Promvonge, Pongjet
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Preferred name
Promvonge, Pongjet
Alternative Name
Promvonge, P.
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pongjet.pr@kmitl.ac.th
33 results
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Item type:Publication, Thermo-hydraulic performance in heat exchanger tube with V-shaped winglet vortex generator(2020-01-05); Skullong, SompolThis article presents the influence of V-shaped winglet vortex generators (V-WVGs) inserted into a constant heat-fluxed tube on thermal characteristics. In the present experiment, two V-WVG types: V-shaped rectangular- and delta-winglets (V-RW and V-DW) were mounted periodically on both sides of a straight tape before insertion into the tube with four relative winglet pitches (P<inf>R</inf> = P/D = 0.5, 1.0, 1.5 and 2.0) and three winglet blockage ratios (B<inf>R</inf> = b/D = 0.1, 0.15 and 0.2) at a fixed attack angle (α = 45°). Effects of geometric parameters of both V-WVGs on thermal performance enhancement were studied using air as tested fluid in a turbulence condition, Reynolds number (Re) ranging between 4130 and 25,900. The measured result has been shown that the V-RW performs higher rate of heat transfer as well as friction loss than the V-DW and the rise in B<inf>R</inf> results in higher increase of the heat transfer rate and friction loss while the increment in P<inf>R</inf> yields the reversing tendency for both V-WVG types. A new thermal-performance enhancement factor (TEF) has been introduced and it reveals that the V-DW has TEF in a range of 1.82–2.0 or around 3% above the V-RW where its peak regarded as the optimal point is at B<inf>R</inf> = 0.15 and P<inf>R</inf> = 1.0. Empirical correlations for the Nusselt number and friction factor to assess the real merits of a heat exchanger tube with V-WVGs are determined. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Analysis of exergy and heat transfer in a tube fitted with flapped V-baffles(2024-07-01); ; - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Entropy generation and thermal performance of tubular heat exchanger fitted with louvered corner-curved V-baffles(2023-02-01); ; ; Skullong, SompolThe current article deals with an experimental study on entropy generation analysis and thermohydraulic performance of a uniform heat-flux tube equipped with louvered corner-curved baffle tape (LCBT). Air was drawn into the inserted tube for the Reynolds number (Re) between 4760 and 29,300. The V-shaped LCBT arranged by V-tip in downstream direction was introduced with three baffle pitch ratios (P<inf>R</inf> = 1–2) and six louver angles (θ = 0–90°) for a fixed attack angle (α) of 30° and baffle height ratio (B<inf>R</inf> = 0.25). The impacts of investigated parameters on the thermal enhancement factor (TEF), Nusselt number (Nu), friction factor (f), and total entropy generation (S˙<inf>gen</inf><sup>′</sup>) were examined. The measurements showed that the LCBT with the smallest values of P<inf>R</inf> = 1, θ = 0° give the largest Nu and f at about 4.4 and 19.2 times above the plain tube values, respectively. However, the greatest TEF around 2.23 was seen for employing the LCBT at P<inf>R</inf> = 1, θ = 45°. The entropy analysis also showed that the S˙<inf>gen</inf><sup>′</sup> is found to decline with the increment of P<inf>R</inf> and θ, whereas the minimal S˙<inf>gen</inf><sup>′</sup>is at P<inf>R</inf> = 1, θ = 0° for lower Re but at P<inf>R</inf> = 1, θ = 45° for higher Re. Furthermore, the Nu and f empirical correlations for employing LCBTs were also proposed. