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 27

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Numerical heat transfer study of square duct equipped with novel flapped V-baffles
(2024-03-01)
Thianpong, Chinaruk
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Promvonge, Pongjet
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Skullong, Sompol
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Promthaisong, Pitak
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Nakhchi, Mahdi Erfanian
The paper describes a computational study of heat transfer enhancement inside a square duct with V-shaped flapped baffles located repeatedly on the bottom and top walls for fluid flowing with Reynolds numbers (Re) from 3000 to 21,000. The basic goal of this work is to attain the largest relative Nusselt number (Nu/Nu<inf>0</inf>) whilst maintaining the highest thermal performance to improve energy savings. A finite volume method was used in the computations, along with the Realizable k‒ε turbulent model. The variable baffle parameters considered first in the current simulation were the relative height/blockade ratio (B<inf>R</inf> = 0.05−0.2) and the flap angle of the baffle hole (β = 0° − 90°), while the fixed parameters included the attack angle (α = 60°), hole diameter ratio (d<inf>R</inf> = 0.5), and pitch ratio (P<inf>R</inf> = 0.5). To accomplish this goal, the previously mentioned parameters providing the best thermal performance were investigated further by extending the values of B<inf>R</inf> to 0.25−0.3, d<inf>R</inf> to 0.8 and α to 45°−30°. The simulation results indicate that the jet flowing from the flapped hole, as well as the vortices created by the baffle, can boost heat transfer and friction loss in comparison to the plain duct. In comparison, using a flapped baffle with β > 0° results in less friction loss, a greater thermal enhancement factor (TEF), and a higher Nusselt number than using a baffle with no flap. The first investigation disclosed that for B<inf>R</inf> = 0.2 and β = 20°, the greatest TEF of 2.19 with Nu/Nu<inf>0</inf> of 7.9 times are obtained. The extended study, on the other hand, showed that the highest TEF of roughly 2.49 with Nu/Nu<inf>0</inf> of 8.4 times are seen for α = 45°, d<inf>R</inf> = 0.8, B<inf>R</inf> = 0.25 and β = 20° at lowest Re. Thus, the flapped baffle provides a significant increase in Nu/Nu<inf>0</inf> and TEF over the baffle alone.
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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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Heat transfer in solar air duct with multi-V-ribbed absorber and grooved back-plate
(2021-04-01)
Promvonge, Pongjet
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Khanoknaiyakarn, Chitakorn
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Sripattanapipat, Somchai
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Skullong, Sompol
The article presents an experimental study on heat transfer and friction behaviors in a solar air duct fitted with multiple V-shaped ribs on the absorber and delta-grooves on the back plate. Measurements were carried out in the test duct having a cross-section of width, W = 300 mm and height, H = 27 mm. The air flow rate inside the duct was varied to have Reynolds numbers based on the duct hydraulic diameter from about 7000 to 30,000. Two vortex flow devices: rib and groove turbulators, were introduced to generate the vortex flows along the duct. In the test duct, the upper/absorber plate having a constant heat-flux was mounted repeatedly by multiple V-shaped thin ribs with an attack angle (α) of 45° relative to main flow direction while the lower/back plate was grooved periodically in the delta/triangular shape with an attack angle (θ) of 60°. In the present investigation, the geometrical parameters of the ribs included three different rib- to duct-height ratios (e/H = B<inf>R</inf> = 0.108, 0.162 and 0.217) and three rib-pitch to duct-height ratio (P/H = P<inf>R</inf> = 1.0, 1.5 and 2.0). The experimental results have shown that the duct with the V-ribbed absorber at B<inf>R</inf> = 0.217, P<inf>R</inf> = 1 in conjunction with the delta-grooved back plate has the greatest heat transfer and pressure loss. However, the use of the combined devices with P<inf>R</inf> = 1, B<inf>R</inf> = 0.108 leads to the highest thermal performance and also provides greater heat transfer and thermal performance than employing the V-rib or the delta-groove alone.
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Heat transfer behaviors in a solar air heater channel with multiple V-baffle vortex generators
(2014-12-01)
Tamna, Sombat
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Skullong, Sompol
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Thianpong, Chinaruk
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Promvonge, Pongjet
