Thianpong, Chinaruk

Preferred name

Thianpong, Chinaruk

Alternative Name

Thianpong, C.

Main Affiliation

School of Engineering

chinaruk.th@kmitl.ac.th

Now showing 1 - 10 of 11

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Heat transfer augmentation by helically twisted tapes as swirl and turbulence promoters
(2012-10-01)
Eiamsa-ard, S.
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Yongsiri, K.
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Nanan, K.
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Thianpong, C.
This paper describes heat transfer enhancement attributed to helically twisted tapes (HTTs). Each helically twisted tape was fabricated by twisting a straight tape to form a typical twisted tape then bending the twisted tape into a helical shape. The experiments were performed using HTTs with three twist ratios (y/. W) of 2, 2.5 and 3, three helical pitch ratios (p/. D) of 1, 1.5 and 2 for Reynolds number between 6000 and 20,000. The conventional helical tape (CHT) was also tested for comparison. The obtained results reveal that at similar conditions (y/. W and . p/. D), HTTs give lower Nusselt number and friction but higher thermal performance factor than CHTs. Heat transfer rate and friction factor increase as the tape twist ratio and helical pitch ratio decrease, while the thermal performance shows opposite trend. In the present range, the highest thermal performance factor of 1.29 is achieved by utilizing the tape with the largest twist ratio (y/. W=3) and helical pitch ratio (p/. D=2) at Reynolds number of 6000. © 2012 Elsevier B.V.
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Heat transfer evaluation of turbulent flows through gear-ring elements
(2017-01-01)
Ruengpayungsak, K.
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Wongcharee, K.
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Thianpong, C.
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Pimsarn, M.
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Chuwattanakul, V.
Heat transfer and friction loss characteristics in tubular heat exchangers with gear-ring turbulators (GR-Ts) have been experimentally and numerically investigated. The GR-Ts with different free-space length ratios (SR = s/D = 1.0, 2.0 and 3.0) and tooth numbers (N = 8, 16 and 24), were experimentally tested under constant wall heat flux in turbulent flow (Reynolds numbers from 6000 to 20,000). Air was used as the working fluid. The behaviors in a plain tube and the tube with a conventional ring turbulators (N = 0) were also studied for comparison. The results show that utilizing tubes with GR-Ts leads to the increases of heat transfer coefficient and pressure loss as compared to those associated with the use of a plain tube. Heat transfer enhancement and friction increase with decreasing free-space length ratio (SR) and tooth number (N). Among the investigated inserts, the conventional ring turbulators (N = 0) with free-space length ratio, SR = 1.0 give the highest heat transfer rate and friction factor at 2.7 times and 15.5 times of those of the plain tube. However, the maximum thermal performance factor of 1.3 is obtained by using the GR-Ts with the largest free-space length ratio and maximum tooth number (SR = 3.0 and N = 24). At SR = 3.0, the GR-Ts with tooth numbers (N) of 0, 8, 16 and 24 yield thermal performance factors up to 1.24, 1.26, 1.28 and 1.3, respectively. The numerical results are given for a better understanding of flow and heat transfer characteristics associated with the use of GR-Ts.
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Heat transfer enhancement in a tube using delta-winglet twisted tape inserts
(2010-03-01)
Eiamsa-ard, S.
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Wongcharee, K.
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Eiamsa-ard, P.
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Thianpong, C.
Heat transfer, flow friction and thermal performance factor characteristics in a tube fitted with delta-winglet twisted tape, using water as working fluid are investigated experimentally. Influences of the oblique delta-winglet twisted tape (O-DWT) and straight delta-winglet twisted tape (S-DWT) arrangements are also described. The experiments are conducted using the tapes with three twist ratios (y/w = 3, 4 and 5) and three depth of wing cut ratios (DR = d/w = 0.11, 0.21 and 0.32) over a Reynolds number range of 3000-27,000 in a uniform wall heat flux tube. The obtained results show that mean Nusselt number and mean friction factor in the tube with the delta-winglet twisted tape increase with decreasing twisted ratio (y/w) and increasing depth of wing cut ratio (DR). It is also observed that the O-DWT is more effective turbulator giving higher heat transfer coefficient than the S-DWT. Over the range considered, Nusselt number, friction factor and thermal performance factor in a tube with the O-DWT are, respectively, 1.04-1.64, 1.09-1.95, and 1.05-1.13 times of those in the tube with typical twisted tape (TT). Empirical correlations for predicting Nusselt number and friction factor have been employed. The predicted data are within ±10% for Nusselt number and ±10% for friction factor. © 2009 Elsevier Ltd. All rights reserved.
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Parametric study on thermal performance augmentation of TiO2/water nanofluids flowing a tube contained with dual counter twisted-tapes
(2024-07-01)
Thianpong, C.
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Wongcharee, K.
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Kunnarak, K.
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Chokphoemphun, S.
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Chamoli, S.
