Promvonge, Pongjet

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Promvonge, Pongjet
Alternative Name
Promvonge, P.
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pongjet.pr@kmitl.ac.th

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    Enhanced thermal effectiveness of square duct with V-type double-baffles: Numerical study
    (2024-09-01)
    Promvonge, Pongjet
    ;
    Sripattanapipat, Somchai
    ;
    Thianpong, Chinaruk
    ;
    Skullong, Sompol
    ;
    Promthaisong, Pitak
    The article puts forward three-dimensional computational research on heat transmission augmentation within a square channel containing 45<sup>o</sup> V-type double-baffles positioned on the lower and top parts at regular intervals in the turbulence zone for Reynolds numbers (Re) that vary from 3000 to 20,000. The primary goal of this research is to increase the thermal effectiveness and relative Nusselt number (Nu/Nu<inf>0</inf>), in order to conserve energy and reduce the size of the heating or cooling system. The simulations utilize a finite volume approach in common with the SIMPLE algorithm, whereas the turbulent model used is the realizable k–ε. The baffles are designed to be separated vertically for reducing pressure loss. Both single V-baffles and double V-baffles have four relative pitches (PR = 0.4, 0.5, 0.6, and 1.0) and height/blockage ratios (BR = 0.05, 0.1, 0.15, and 0.2), with a fixed attack angle (α) of 45<sup>o</sup>. The computational findings show that both V-baffles are capable of producing the primary vortices, but only the double V-baffles have the ability to provide the impinging streams onto the wall, cooling the region behind the baffles. This suggests that the double V-baffles not only boost heat transmission but also reduce frictional loss. When compared to a single V-baffle, the double ones enhance heat transfer by an average of 1.04–9.94% while decreasing frictional loss by an average of 9.88–31.73%. The thermal effectiveness factor (TEF) of the double V-baffles ranges from 1.03 to 3.21, and its peak value of around 3.21 is for PR = 0.4, BR = 0.05, at lower Re.
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    Numerical Heat Transfer Investigation in a Heat Exchanger Tube with Hexagonal Conical-ring Inserts
    (2016-11-01)
    Sripattanapipat, Somchai
    ;
    Tamna, Sombat
    ;
    Jayranaiwachira, Nuthvipa
    ;
    Promvonge, Pongjet
    The hexagonal conical rings (HCR) modified from the typical conical ring (CR) are used as a turbulence promoter for producing the vortex flows to enhance the heat transfer rate in a heat exchanger tube. To reduce the pressure loss, the V-shaped HCR (V-HCR) obtained by cutting both symmetric plane of the cone-tip of HCR at 30°, 45°and 60°is offered in the present work. The tube fitted with V-HCR elements having a fixed inlet and outlet diameter is numerically investigated. The computation is carried out for Reynolds number in a range of 3000 to 20,000 in a uniform heat-fluxed test tube. The numerical results show that the V-HCR insert leads to much higher heat transfer than the typical CR/HCR insert or the smooth tube alone and also provides lower friction factor. The 30°V-shaped HCR gives the highest heat transfer and thermal performance due to the lowest friction loss, indicating the promising device of the V-HCR.
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    Experimental and numerical evaluations of thermal performance in heat exchange channel with punched V-type delta-winglets
    (2026-09-01)
    Promthaisong, Pitak
    ;
    Sripattanapipat, Somchai
    ;
    Suchatawat, Maturose
    ;
    Nakhchi, Mahdi Erfanian
    ;
    Promvonge, Pongjet
    An experimental examination on the heat transmission improvement of a heat exchange channel (HXC) with punched V-shaped delta-winglets (PVDWs) positioned at regular intervals along the heated wall is presented in the article. This channel has a consistent heat flux for the fluid flow with a Reynolds number (Re) between 5295 and 22,700. By producing vortex flows, the PVDWs help to mix the airflow more rapidly, decrease friction loss via the winglets' louver flap, and direct air jets onto the hot-plate wall. PVDWs with three relative pitches (P<inf>R</inf> = 1, 1.5, and 2) and five louver flap angles (θ = 90°, 60°, 45°, 30°, and 0°) were spaced regularly on the heated surface. The relative winglet height (B<inf>R</inf>) was maintained at 0.5 and the attack angle was fixed at 45°. Two types of winglet patterns were in use: inline PVDW and staggered PVDW. Thermal effectiveness factor (TEF), Nusselt number (Nu), and friction factor (f) were all influenced by the PVDW parameters. Varieties of θ and P<inf>R</inf> are examined parametrically. The smallest Reynolds number results in the greatest rise in frictional factor (f<inf>R</inf> = 75.07), while the largest Reynolds number gives the greatest improvement in heat transfer rate (Nu<inf>R</inf> = 7.63) for I-PVDW at θ = 0° and P<inf>R</inf> = 1.0. Both the S-PVDW and the I-PVDW reached their maximum TEFs at θ = 45° and P<inf>R</inf> = 1, with the former reaching 2.67 and the latter 2.63. Nu and f correlations can also be estimated using their measured data. The best thermal effectiveness and lower friction in the test channel are achieved by using S-PVDWs. The predicted findings were validated by the matching measured data after a 3D numerical study was performed to analyze heat transfer and flow patterns using the realizable k-ε turbulence model. Both the experimental and computational results were in good agreement, and the heat transfer mechanism of the PVDW was elucidated. A reconfiguration of the S-PVDW is performed by reversing the flap angle to increase thermal effectiveness. At θ = −45° and P<inf>R</inf> = 1, the updated S-PVDW shows a highest TEF of 2.78, which is approximately 4% better than the previous analysis.
