多通道烘缸结构参数对烘缸传热性能的影响

Study on the Influence of Structural Parameters of Multi-channel Cylinder Dryer on Heat Transfer Performance

提出了多通道烘缸内部结构的设计方法,分析了多通道烘缸结构参数对蒸汽冷凝传热及流动特性的影响。首先指出通道数量、高宽比和间隔比等参数与通道宽度、高度和当量直径等结构参数的关系,然后引入Cavallini冷凝传热系数实验关联式及均相流模型,分析了结构参数对多通道烘缸蒸汽冷凝传热系数和沿程阻力的影响。结果表明,通道数量、高宽比和间隔比对蒸汽冷凝传热系数及沿程阻力的影响较大。综合分析结果表明,当通道数量为150~200、高宽比为1∶3及间隔比为1∶1~1∶3时,多通道烘缸的整体性能最好。

An approach to design a multi-channel cylinder dryer was proposed. The heat transfer performance and flow characteristic with va- rious structural parameters were analyzed. The relationship among the number of channels, aspect ratio, spacing ratio, width, height and hy- draulic diameter of a channel was firstly given, then the Cavallini condensing heat transfer coefficient experiment corelation formula and the homogeneous phase flow model were introduced in order to analyze the heat transfer performance and flow characteristic of the multi-channel cylinder dryer affected by different structural parameters. The study revealed that the structural parameters including number of channels, as- pect ratio, spacing ratio of a channel dramatically influenced the condensation heat transfer coefficient and frictional resistance of the steam. Based on the selected paper machine, it was suggested that the overall performance of the multi-channel cylinder dryer was the best if the number of channels was 150 ～ 200, its aspect ratio and spacing ratio was 1：3 and 1 ： 1 ～ 1 ： 3 respectively.