Single-phase and two-phase frictional characteristics of small U-type wavy tubes

I. Y. Chen*, J. C. Huang, Chi-Chuan Wang

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

15 Scopus citations


This study presents single-phase and two-phase frictional characteristics inside small diameter wavy tubes. A total of twelve tubes was used for testing. The ranges for the geometric parameters of the tested wavy tubes are diameter D = 3.43 - 8.29 mm, curvature ratio 2R/D = 3.70 - 7.87, and the ratio of the spacer length L/D = 1.93 - 30.5. For single-phase flow, the bend friction factor increases with the decrease of curvature ratio and spacer length. A friction factor equation is developed based on the experimental data with characterizing parameters like 2R/D, L/D, new Dean number, and Reynolds number. A fair agreement of the fC data and the predictions with a mean deviation of 10.07 % is observed. The frictional two-phase multiplier in U bend can be correlated by using the Chisholm correlation. By introducing the Martinelli parameter and the liquid Froude number to the Chisholm correlation, a new correlation is proposed than can describe the frictional multiplier data, with a mean deviation of 15.86% based on the preset 574 data and the authors' previously reported 279 data.

Original languageEnglish
Pages (from-to)303-314
Number of pages12
JournalInternational Communications in Heat and Mass Transfer
Issue number3
StatePublished - 1 Apr 2004

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