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    Thermal effectiveness augmentation in heated tube with louver-punched delta winglets
    (2025-09-01)
    Promvonge, Pongjet
    ;
    Sripattanapipat, Somchai
    ;
    Promthaisong, Pitak
    ;
    Suchatawat, Maturose
    ;
    Nakhchi, Mahdi Erfanian
    Louver-punched delta winglet (LPDW) vortex generators were presented as a way to increase convective heat transmission in a tubular exchanger. LPDW arrays were categorized as inline or staggered louver-punched delta winglets (I-LPDW and S-LPDW, respectively). Experimental and numerical research was carried out for Reynolds numbers varying from 4760 to 29,290 to analyze the thermal patterns and flow characteristics within a constant heat flux tube with LPDWs. The turbulence model adopted for the present research was the realizable k-ε model. For both I-LPDW and S-LPDW winglet arrangements, a single ratio of blockage (B<inf>R</inf> = e/D = 0.25), pitch ratio (P<inf>R</inf> = P/D = 1), and attack angle (α = 60°) was utilized as well as three ratios of louver length (L<inf>R</inf> = d/e = 0.24–0.56) and five flap angles (θ = 0°–90°). The research showed that when the θ and L<inf>R</inf> values fall, the LPDW's friction factor (f) and Nusselt number (Nu) grow since streamwise vortices that possess greater kinetic energy of turbulence promote fluid mixing. The winglet with θ = 45°, L<inf>R</inf> = 0.24 exhibited a peak TEF of 2.56 for I-LPDW and 2.63 for S-LPDW whereas the winglet with θ or L<inf>R</inf> = 0° had the largest Nu and f values, at 5.41 and 24.38 times, respectively. The numerical results illustrated that both LPDWs produce many longitudinal vortices throughout the tube. These flow patterns improved fluid mixing in the tube by raising the fluid's kinetic energy of turbulence. Additionally, the findings of the verification between the computational and experimental data were satisfactory. The Nu and f correlations for the I-LPDW and S-LPDW were also established using measured data.
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    Numerical Heat Transfer Study of Turbulent Tube Flow through Winglet-pairs
    (2016-11-01)
    Tamna, Sombat
    ;
    Sripattanapipat, Somchai
    ;
    Promvonge, Pongjet
    A numerical investigation on heat transfer behaviors in a constant heat-fluxed round tube inserted with winglet vortex generators is conducted. Air as the working medium flows through the tube for Reynolds numbers (Re) between 4000 and 20,000. The effect of using the rectangular-winglet tape (RWT) on heat transfer characteristics in the tube is numerically examined. For comparison purpose, the trapezoidal-winglet tape (TWT) and delta-winglet tape (DWT) are also offered. The RWT parameters in this work include four relative winglet-to-tube heights or blockage ratios (B<inf>R</inf>=b/D= 0.1, 0.15, 0.2, and 0.25) while the TWT and DWT are only at B<inf>R</inf>= 0.2. All the winglet pairs are at a single attack angle (α= 45°) and pitch ratio (p/D=P<inf>R</inf>=4). The numerical results show that the Nusselt number (Nu) and friction factor (f) of the tube inserts are enhanced with increasing B<inf>R</inf> values. The Nu for the inserted tube is about 1.8-2.7 times above that for the smooth tube while the f is around 4.5-11 times higher. For the studied B<inf>R</inf> ranges, the highest thermal performance is 1.48 for the RWT with B<inf>R</inf>= 0.1 at lower Reynolds number.