波壁管式换热器内壳侧流体流动与换热特性

Fluid Flow and Heat Transfer Characteristics of Inner Shell-side of a Wave Wall Tube Heat Exchanger

传统的直壁管式换热器的换热效率不高,为了增强换热器内流体的换热效率。采用数值模拟的方法对<1-2>型波壁管式换热器内流体的流动与换热特性进行了研究,重点探讨了雷诺数Re与波壁管半径比i对换热器内流体的流动特性、阻力特性、换热特性以及综合换热性能的影响。结果发现,与直壁管式换热器相比,波壁管式换热器内流体的流动状态能够得到较大的改善。波壁管式换热器壳程流体的进出口平均压降比直壁管式换热器低,平均压降最大可降低11.01%,并且发现随着Re的增加,平均压降明显增大,随着i的增加,平均压降略有增大。波壁管式换热器壳程内流体的对流换热系数h明显大于直壁管式换热器,h最大可增加14.17%。h随着Re的增大逐渐增加,而i对h的影响不明显。同时发现波壁管式换热器的综合换热性能与雷诺数Re成正相关,而与半径比i成负相关。与直壁管式换热器相比,波壁管式换热器的综合换热性能更强。

The heat exchange efficiency of the traditional straight wall tube heat exchanger is not high, in order to enhance the heat exchange efficiency of the fluid in the heat exchanger. The flow and heat transfer characteristics of fluid in <1-2> wave wall tube heat exchanger were analyzed and studied by numerical simulation. The effects of Reynolds number Re and wave wall tube radius ratio i on the flow characteristics, resistance characteristics, heat transfer characteristics and comprehensive heat transfer performance of fluid in the heat exchanger were discussed. The results show that compared with the straight wall tube heat exchanger, the fluid flow state in the wave wall tube heat exchanger can be greatly improved. The average pressure drop at the inlet and outlet of the shell-side fluid of the wave wall tube heat exchanger is lower than that of the straight wall tube heat exchanger, and the maximum average pressure drop can be reduced by 11.01%. It is found that the average pressure drop increased significantly with the increase of Re, and increases slightly with the increase of i. The convective heat transfer coefficient hof the fluid in the shell side of the wave wall tube heat exchanger is significantly higher than that of the straight wall tube heat exchanger, and hcan be increased by 14.17% at most. The hgradually increased with the increase of Re, but the effect of i on his not obvious. At the same time, it is found that the comprehensive heat transfer performance of a wave wall tube heat exchanger is positively correlated with Reynolds number Re and negatively correlated with radius ratio i. Compared with the straight wall tube heat exchanger, the wave wall tube heat exchanger had stronger comprehensive heat transfer performance.