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Thermal performance of heat exchanger tube inserted with curved-winglet tapes(2018-01-25); ; ; The paper deals with the effect of curved-winglet (CW) inserts on thermal and flow behaviors in a constant heat-fluxed tube. A straight tape is used to support the 45° CWs mounted repeatedly on both tape sides to generate two pairs of longitudinal counter-rotating vortices along the test tube in order to assist the chaotic flow mixing and to disrupt the boundary layer leading to faster rate of heat transfer. The airflow and heat transfer behaviors in the tube are examined for Reynolds number (Re) in the range of 4150–25,400. The curved-winglet tape (CWT) parameters involved are the winglet attack angle of 45° three relative winglet heights (b/D = B<inf>R</inf> = 0.1, 0.2 and 0.3) and winglet pitches, (P/D = P<inf>R</inf> = 0.5, 1.0 and 2.0). The investigation reveals that the maximum thermal enhancement factor (TEF) of the CWT is about 1.62 at B<inf>R</inf> = 0.1 and P<inf>R</inf> = 1.0. For further improvement, the CWT at B<inf>R</inf> = 0.1 and P<inf>R</inf> = 1.0 is modified by punching the CW to be the perforated-curved-winglet tape (P-CWT) to reduce the pressure loss. The P-CWT characteristics include five different punched hole diameters (d = 1.0, 1.5, 2.0, 2.5 and 3.0 mm). The experimental results show that TEF of all the P-CWTs is higher than that of the CWT and the maximum TEF of 1.76 higher than the CWT around 9% is found for d = 1.5 mm. To understand the flow pattern and heat transfer mechanism, a three-dimensional CFD investigation is also performed and for validation, the good agreement between numerical and experimental results is found. For experimental data, empirical correlations for Nu, f and TEF for the CWT and P-CWT inserts are also determined. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Thermohydraulic performance and entropy generation in heat exchanger tube with louvered winglet tapes(2022-11-01); Skullong, SompolThe present article concerns with thermohydraulic performance, flow friction and entropy generation analysis in a heated tube contained with louvered winglet tape (LWT). The experiment was conducted in a uniform heat-fluxed test tube for turbulent fluid flow, Reynolds number (Re) ranging from 4760 to 29,260. The purpose of the LWT insert is to produce streamwise vortices assisting to induce impinging-jets onto the tube wall and to decline the pressure loss through the louver mounted on the winglet aside from providing rapid mixing of fluid flow. In the present experiment, the louvered winglets were mounted periodically on a double-sided straight tape with six different louver angles (θ = 0 ˗ 90°) and three winglet pitch ratios (P<inf>R</inf> = 1 ˗ 2) at a single relative winglet height (B<inf>R</inf> = 0.25) and a fixed attack angle (α) of 30°. There were two-types of LWT arrangements: inline and staggered louvered-winglet tapes (I-LWT and S-LWT). To examine the optimum thermohydraulic performance, an influence of θ at each P<inf>R</inf> on the rate of heat transfer and friction loss inside the tube was explored. The measured results disclosed that the Nusselt number (Nu) and friction factor (f) from using both types of LWTs rise considerably with the reduction of P<inf>R</inf> and θ. The entropy generation (S˙<inf>gen</inf><sup>'</sup>) was declined with the decrease in Re, P<inf>R</inf> and θ where the minimum S˙<inf>gen</inf><sup>'</sup> was obtained for the I-LWT tube at P<inf>R</inf> = 1, θ = 0° and lowest Re. The peak thermal enhancement factors (TEF) of the S-LWT and the I-LWT were, respectively, around 2.22 and 2.18 at similar P<inf>R</inf> = 1, θ = 45°. The Nu, f and TEF correlations for using LWT insert were also reported. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Enhanced thermal effectiveness of square duct with V-type double-baffles: Numerical study(2024-09-01); ; - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Enhanced thermal performance in tubular heat exchanger contained with V-shaped baffles(2021-02-25); Skullong, SompolThe vortex-flow device is a promising streamwise vortex generator employed to produce the counter-rotating vortices along a heated tube to augment the heat transfer rate with comparatively smaller friction loss penalty. Thus, the influences of V-shaped baffle vortex generator (hereafter called “V-baffle”) insert in a heated tube on thermal-performance enhancement were experimentally examined in the current work. The geometric characteristics of the V-baffles mounted repeatedly on the edges of a flat plate/tape were three ratios of relative baffle blockages, (b/D = B<inf>R</inf> = 0.1, 0.15 and 0.2), and four ratios of baffle pitches, (P/D = P<inf>R</inf> = 0.5, 1.0, 1.5 and 2.0) at