Promvonge, Pongjet

Preferred name

Promvonge, Pongjet

Alternative Name

Promvonge, P.

Main Affiliation

School of Engineering

pongjet.pr@kmitl.ac.th

Now showing 1 - 10 of 15

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Analysis of exergy and heat transfer in a tube fitted with flapped V-baffles
(2024-07-01)
Jayranaiwachira, Nuthvipa
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Promvonge, Pongjet
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Tongyote, Paritkavin
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Skullong, Sompol
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Nakhchi, Mahdi Erfanian
Vortex generator is a device that shows promise in generating streamwise vortices that can be utilized for boosting the rate of heat transmission inside a cooling/heating system with a relatively smaller penalty in terms of friction loss. The primary goal of the current research is to maximize the comparative Nusselt number ratio (Nu/Nu<inf>0</inf>) to be as large as possible to lower the size of the system while keeping thermal performance as high as feasible to save more energy. Thus, in the current study, the impacts of inserting the flapped V-baffle vortex generator (FBVG) on the thermal effectiveness improvement of a round tube were experimentally investigated. At a fixed attack angle (α = 60°) and baffle blockage ratio (B<inf>R</inf> = b/D = 0.3), the geometrical behaviors of FBVGs placed periodically along two edges of a straight tape were six different flap angles (θ = 0°, 25°, 35°, 45°, 65° and 90°) and three ratios of baffle pitches (P/D = P<inf>R</inf> = 2.0, 1.5, and 1.0). The current V-baffles, which were positioned on both tape edges, were designed to reduce friction loss caused by interrupting the central core flow when placed on both tape sides. The measurement results focused on the friction loss and thermal behaviors, including exergy and entropy analyses for Reynolds number from 4750 to 29,270. In the findings, the Nusselt number and friction factor of FBVG at θ = 0° and P<inf>R</inf> = 1 are, respectively, up to 5.6 and 35.24 times larger than those of the smooth tube. The entropy generation (S˙<inf>gen</inf>′) seems to decline as θ and P<inf>R</inf> increase, with the smallest S˙<inf>gen</inf>′ found at θ = 0° and P<inf>R</inf> = 1 for lower Re. The FBVG has the greatest exergy efficiency (η<inf>Ex</inf>) at θ = 0° and P<inf>R</inf> = 1. To find the true benefits of FBVG, its thermal performance is estimated and seen to reach a maximum at about 2.44 with Nu<inf>R</inf> = 4.65 at θ = 45° and P<inf>R</inf> = 1. The optimal scenario at θ = 25° and P<inf>R</inf> = 1 was preferred, however, since it yielded the largest Nu<inf>R</inf> = 5.42 at TEF = 2.39.
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Entropy generation and thermal performance of tubular heat exchanger fitted with louvered corner-curved V-baffles
(2023-02-01)
Jayranaiwachira, Nuthvipa
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Promvonge, Pongjet
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Thianpong, Chinaruk
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Skullong, Sompol
The 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>′) 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>′ is found to decline with the increment of P<inf>R</inf> and θ, whereas the minimal S˙<inf>gen</inf>′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.
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Thermohydraulic performance and entropy generation in heat exchanger tube with louvered winglet tapes
(2022-11-01)
Promvonge, Pongjet
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Skullong, Sompol
The 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>') was declined with the decrease in Re, P<inf>R</inf> and θ where the minimum S˙<inf>gen</inf>' 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.
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Enhanced thermal effectiveness of square duct with V-type double-baffles: Numerical study
(2024-09-01)
Promvonge, Pongjet
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Sripattanapipat, Somchai
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Thianpong, Chinaruk
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Skullong, Sompol
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Promthaisong, Pitak
The article puts forward three-dimensional computational research on heat transmission augmentation within a square channel containing 45o 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 45o. 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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Enhanced thermal performance in tubular heat exchanger contained with V-shaped baffles
(2021-02-25)
Promvonge, Pongjet
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Skullong, Sompol
The 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.
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Thermo-Hydraulic Performance of a Heat Exchanger Tube with Inserted Curved-Wing Tape Vortex Generators
(2024-10-24)
Koolnapadol, Narin
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Promvonge, Pongjet
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Promthaisong, Pitak
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Hoonpong, Panuwat
