旋梯式螺旋折流板换热器换热性能的实验研究

Experimental Investigation on Heat Transfer Performance of Heat Exchanger with Ladder-Type Fold Baffles

目前普遍使用的螺旋平面折流板换热器在相邻两块折流板的直边对接处存在X形的内外两个三角漏流区，严重影响了换热器性能的提高。采用旋梯式折面折流板替代平面折流板后，由于旋梯式折面折流板两侧的折弯面能使相邻两块折流板密切接触，封闭了三角漏流区，改善了壳程流场。实验结果表明，旋梯式螺旋折流板换热器相比于螺旋平面折流板换热器，总传热系数平均增加21．4％，壳侧传热系数平均增加27．3％，而压降增加引起的泵耗功率增量为2~80W。换热器的热性能因子提高了14．8％~24．2％，平均增加19．5％。此外，旋梯式螺旋折流板换热器具有定位和安装简单方便等优点。本研究结果对于换热器的节能优化具有重要的指导意义。

Conventional plain baffles are often used in heat exchangers with helical baffles. There are two X-shaped triangular leakage zones between the two adjacent plain baffles, which decrease heat transfer performance of the heat exchanger obviously. The improved configuration of ladder-type fold baffle was proposed. Folded panels of the two adjacent ladder-type fold baffles contact closely to eliminate the triangular leakage zones and thus the shell-side flow field is improved significantly. The experimental results show that the overall heat transfer coefficient of the improved heat exchanger with ladder-type fold baffles increases by an average value of 21.4% compared with that of conventional heat exchanger with plain baffles. And the shell-side heat transfer coefficient increases by an average value of 27.3%. However, the increment in pumping power penalty due to the increase of shell-side pressure drop is 2-80 W. The thermal performance factor TEF is enhanced by 14.8%-24.2%, with an average value of 19.5%. In addition, heat exchangers with ladder-type fold baffles are convenient in localization and installation. The results of this paper are of great significance in the optimum design of the heat exchanger.