a fixed angle of attack (α = 30°). The present V-baffle placed on the tape edge was aimed to lessen the pressure loss from disturbing the central core flow for the case of placing it on the double sides of a tape as found in the literature. The experiment was conducted by letting air flow through the test tube with Reynolds number (Re) in the range of 4192 to 25,750. The current study indicated that the friction factor and heat transfer using the V-baffle inserts increase considerably with rising B<inf>R</inf> but reducing P<inf>R</inf>. The V-baffle with B<inf>R</inf> = 0.2, P<inf>R</inf> = 0.5 provides the highest friction factor and rate of heat transfer at about 18.25 and 4.46 times above the plain tube, respectively. A new modified thermal enhancement factor (TEF) is offered and found that its peak for each case appearing at the lowest Re, is in a range of 2.14–2.34 where the optimum TEF of 2.34 is visible at P<inf>R</inf> = 1.0, B<inf>R</inf> = 0.15. Furthermore, correlations of Nusselt number and friction factor for the present V-baffles are determined. TEF of the current device is found to be superior to that of other enhanced devices in comparison. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Enhancement of heat transfer in a tube with regularly-spaced helical tape swirl generators(2005-01-01) - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Enhanced heat transfer in rectangular duct with punched winglets(2020-03-01); Skullong, SompolThermal performance of a heat exchanger duct with punched winglets (PWs) mounted on the upper duct wall has been examined for Reynolds number (Re) ranging from 4100 to 25,500. In the present experiment, two types of PWs: punched delta- and elliptical-winglets (P-DW and P-EW) with four punched-hole sizes were tested at a fixed attack angle, optimal relative pitch and height. Also, data of solid delta- and elliptical-winglets (DW and EW) were included for comparison. The investigation has shown that the P-DW yields higher thermal-performance enhancement factor (η) than the P-EW. Although the solid DW and EW with no punch have the highest heat transfer and friction loss, the PWs yield better η than the solid ones. For PWs, the P-DW with smaller hole size has the peak heat transfer and friction loss around 5.7 and 40 times over the smooth duct, respectively but the optimum η of 2.17 is seen for the one with a certain hole size. The PWs provide η at about 5%–8% above the solid winglets. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Turbulent heat transfer enhancement in a heat exchanger using helically corrugated tube(2011-03-01); The augmentation of convective heat transfer in a single-phase turbulent flow by using helically corrugated tubes has been experimentally investigated. Effects of pitch-to-diameter ratio (P/D<inf>H</inf>=0.18, 0.22 and 0.27) and rib-height to diameter ratio (e/D<inf>H</inf>=0.02, 0.04 and 0.06) of helically corrugated tubes on the heat transfer enhancement, isothermal friction and thermal performance factor in a concentric tube heat exchanger are examined. The experiments were conducted over a wide range of turbulent fluid flow of Reynolds number from 5500 to 60,000 by employing water as the test fluid. Experimental results show that the heat transfer and thermal performance of the corrugated tube are considerably increased compared to those of the smooth tube. The mean increase in heat transfer rate is between 123% and 232% at the test range, depending on the rib height/pitch ratios and Reynolds number while the maximum thermal performance is found to be about 2.3 for using the corrugated tube with P/D<inf>H</inf>=0.27 and e/D<inf>H</inf>=0.06 at low Reynolds number. Also, the pressure loss result reveals that the average friction factor of the corrugated tube is in a range between 1.46 and 1.93 times over the smooth tube. In addition, correlations of the Nusselt number, friction factor and thermal performance factor in terms of pitch ratio (P/D<inf>H</inf>), rib-height ratio (e/D<inf>H</inf>), Reynolds number (Re), and Prandtl number (Pr) for the corrugated tube are determined, based on the curve fitting of the experimental data. © 2010 Elsevier Ltd.