【摘要】 印刷板式换热器是一种新型高效紧凑式微型通道热交换器,具有紧凑、耐高温、高压的优点,在太阳能、液化天然气和核能等清洁能源领域受到广泛地关注与重视。针对印刷板式换热器应用于LNG行业的汽化器,采用超临界氮气作为工作流体。利用数值模拟和理论分析的方法研究PCHE不同流道弯曲角度、不同直径下进口截面温度变化对内部流动与传热效率的影响。结果表明,弯曲角度增大时,所对应的对流换热系数的数值也随着增大,压降也随之升高;流道直径的加大不仅使对流换热系数增强,压降也随之减小,有较好的传热效果。更多还原

【Abstract】 Printed circuit heat exchanger(PCHE)is a new type of micro-channel heat exchanger with the advantages of being highly efficient and compact,which is widely studied in the clean energy fields,such as solar energy,nuclear energy and liquefied nature gas.Nowadays many scholars at home and abroad have focused on how to improve the heat transfer capacity and efficiency of PCHE.The heat transfer mechanism inside the internal micro-channels of PCHE is complicated,which needs to be further investigated.In this paper,the method of numerical simulation and theoretical analysis is applied to study the influence of the inlet temperature variations on the flow and heat transfer efficiency of PCHE under different flow channel bending angles and different semicircular diameters,using the supercritical nitrogen as the working fluid.The numerical results indicate that both the convective heat transfer coefficient and the pressure drop are increased when the bending angle is increased.When the diameter of the flow channel is increased,the convective heat transfer coefficient is correspondingly increased and the pressure drop is decreased.更多还原