CIESC Journal ›› 2021, Vol. 72 ›› Issue (2): 921-927.DOI: 10.11949/0438-1157.20200640

• Fluid dynamics and transport phenomena • Previous Articles     Next Articles

Investigation of secondary flow in helical coils based on residence time distribution

HUANG Zhengliang1,3(),WANG Chao1,3,GUO Yanni1,3,YANG Yao1,3(),SUN Jingyuan1,3,WANG Jingdai1,2,3,YANG Yongrong1,2,3   

  1. 1.College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, Zhejiang, China
    2.State Key Laboratory of Chemical Engineering, Zhejiang University, Hangzhou 310027, Zhejiang, China
    3.Zhejiang Provincial Key Laboratory of Advanced Chemical Engineering Manufacture Technology, Hangzhou 310027, Zhejiang, China
  • Received:2020-07-25 Revised:2020-09-01 Online:2021-02-05 Published:2021-02-05
  • Contact: YANG Yao

基于停留时间分布的缠绕管内二次流研究

黄正梁1,3(),王超1,3,郭燕妮1,3,杨遥1,3(),孙婧元1,3,王靖岱1,2,3,阳永荣1,2,3   

  1. 1.浙江大学化学工程与生物工程学院,浙江 杭州 310027
    2.浙江大学化学工程联合国家重点实验室,浙江 杭州 310027
    3.浙江省化工高效制造技术重点实验室,浙江 杭州 310027
  • 通讯作者: 杨遥
  • 作者简介:黄正梁(1982—),男,助理研究员,huangzhengl@zju.edu.cn
  • 基金资助:
    国家杰出青年科学基金项目(21525627);国家自然科学基金创新研究群体项目(61621002);国家自然科学基金项目(91834303)

Abstract:

The existence of secondary flow in the helical coil can significantly enhance the mass and heat transfer performance. In this work, based on the residence time distribution of the liquid, the dimensionless variance (σ2) was obtained to characterize the strength of the secondary flow in helical coils. Furthermore,the influence of structural parameters such as the coiling diameter, tube diameter and coiling angle, on the secondary flow in the helical coil was also revealed by this method. The results showed that when the migration distance of radial flow had not reached its limitation in helical coils, σ2 decreased first and then increased with the increase of Reynolds number (Re) of the liquid, corresponding to theturbulent flow action zone and secondary flow action zone. While the migration distance of radial flow had reached its limitation, σ2 decreased first, then increased and finally changed to be steady with the increase of Re of the liquid, corresponding to the turbulent flow action zone, secondary flow action zone and secondary flow limit zone. The critical Reynolds number ReS that changes from the turbulent area to the secondary flow area decreases with the decrease of the winding diameter and pipe diameter of the winding pipe, and the winding angle has little effect on ReS.

Key words: helical coil, residence time distribution, secondary flow, experimental characterization, measurement, fluid mechanics, heat transfer

摘要:

缠绕管内二次流能够显著强化管内传质、传热性能。通过测量缠绕管内液体的停留时间分布,利用无量纲方差σ2表征二次流强度,研究了缠绕直径、缠绕角度、缠绕管管径等结构参数对二次流的影响。结果表明:在径向流动未达到极限迁移距离的缠绕管中,随着液体Reynolds数Re的增大,σ2先减小后增大,对应缠绕管内依次出现的湍流作用区和二次流作用区;在径向流动达到极限迁移距离的缠绕管中,随着Re的增大,σ2先减小后增大最后趋于平稳,对应缠绕管内依次出现的湍流作用区、二次流作用区和二次流极限区。从湍流作用区转变为二次流作用区的临界Reynolds数ReS随缠绕管缠绕直径和管径的减小而减小,缠绕角度对ReS的影响较小。

关键词: 缠绕管, 停留时间分布, 二次流, 实验表征, 测量, 流体力学, 传热

CLC Number: