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 38

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Augmented thermal effectiveness in solar air receiver with flapped curved winglets: Experimental and numerical analysis
(2025-12-01)
Sripattanapipat, Somchai
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Promvonge, Pongjet
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Jayranaiwachira, Nuthvipa
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Promthaisong, Pitak
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Nakhchi, Mahdi Erfanian
Thermal effectiveness was examined on a solar air receiver equipped with a new lengthwise vortex generator, namely a flapped curved winglet (FCW) mounted on the absorber, utilizing experimental and numerical approaches. Two arrays were employed to assemble two FCWs on the absorber at an angle of attack (α = 59.5°). The FCWs' V-tips were orientated upstream (VU-FCW) and downstream (VD-FCW). Air served as the working fluid, entering a constantly heat-fluxed channel at Reynolds numbers (Re) varying from 5280 to 22,510. Three relative winglet pitches (P<inf>R</inf> = P/H = 1.0–2.0), five winglet-mounted flap angles (β = 0° - 90°), and one winglet blockage ratio (b/H=B<inf>R</inf> = 0.6) were among the major factors. According to the findings, lowering P<inf>R</inf> and β greatly enhances the f (friction factor) and Nu (Nusselt number) of the two FCW arrays. The FCW with P<inf>R</inf> = 1.0 and β = 0° has the largest Nu and f values, approximately 8.3 and 77.39 times bigger than the smooth flat channel, as per the test data. The maximal thermal effectiveness factors (TEF) of the VD-FCW and VU-FCW were approximately 2.83 and 2.61, respectively, at comparable β = 45° and P<inf>R</inf> = 1.5. The f and Nu correlations in employing FCW were also provided. A 3D computational analysis employing the realizable k-ε turbulence model was conducted to examine heat transmission and flow patterns, with the corresponding measured data validating the expected results. The numerical and measured data sets yielded consistent results, and the FCW's heat transmission mechanism was also described.
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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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Thermal performance of heat exchanger tube inserted with curved-winglet tapes
(2018-01-25)
Skullong, Sompol
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Promvonge, Pongjet
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Thianpong, Chinaruk
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Jayranaiwachira, Nuthvipa
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Pimsarn, Monsak
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.
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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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Thermal characteristics in solar air duct with V-shaped flapped-baffles and chamfered-grooves
(2021-06-01)
Promvonge, Pongjet
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Skullong, Sompol
The article deals with augmenting the thermohydraulic performance of a solar heat exchanger duct with combined V-shaped baffle-and-groove vortex generators (VGs). Heat transfer behaviors from the combined VGs mounted in the duct absorber were investigated experimentally. Two VGs mounted on the absorber plate, the V-shaped flapped-baffle and chamfered-groove with a similar attack angle, α = 45°, were arranged by two arrays: V-apex pointing upstream (VU) and pointing downstream (VD). The vital purpose of using the flapped-wing mounted on the baffle (called “flapped baffle”) is to decline the pressure loss from the baffle without deterioration of the main vortices behind. The present experiment was carried out to encompass Reynolds number (Re) in a range of 5290 to 22,600, using air as a working fluid. The pertinent parameters of grooves were three groove pitch ratios (P<inf>R</inf> = 1.0, 1.5 and 2.0) while the baffle characteristics included four flap angles of the flap mounted on the baffle central area (β = 30°, 45°, 60° and 90°), three relative baffle pitches (P<inf>R</inf> = 1.0, 1.5 and 2.0) at one baffle height. Effects of the baffle and groove parameters as stated above on Nusselt number (Nu), friction factor (f) and thermal enhancement factor (TEF) were examined. The experimental results have revealed that the use of flapped-baffle and groove VG devices at P<inf>R</inf> =1.0 and β = 30° gives the largest f and Nu, especially for the VU case owing to strongly impinging jets issuing from the flap opening on the absorber surface area behind the baffle. Specifically, the maximum TEF is found to be 2.68 for the combined VU devices with P<inf>R</inf>=1.5, β = 45° and Re=5290. With these measured data, the Nu and f correlations are also determined.
