【摘要】 传统弓形折流板换热器在折流板背流侧存在“流动死区”,会减小壳程传热效率。为降低“流动死区”的影响，提出小孔混流折流板结构，并建立小孔型混流折流板换热器有限元模型，研究小孔位置和数量对换热器壳程传热性能的影响。结果发现，壳程流体在折流板小孔处会形成射流，增强了附近流体的湍流程度，减小了“流动死区”的范围，提高了壳程传热效率。在研究范围内，随着折流板小孔位置向缺口处移动，壳程强化传热能力先增强、后减少。壳程强化传热能力最强的小孔位置靠近折流板缺口，相比没有小孔的传统折流板换热器，此时的努塞尔数提高了17.02%,压力降减少了3.58%。同时还发现，折流板小孔数目越多，虽然壳程流体的流动阻力越小，但换热效率变化不是单调的，意味着折流板的小孔布孔方案存在优化设计空间。更多还原

【Abstract】 There exists a “flow dead zone” on the leeward side of traditional heat exchanger with segmental baffles, which will reduce the shell-side heat transfer efficiency.In order to alleviate the effects of the “flow dead zone”,a so-called small-hole mixed-flow baffle structure was proposed, and finite element models for the heat exchangers with small-hole mixed-flow baffles were established to find out the effects of position and number of the small holes on the shell-side heat transfer performances of the heat exchangers.Results show that the shell-side fluid will form the jet-flow at the position of the small holes, thus enhancing the degree of turbulence of adjacent fluid, reducing the range of “flow dead zone” and improving shell-side heat transfer efficiency.Within the research scope, as the position of the small holes moves towards the window of the baffles, the shell-side heat transfer enhancement capability generally increases first then decreases.The position of the small holes with strongest shell-side heat transfer enhancement capability is close to the window of the segmental baffles, compared to the conventional baffle heat exchanger without small holes, the Nusselt number is increased by 17.02%,whereas the pressure drop is decreased by 3.58%.In addition, it is found that with the increase of the number of the small holes, the shell-side flow resistance also deceases, but the heat transfer efficiency does not change monotonously.Therefore, there is still a room for optimization design of the heat exchangers with small-hole mixed-flow baffles.更多还原