Heat Transfer Enhancement in a Round Tube Using a Wire Coil. The Influences of the Length and the Segmentation.

Shoji, Yukitsugu; Sato, Kyozo; Oliver, Dana

doi:10.1252/kakoronbunshu.24.573

Cited by 1 publication

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“…In regard to wire coil inserts, there are recent reports by Inaba and colleagues [1,2] and Shoji and colleagues [3,4] dealing with the heat transfer coefficient and the flow resistance in the transition region from laminar flow to turbulent flow for single-phase flows. An experimental investigation of the occurrence of critical heat flux in subcooled flow boiling of water has been carried out by Celata and colleagues [5] who found that use of turbulence promoters in a tube with a wire coil is an effective method for subcooled flow boiling critical heat flux.…”

Section: Introductionmentioning

confidence: 99%

The flow characteristics of an upward gas‐liquid two‐phase flow in a vertical tube with a wire coil: Part 2. Effect on void fraction and liquid film thickness

Takeshima

Fujii

Takenaka

et al. 2002

Heat Trans. Asian Res.

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An experimental study has been carried out to clarify the characteristics of the void fraction and the liquid film thickness of the air‐water two‐phase flow in vertical tubes of 25‐mm inside diameter with wire coils of varying wire diameter and pitch. The flow pattern in the experiment on the average void fraction and the local void fraction distribution in cross section was a bubble flow, and the liquid film thickness was in the region of semiannular and annular flows. It is clarified from these experiments that the average void fraction in tubes with wire coils is lower than that in a smooth tube and decreases with the wire diameter owing to the centrifugal force of the swirl flow which concentrates bubbles at the center of the tube, that the local liquid film thickness becomes more uniform with a decrease in the pitch of the wire coil, and that the liquid film becomes thicker after the passage through the wire coil with an increase in the wire diameter. © 2002 Wiley Periodicals, Inc. Heat Trans Asian Res, 31(8): 652–664, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.10067

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