顺排管束作为换热器的关键换热结构,本文针对三行四列顺排管束,采用大涡模拟数值研究雷诺数5500工况下的脉动流强化传热方法应用于顺排管束。首先分析稳态流工况管束间存在的涡脱落现象和剪切层不稳定性,获取涡脱落频率fvs和剪切层不稳定频率fsl,选定涡脱落频率fvs数值作为脉动流的强迫频率fp。随后在相同工况施加脉动流,进一步分析脉动流对管束的流动传热的影响,最后提出脉动流强化传热的深层机制。结果显示,脉动流脉动流对于中间管束的强化作用相比于第1列和最后1列更加明显,相比于稳态流,脉动流使管束的时均努塞尔数和压力系数和综合传热系数PEC都有提高。

Sequential bundle is the key heat transfer structure of heat exchanger. In this paper, three rows and four rows of sequential bundle are studied by using large eddy simulation to apply pulsating flow heat transfer enhancement method to sequential bundle at Reynolds number 5500. Firstly, the vortex shedding phenomenon and shear layer instability between bundles in steady-state flow conditions were analyzed, and the vortex shedding frequency fvs and shear layer instability frequency fsl were obtained. The value of vortex shedding frequency fvs was selected as the forcing frequency fp of pulsating flow. Then the pulsating flow is applied in the same working condition to further analyze the influence of pulsating flow on the flow heat transfer of the bundle, and finally put forward the deep mechanism of pulsating flow to strengthen the heat transfer. The results show that the pulsating flow has a more obvious strengthening effect on the middle bundle compared with the first and last column. Compared with the steady-state flow, the pulsating flow increases the Nusselt number, pressure coefficient and comprehensive heat transfer coefficient PEC of the bundle.