The study of compound heat transfer enhancement technique using dual counter twisted tapes (DCTs) together with TiO<inf>2</inf>/water nanofluids was carried out. The dual twisted tapes in form of counter-swirl tape arrangement were utilized at three twist ratios (y/w = 1.5, 2.0 and 2.5). TiO<inf>2</inf>/water nanofluids having three different volume concentrations (φ = 0.05, 0.10 and 0.15 %) were employed as the testing fluids. The results indicated that heat transfer rate, friction factor and thermal enhancement index rose with decreasing tape twisted ratio and elevating nanofluid concentration. The TiO<inf>2</inf>/water nanofluids applied in the present work offered higher Nu than pure water (the base fluid) by 7.3–10.0 %. The application of DCT with the smallest y/w of 1.5 and TiO<inf>2</inf>/water nanofluids with the largest φ of 0.15 vol% led to the highest thermal enhancement index (TEI) of 1.53, under the same pumping power criteria. Additionally, the k-nearest neighbor (k-NN) and artificial neural network (ANN) were developed to predict the thermal enhancement index (TEI). It was found that the k-NN and ANN models provided maximum R<sup>2</sup> values of 0.919 and 0.992 f, respectively.
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Thermal performance evaluation of heat exchangers fitted with twisted-ring turbulators
(2012-07-01)
Thianpong, C.
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Yongsiri, K.
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Nanan, K.
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Eiamsa-ard, S.
Heat transfer, friction factor and thermal performance characteristics in a tube equipped with twisted-rings (TRs) are experimentally investigated. The experiments were conducted using TRs with three different width ratios (W/D. =. 0.05, 0.1 and 0.15) and three pitch ratios of (p/D. =. 1, 1.5 and 2) for Reynolds numbers ranging from 6000 to 20,000 using air as a test fluid. The typical circular rings (CRs) were also tested for an assessment. The experimental results reveal that most TRs yield lower Nusselt numbers and friction factor than CRs, except at the largest width ratio (W/D. =. 0.15) and the smallest pitch ratio (p/D. =. 1.0). In addition, Nusselt number and friction factor increase as width ratio increases and pitch ratio decreases. However, a maximum thermal performance factor is associated by TRs with the smallest width ratio and pitch ratio. The empirical correlations of the heat transfer (Nu) and friction factor (f) are also included in this paper. © 2012 Elsevier Ltd.
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Thermal Performance Evaluation of a Channel Installed with Inclined-Baffle Turbulators
(2020-02-01)
Phila, A.
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Eiamsa-ard, S.
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Thianpong, C.
This study shed light on how heat transfer in a rectangular channel can be significantly enhanced by integrating it with inclined baffles. Experiments were performed to investigate the effect of the inclined baffles at different attack angles (θ) of 0° up to 165° in 15° incremental steps. The pitch length (between the consecutive baffles) to baffle height ratio (P/e) and the baffle height to channel height ratio (e/H) remained constant at 10 and 0.15, respectively. Experiments on a channel without baffles and one with typical transverse baffles (θ = 90°) were also conducted for comparison. Temperatures measured by the thermochromic liquid crystal image processing technique were employed for plotting the temperature contours on the heated surface. The Reynolds number associated with turbulent flow varied from 9000 to 24,000 under a constant wall heat flux scenario. The heat transfer and pressure drop were characterized by the Nusselt number (Nu) and friction factor (f), respectively. The results showed a promising ability of the inclined baffles to improve the heat transfer rate in the channel, however, this came at the price of an increased pressure drop in the system. The impact of the attack angle on heat transfer and thermal efficiency showed that a 60° attack angle was superior to other attack angles. The results were comparable to those for a 120° attack angle. Additionally, this attack angle enabled the system to accomplish a zenith thermal enhancement factor (η) of 1.11 at a Reynolds number of 9000.
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Thermal performance evaluation of a channel with twisted baffles installed: Effect of twisted baffle arrangement
(2026-03-01)
Eiamsa-ard, S.
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Pingta, S.
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Phila, A.
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Woncharee, K.
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Chamoli, S.
This research aims to introduce newly designed twisted baffle for enhancing heat transfer in solar air heater. This study examined the thermo-hydraulic performance of converging twisted baffles (C-TBs) and diverging twisted baffles (D-TBs) with different numbers of loops (n = 2, 4, 6, and 8) over a Reynolds number range (Re) of 6000–24,000. The results demonstrated that both converging twisted baffles and diverging twisted baffles significantly enhanced heat transfer compared to a smooth channel. The Nusselt number, friction factor, and thermal performance factor (TPF) increased as the number of loops decreased, attributed to stronger flow reattachment. Specifically, twisted baffles with 2, 4, 6, and 8 loops enhanced Nu by approximately 2.29–3.43, 2.02–3.05, 1.77–2.74, and 1.61–2.48 times, respectively, while the friction factor increased by 5.19–5.71, 4.61–5.01, 4.06–4.43, and 3.73–4.06 times, respectively. For a given number of loops, diverging twisted baffles consistently provided higher heat transfer enhancement than converging twisted baffles, albeit with slightly increased friction losses. Across the investigated range, the 2-loop diverging twisted baffles exhibited the best overall performance, achieving the highest Nusselt number ratio (Nu/Nu<inf>SC</inf> where Nu<inf>SC</inf> is the Nusselt number of the smooth channel) of 3.43 and a maximum thermal performance factor of 1.92 at Reynolds number of 6000, establishing it as the optimal configuration among those tested. This research contributes valuable design guidelines for selecting optimal baffle configurations, thereby supporting the development of more energy-efficient solar thermal systems.
