Thianpong, Chinaruk

Preferred name

Thianpong, Chinaruk

Alternative Name

Thianpong, C.

Main Affiliation

School of Engineering

chinaruk.th@kmitl.ac.th

Now showing 1 - 4 of 4

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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
;
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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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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Effect of trapezoidal louvered winglets on increased heat transfer and exergy in tubular heat exchanger
(2024-10-01)
Promvonge, Pongjet
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Thianpong, Chinaruk
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Jayranaiwachira, Nuthvipa
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Nakhchi, Mahdi Erfanian
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Skullong, Sompol
The effect of inserting a trapezoidal louvered winglet tape (TLWT) into a uniformly heat-fluxed tube on its thermal effectiveness was studied experimentally. The exergy and entropy analyses for turbulent flows, as well as frictional loss and thermal features, were highlighted as key aspects of the experimental finding for the Reynolds number which measured between about 4700 and 30,000. Because fixing baffles to the curved shape of tube wall presented a challenge, the baffles were consequently positioned on double surfaces of a flat tape. Six values of the louver angle (θ<inf>1</inf> = 0°, 25°, 30°, 45°, 60°, and 90°) and three values of the relative pitch of winglet (P<inf>R</inf> = 1.0, 1.5, and 2.0) were employed in the arrangement of TLWTs, with the V-apex oriented upstream (V-up). Each of these had only a fixed height (B<inf>R</inf> = 0.25) and angle of attack (α = 30°). The winglets were utilized to induce streamwise vortices which can hinder the boundary layer formation, while the louvered openings were adopted to lessen pressure drop without significantly impacting the primary vortices. The experiment results disclosed that the smallest θ<inf>1</inf> and P<inf>R</inf> produced the largest relative friction factor (f<inf>R</inf>) and Nu<inf>R</inf>, which were about 13.57 and 4.04 times higher, while P<inf>R</inf> = 1 and θ<inf>1</inf> = 45° provide the greatest TEF of about 2.27. The greatest exergy efficiency (η<inf>Ex</inf>) resulting from the TLWT was reached at θ<inf>1</inf> = 0°, but the generation of entropy (S˙<inf>g</inf><sup>′</sup>) dropped with lowering θ<inf>1</inf> and Re. A further examination, however, showed that the best scenario with α = 60° and staggered arrays is more desirable since it yields the largest TEF of 2.45 at θ<inf>1</inf> = 45° and P<inf>R</inf> = 1. For the range of parameters under consideration, the Nu and f correlations were additionally established.
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Thermal-hydraulic performance of solar receiver duct with inclined punched-ribs and grooves
(2022-11-01)
Jayranaiwachira, Nuthvipa
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Promvonge, Pongjet
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Thianpong, Chinaruk
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Skullong, Sompol
The article presents an experimental study on turbulent airflow friction and thermal behaviors in a solar receiver heat exchanger duct mounted with combined inclined chamfered-groove and turbulators. The experimental work was conducted for Reynolds numbers from 5,300 to 24,000, based on the hydraulic duct diameter. The 45°-inclined punched-ribs and grooves were placed periodically on the absorber plate. The punched-rib parameters were four inclination angles (β = 0°, 45°, 90° and 135°) of the punched holes and three relative rib pitches (PR = 1, 1.5 and 2) whereas only a rib blockage ratio (BR = 0.5) and an angle of attack (α) of 45° were fixed. Similarly, the parameters of the grooves included only three groove-pitch ratios (PR), similar to the rib pitches and one groove blockage ratio (BR = 0.2). The experimental result has revealed that the combination of rib-groove turbulators at β = 0° (solid rib) and PR = 1 gives the maximum heat transfer rate and friction loss while the greatest thermal enhancement factor of 2.1 was found at β = 45°, PR = 1. Moreover, the friction loss and heat transfer correlations for this thermal system were determined.

Thianpong, Chinaruk

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