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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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Thermal-hydraulic performance enhancement of solar receiver channel by flapped V-baffles
(2022-06-01)
Promvonge, Pongjet
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Skullong, Sompol
Thermal-hydraulic performance investigation in a solar receiver channel equipped with a vortex flow generator, namely, flapped V-shaped baffle (FVB) on the absorber has been experimentally carried out. The purpose of using the square flaps on the V-baffle was to decline the pressure drag by directing the impact air to the absorber surface. The working fluid was air flowing into the uniform heat-fluxed channel at Reynolds number (Re) between 5300 and 23,600. The FVBs with 45°attack angle (α) were placed periodically on the absorber with the upstream V-apex arrangement. The FVB characteristics included three relative baffle-pitches (R<inf>P</inf>) and four flap angles (β)at one relative baffle height (R<inf>B</inf>=0.5) and flap length (b<inf>1</inf>/b = 0.4) were examined to obtain the optimum R<inf>P</inf> and β values. The present investigation has revealed that the FVB gives a considerable decrease in friction loss when compared with the solid V-baffle (β = 0) while the heat transfer rate reduces a little. The FVB with β = 45°, R<inf>P</inf> = 1.5 yields the greatest thermal performance around 2.5 as a result of the injecting air flows from the flap opening aside from the reduced friction loss. For the current experimental data, the Nusselt number and friction factor correlations were determined in the form of a function of the geometric FVB parameters and Re.
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Effect of louver-perforated V-type baffles on thermal effectiveness and entropy in round tube
(2025-08-01)
Promvonge, Pongjet
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Sripattanapipat, Somchai
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Suchatawat, Maturose
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Nakhchi, Mahdi Erfanian
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Skullong, Sompol
An experimental investigation was conducted to assess the influence of insertion of a louver-perforated V-type baffle (LVB) vortex generator into a consistent heat-fluxed tube on thermal performance. This study aimed to optimize thermal effectiveness to boost energy savings and reduce the heat exchanger size. The experiments focused on investigating the thermal features, as well as estimating the entropy of turbulent flow at Reynolds numbers (Re) varying between 4750 and 29,290. The LVBs were positioned in two different arrays on a supporting tape during the present experiment: “V-down” and “V-up,” with the V-apex oriented upstream and downstream, respectively, at a fixed attack angle (α = 52°). At one relative baffle height (B<inf>R</inf> = 0.3) and pitch (P<inf>R</inf> = 1.0), the LVBs dealt with six louver flapped angles (θ = 0°, 10°, 20°, 30°, 45°, and 90°) in addition to three louver-hole sizes and locations (θ<inf>1</inf>, θ<inf>2</inf> and θ<inf>12</inf>). Comparative analysis was also conducted on data obtained from the current smooth tube. According to the findings, the louver angle θ<inf>1</inf> = 20°, located on the baffle's trailing end, had the greatest relative Nusselt number (Nu<inf>R</inf>), which was 5.9 times for V-down and 6.38 times for V-up. Furthermore, compared to the V-down and V-up solid baffles (θ = 0°), their friction losses were lessened. The V-up LVB reached its minimum value at θ<inf>1</inf> = 20°, corresponding to the lowest Re. At θ<inf>1</inf> = 20°, the V-up LVB attained its minimum entropy generation (S˙<inf>gen</inf>′) and maximum reduced entropy factor (S<inf>R</inf>) around 20.3. At a comparable θ<inf>1</inf> = 20°, the maximal thermal effectiveness factor (TEF) of V-down and V-up were approximately 2.39 and 2.59, respectively. The estimation and documentation of correlations were also performed for the parameters under consideration, namely Nu, f, and TEF.

Promvonge, Pongjet

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