Chuwattanakul, Varesa

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Preferred name
Chuwattanakul, Varesa
Alternative Name
Chuwattanakul, V.
Main Affiliation
Email
varesa.ch@kmitl.ac.th

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    Investigation of turbulent thermal-hydraulic behaviors of a heat exchanger tube with U-cut twisted-tape
    (2025-03-01)
    Wongcharee, K.
    ;
    Chuwattanakul, V.
    ;
    Chamoli, S.
    ;
    Maruyama, N.
    ;
    Hirota, M.
    This study examines the influences of U-cut twisted tapes (U-TTs) on thermal-hydraulic behaviors in a circular tube with uniform heat flux. The geometric parameters studied include six U-cut ratios (s/t = 0.5, 1.0, 1.5, 2.0, 2.5, and 3.0) and two twist ratios (y/w = 3.5 and 4.0). Experimental results revealed that their U-cut ratios highly influenced heat transfer enhancement. U-TTs with U-cut ratios (s/t) of 0.5, 1.0, 1.5, and 2.0 achieved higher Nusselt numbers than conventional twisted tapes (TTs). In contrast, U-TTs with larger U-cut ratios (s/t = 2.5 and 3.0) showed reduced Nusselt numbers. However, friction losses with all U-TTs were consistently higher than those with TTs. Due to their excellent heat transfer enhancement, U-TTs with s/t ratios of 0.5 and 1.0 exhibited significantly higher thermal performance factors (TPF) than conventional TTs. The highest TPF, 1.28, was achieved by U-TTs with an s/t ratio of 0.5 and a y/w of 3.5 at a Reynolds number of 6000.
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    Influence of co/counter arrangements of multiple twisted-tape bundles on heat transfer intensification
    (2021-03-01)
    Eiamsa-ard, S.
    ;
    Changcharoen, W.
    ;
    Beigzadeh, R.
    ;
    Eiamsa-ard, P.
    ;
    Wongcharee, K.
    Heat transfer intensification in tubes containing multiple twisted-tape bundle inserts was experimentally investigated. The experimental parameters included the tape numbers (N) of 2, 4 and 6 pieces, tape twist ratios (y/w) of 4.0, 5.0 and 6.0) and two different tape arrangements: co-swirl tapes (CoT) and counter-swirl tapes (CT). The tests were carried out using air as the working fluid under a constant heat flux. The experimental results showed that all multiple twisted tape bundles caused higher heat transfer rates, pressure losses and thermal hydraulic performance than a typical twisted tape. The heat transfer rate (Nu) and friction factor (f) increased with the number of tapes (N) and decreased with the twist ratio (y/w). At similar operating conditions, the counter-swirl flow twisted tape sets (CT) provided higher heat transfer (Nu) and friction factors (f) than the co-swirl flow sets (CoT). The highest thermal hydraulic performance (η) of 1.33, was offered by the twisted tapes having y/w = 4.0 and N = 6 at Re = 6000.
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    Heat transfer in turbulent tube flow inserted with loose-fit multi-channel twisted tapes as swirl generators
    (2017-11-01)
    Kunlabud, Suttisak
    ;
    Chuwattanakul, Varesa
    ;
    Kongkaitpaiboon, Vichan
    ;
    Promthaisong, Pitak
    ;
    Eiamsa-ard, Smith
    Heat transfer and flow behaviors in three-dimensional circular tubes with loose-fit multiple channel twisted tapes were numerically studied. The investigation was examined for Reynolds numbers (Re) ranging from 5000 to 15,000, by using air as testing fluid. Effects of the multiple channel number (N=2,3, and 4), clearance ratio (CR=0.0, 0.025, 0.05, and 0.075) on heat transfer enhancement and flow friction were examined. The numerical results indicate that the tubes with loose-fit multiple channel twisted tapes perform higher heat transfer rates than the plain tube. The enhanced heat transfer rate is escorted with larger pressure drop. Both heat transfer and pressure drop increase with increasing multiple channel number (N) and decreasing clearance ratio (CR). Heat transfer augmented by the loose-fit multiple channel twisted tape with N=4 is higher than those enhanced by the ones with N=2 and 3 by around 9.5–17.8% and 5.8–7.8%, respectively. In addition, the loose-fit multiple channel twisted tapes with clearance ratio of 0.025, 0.05, and 0.075 give lower heat transfer rates than the one with CR=0.0 by around 8.4%, 17.5%, and 28.8%, respectively.