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Khanoknaiyakarn, Chitakorn
In the current study, thermal patterns and flow resistance in a heat exchange tube equipped with a curved-wing tape (CWT) vortex generator were experimentally analyzed to boost performance. A range of Reynolds numbers (Re) from 4130 to 25,370 was utilized in the experiment. The curved wings were arranged in forward array patterns for pitch length ratios (P/D = PR = 2.5, 2, and 1.5) and three wing attack angles (α = 10°, 20°, and 30°). The friction factor, f, and the Nusselt number, Nu, were utilized to quantify the pressure loss and heat transmission caused by the CWT insertion. The measured data reveal that utilizing the CWT resulted in a roughly 2.55-4.37 times greater increase in Nu than the smooth tube, whereas the rise in f is approximately 7.36-46.9 times. Raising the α value causes the Nu and f to trend upward, but increasing PR causes them to trend downward. The CWT's maximal thermal performance is approximately 1.58 at α = 10o and PR = 1.5. Correlations for f and Nu in the functional form of the CWT parameters have also been established.
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Effect of louvered curved-baffles on thermohydraulic performance in heat exchanger tube
(2023-02-01)
Jayranaiwachira, Nuthvipa
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Promvonge, Pongjet
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Thianpong, Chinaruk
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Promthaisong, Pitak
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Skullong, Sompol
The paper presents an experimental study of convection enhancement in a tube heat exchanger using louvered curved-baffle (LCB) vortex generator (VG). The heat transfer and pressure loss of air as a working fluid, flowing in an isothermal-fluxed tube were measured having Reynolds numbers (Re) between 4760 and 29,300. The LCB elements were arrayed on two tape sides in a V-shape with a 30° attack angle. At a fixed baffle height, the LCB had three axial pitch ratios (PR) from 0.5 to 1.5 and six louver angles (θ) from 0° to 90°. Thermal enhancement factor (TEF), Nusselt number (Nu), and friction factor (f) are often utilized to analyze the effect of VG geometrical variables on thermohydraulic performance. The measured results demonstrated that the LCB-inserted tube has a significantly larger Nu and f than a plain tube functioning alone, and that the Nu and f tend to rise when PR and θ decline. Using the LCB increases Nu and f by approximately 2.59-4.66 and 3.8-39.37 times, respectively. The maximal TEF is achieved for the LCB at PR = 1, θ = 45° and lower Re. Empirical correlations for Nu and f were evaluated and found to fit measured data well, with discrepancies by ± 9% and ±10%, respectively.
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Numerical Heat Transfer Investigation in a Solar Receiver Heat Exchanger Channel with Punched Elliptical-Winglet Vortex Generators
(2021-01-01)
Promthaisong, Pitak
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Promvonge, Pongjet
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Khanoknaiyakarn, Chitakorn
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Skullong, Sompol
Thermal performance in a solar receiver heat exchanger (SRX) channel with punched elliptical-winglet vortex generator (P-EW) mounted on the absorber plate is numerically examined for Reynolds number (Re) ranging from 4000 to 24,000. In the present simulation, the P-EW characteristics included three ratios of winglet pitches (P<inf>R</inf> = 2.0, 1.5 and 1.0) including four sizes of the perforated-holes (nondimensional hole diameter, d<inf>R</inf>= 0.0, 0.25, 0.417 and 0.583) at one value of the attack angle (α =30°) and relative height (B<inf>R</inf>= 0.48). The computation reveals that employing P-EW generally yields considerably large friction factor (f) and Nusselt number (Nu) than the flat-plate channel alone. The use of smaller hole size causes the rise in Nu and f. It is noticeable that counter-spinning vortices pairs generated by the multiple P-EW can induce the impinging flow onto the absorber plate together with the air jet coming out of the hole, leading to the rise in the heat transfer rate greater than the smooth flat-plate channel. The highest thermal performance of about 1.9 was seen for the one with P<inf>R</inf> = 1.5 and d<inf>R</inf> = 0.417.
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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
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Sripattanapipat, Somchai
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Suchatawat, Maturose
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Nakhchi, Mahdi Erfanian
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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
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Sripattanapipat, Somchai
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Promthaisong, Pitak
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Suchatawat, Maturose
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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.

Promvonge, Pongjet

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