Host: The Japan Society of Mechanical Engineers
Name : International Conference on Power Engineering-2021(ICOPE-2021)
Date : October 17, 2021 - October 21, 2021
Secondary flow effect was brought by the U-bend in the heat exchange system. Under the effect of secondary flow, bubble behavior in subcooled boiling is more complicated, the flow process is obviously different from that of the straight pipe. It is crucial to investigate the influence of the U-bend on the two-phase heat transfer characteristics for the accurate prediction and design of the boiling heat transfer in the tube. Present work shows that: U-bend have a significant effect on distribution of mean void fraction and wall temperature. For onset of fully developed boiling, the bend with smaller curvature has less effect. The result of mean void fraction is under the combined effect of secondary flow and increase effect of onset of fully developed boiling. For the critical heat flux of U-tube, when position of bend is near the deterioration position of straight pipe, bend aggravated the deterioration, wall temperature increased more obvious. Also results show that and the critical heat flux in the U-tube is lower than that of the straight pipe.
