管束式换热器导流结构数值模拟研究与优化设计

Numerical simulation and optimization design of diversion structure in tube-type heat exchanger

采用计算流体力学方法,建立进口带导流结构的叉排管束式换热器的CFD模型,分别模拟了换热器入口流速为15、30、46m/s时,导流结构及叉排管束间的流场分布。以前4排管束间截面的速度标准差为流场均匀性判断依据,研究换热器入口变径长度以及内导流结构进出口尺寸对换热器内部流场均匀性的影响.结果表明:在模拟范围内,随着换热器入口流速减小,热器入口变径长度系数λ最优值减小,导流入口结构比值H1/Wi最优值增加,导流出口结构比值H2/H0最优值减小。

A CFD model of tube-type heat exchanger with diversion structure is constructed by using computational flu.id dynamics method.The flow field distributions between the diversion structure and staggered tube bundles have been simulated when the heat exchanger inlet flow rate are 15,30 and 46 m/s.The velocity standard deviation among the first four rows of tube bundles is the criteria for the flow field uniformity.The effects of the heat exchanger inlet length and the inlet and outlet size of the inner diversion structure on the flow field uniformity in the heat exchanger are studied.The re.sults in the simulation condition show that when the inlet flow velocity decreases,the optimal length factor of inlet reduc.er decreases,the optimal ratio of the diversion structure inlet size to the heat exchanger inlet size increases and the opti.mal ratio of the diversion structure outlet size to the heat exchanger body size decreases.