOF multiphase model, the critical heat flux(CHF) in narrow rectangular channel was numerically simulated by CFD software. The flow regime transition was analyzed to draw the flow pattern maps. The factors on critical heat flux were summarized， and the results were compared with the experimental facts to verify the simulation reliability. The results show that only bubbly flow, slug flow and annular flow are appeared in the narrow channel, and the growth and the coalescence of bubble are restricted by channel size, which are slightly different with conventional channels. The CHF increases monotonically with the increasing of mass velocity and decreases with the increasing of L/De. The influence of inlet subcooling on CHF can be neglected. The CHF of upflow is slightly larger than that of downflow under the same channel dimension and inlet conditions, and low mass velocities shows great sensitivity to orientation.
2016, Vol. 37 