The article presents a study on heat transfer augmentation in a solar air heater channel fitted with multiple V-baffle vortex generators (BVG). During the test air was passed through the test channel under a uniform wall heat-flux of the absorber plate. The fluid flow and heat transfer characteristics are presented for Reynolds numbers based on the channel hydraulic diameter ranging from 4000 to 21,000. The V-baffles are applied at a relative baffle height (in terms of blockage ratio, BR. =. b/. H=. 0.25) and attack angle of 45° with respect to the main flow direction. The use of BVG in the channel is to generate multiple longitudinal vortex flows through the test channel to increase turbulence intensity and stronger mixing of fluid between the core and the near-wall flow. Influences of three different baffle-pitch to channel-height ratios (PR. =. P/. H=. 0.5, 1 and 2) on heat transfer and pressure drop in terms of respective Nusselt number and friction factor (or energy loss for propelling air through the channel) are examined. Three BVG arrangements, namely, one BVG wall (or single BVG), in-line and staggered BVGs on two opposite walls are also investigated. The experimental result reveals that the smaller PR provides the highest heat transfer and friction factor for all BVGs. The in-line BVG yields higher heat transfer and friction loss than the staggered and the single BVG. However, the single BVG with PR. =. 0.5 yields the highest thermal performance. To shed light of heat transfer mechanism, a numerical work is also conducted to investigate heat transfer and flow friction characteristics in the channel fitted with 45° BVGs and in comparison, the numerical results are in good agreement with experimental data.
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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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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><sup>′</sup>) 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.
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Heat transfer enhancement in a solar air heater channel with discrete V-baffles
(2014-01-01)
Soodkaew, Prawat
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Skullong, Sompol
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Promvonge, Pongjet
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Pairok, Watanyu
This article presents the study of heat transfer enhancement in a uniform heat-fluxed channel fitted with discrete V-shaped baffles. The experiments are carried out by varying airflow rate for Reynolds number ranging from 4100 to 22,000. The V-baffles with relative height ratio, e/H = 0.15 and the attack angle, a = 45o, are mounted repeatedly on the upper plate only, similar to an absorber plate of solar air heater systems. The effects of four baffle-pitch to channel-height ratios (PR= 0.5, 1.0, 1.5 and 2.0) on heat transfer in terms of Nusselt number and pressure loss in the form of friction factor are experimentally investigated. The experimental results show that the use of the discrete V-baffles leads to a considerable increase in Nusselt number and friction factor in comparison to the smooth channel alone. The V-baffled channel with PR=0.5 provides the highest heat transfer, friction factor and thermal enhancement factor. © (2014) Trans Tech Publications, Switzerland.
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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 = 10<sup>o</sup> 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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Thermal effectiveness and entropy-exergy estimation in a tube with punched double V-winglets
(2026-06-01)
Jayranaiwachira, Nuthvipa
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Sripattanapipat, Somchai
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Promvonge, Pongjet
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Erfanian Nakhchi, Mahdi
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Skullong, Sompol
Vortex generators are effective devices for enhancing heat transfer rates in heating or cooling systems with minimal frictional losses via the production of streamwise vortices. This research effort presents the perforated double V-winglet (P-DVW) and looks at how it affects heat transmission and friction when mounted inside a heat exchange tube that is consistently heated for producing multiple vortices whereas its flow is turbulent. Optimizing thermal performance for increased energy savings and maximizing the Nusselt number ( Nu ) to minimize heat exchanger size are the major goals. Thermal characteristics, including generated entropy and exergy efficiency, are explored in depth. A Reynolds number (Re) that varies from 4760 to 29,270 is employed to explore the friction and thermal features of the tube. The P-DVW parameters encompass attack angles of α<inf>2</inf> = 15° and α<inf>1</inf> = 30°, four porosity ratios ( A <inf>h</inf>/ A <inf>w</inf> = 0, 0.0188, 0.0523, and 0.1026), and three pitch ratios, P<inf>R</inf>, (0.75, 1, and 1.25), while maintaining a constant winglet height. At P<inf>R</inf> = 0.75 and A <inf>h</inf>/ A <inf>w</inf> = 0, the P-DVW exhibits peak f and Nu values around 23.83 and 5.31 times bigger than those of the plain tube, accordingly. Further, under the specified conditions, it yields minimal entropy production, while the optimal exergy efficiency is roughly 0.9829. The thermal effectiveness of P-DVW is anticipated to reach its maximum at 2.55 with Nu<inf>R</inf> = 4.54 at A <inf>h</inf>/ A <inf>w</inf> = 0.0523 and P<inf>R</inf> = 0.75 to reveal its actual benefits. Furthermore, the correlations of f , Nu , and TEF were determined for the examined range of values.

Promvonge, Pongjet

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