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针对现有平面螺旋折流板换热器的相邻折流板与壳体间存在的三角漏流区,提出了一种折面螺旋折流板换热器。本文基于实验研究分析了折面螺旋折流板换热器的螺旋角和搭接度对流动传热性能的影响,并拟合了壳程对流传热和阻力系数的实验关联式。结果表明,当壳程体积流量相同时,随着螺旋角的减小,折面螺旋折流板换热器的壳程总压降增加,壳程管束压降增加,壳程膜传热系数提升,综合性能增强;相同壳程体积流量下,随着搭接度的增加,壳程总压降也增加,壳程膜传热系数增加,综合性能提高。实验研究表明螺旋角18°,搭接度50%的折面螺旋折流板换热器流动传热性能最佳。首次将折面螺旋折流板换热器的螺旋角和搭接度作为修正因子拟合到了实验关联式中,对比发现实验值与Nu实验关联式计算值的平均相对误差为1.13%,与f实验关联式的平均相对误差为6.84%,说明了拟合的正确性和可靠性。本文研究结果为折面螺旋折流板换热器的设计提供了理论指导。
Aiming at the triangular leakage area existing between the adjacent baffles and the shell of the existing planar spiral baffle heat exchanger, a spiral baffle heat exchanger with a spiral face is proposed. Based on the experimental study, the effects of helix angle and lap degree on flow and heat transfer performance of the folded spiral baffle heat exchanger were analyzed and the experimental correlation between convection heat transfer and drag coefficient in the shell side was fitted. The results show that with the decrease of helix angle, the total pressure drop in the shell-side spiral baffle heat exchanger increases, the pressure drop in the shell side tube bundle increases, and the heat transfer coefficient of the shell side membrane increases , The overall performance is enhanced. Under the same shell-side flow rate, the total pressure drop in the shell side increases with the increase of the degree of overlap, and the heat transfer coefficient of the shell side shell increases. The overall performance increases. Experimental studies show that the helical angle 18 °, degree of overlap 50% of the spiral baffle heat exchanger heat transfer performance is best. For the first time, the helix angle and the degree of overlap of the spiral helix baffle heat exchanger were fitted to the experimental correlation as a correction factor. The average relative error between the experimental value and the Nu experimental correlation calculation was found to be 1.13% The average relative error of experimental correlation is 6.84%, which shows the correctness and reliability of fitting. The results of this paper provide theoretical guidance for the design of the faceted spiral baffle heat exchanger.