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Heat transfer enhancement by tapered twisted tape inserts
(2015-10-01)
Piriyarungrod, N.
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Eiamsa-ard, S.
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Thianpong, C.
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Pimsarn, M.
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Nanan, K.
The effects of inserted tapered twisted tapes, their taper angle and twist ratio on heat transfer rate, pressure drop and thermal performance factor characteristics have been reported. The experiments were carried out by using the tapered twisted tapes with 4 different taper angles which θ= 0.0° (typical twisted tape), 0.3°, 0.6° and 0.9°. At each taper angle, the tapered twisted tapes were twisted at three different twist ratios (y/W) of 3.5, 4.0 and 4.5. All tapes were tested under turbulent flow regime for Reynolds numbers between 6000 and 20,000. A twist ratio is defined as the ratio of twist length (y) to twisted tape width at the large end (W). The plain tube was also tested for comparison. Heat transfer enhancement and friction loss increased with decreasing taper angle and twist ratio. Thermal performance factor tended to increase with increasing taper angle and decreasing tape twist ratio. For the present range, the tube with the tape with taper angle (θ) of 0.9° and twist ratio (y/W) of 3.5 yielded the maximum thermal performance factor of 1.05 at Reynolds number (Re) of 6000.
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Parametric study on thermal enhancement and flow characteristics in a heat exchanger tube installed with protruded baffle bundles
(2019-11-01)
Eiamsa-ard, S.
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Ruengpayungsak, K.
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Thianpong, C.
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Pimsarn, M.
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Chuwattanakul, V.
Influence of protruded baffle turbulators (P-BTs) on turbulent convective heat transfer rate and thermal performance behavior in round tubes was experimentally studied. The following geometrical parameters of P-BTs were considered (i) spacing ratio (SR = s/D<inf>ob</inf> = 1.0–3.0), (ii) diameter ratio (DR = d/D<inf>ob</inf> = 0.2–0.4), (iii) baffle orientation angle (θ = 0° (without rotation), 60°, 120° and 180°), and (iv) Reynolds number (Re = 6000 to 20,000). Air was used as working fluid at Prandtl number of Pr = 0.71. The plain tube data was examined for comparison with tube installed with protruded baffle turbulators (P-BTs). The experimental results obvious that increasing baffle orientation angle (θ), increasing diameter ratio (DR) and decreasing spacing ratio (SR) lead to the significant increases in heat transfer (Nu) and pressure loss (f). It can be also reveal that thermal performance (η) at a given Re considerably increases with the increasing spacing ratio (SR) and the reduction of diameter ratio (DR) and baffle orientation angle. The P-BTs with larger baffle orientation angle, induce stronger vortex ring and longitudinal vortex behind the baffles, give higher the thermal performance. Furthermore, all of empirical correlations (Nu, f and η) were derived as a function of Re and the protruded baffle turbulator (P-BT) geometry parameters including spacing ratio (SR), and protrusion-diameter ratio (DR).
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Flow and thermal mechanisms in a heat exchanger tube inserted with twisted cross-baffle turbulators
(2017-03-05)
Nanan, K.
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Thianpong, C.
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Pimsarn, M.
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Chuwattanakul, V.
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Eiamsa-ard, S.
The turbulent forced convective heat transfer behaviors in a tube inserted with baffle turbulators (typical straight baffles, straight cross-baffles, straight alternate-baffles, twisted-baffles, alternate twisted-baffles, and twisted cross-baffles) have been experimentally and numerically investigated. The influence of pitch ratio (P/D) from 1.0 to 2.0 and Reynolds numbers (Re) from 6000 to 20,000 are also reported. Among the studied turbulators, the twisted cross-baffles gave the highest heat transfer enhancement and thermal enhancement factor while the straight cross-baffles gave the lowest heat transfer rate and thermal enhancement factor. The twisted-baffles, alternate twisted-baffles, and twisted cross-baffles created high longitudinal vortex/swirl around the tube core. The strongest longitudinal vortex/swirl was achieved by the use of twisted cross-baffles. The recirculation flows were found in the tube fitted with straight baffles (a recirculation flow), straight alternate-baffles (double recirculation flows) and straight cross-baffles (quadruple recirculation flows). The heat transfer rate, friction factor and thermal enhancement factor increased with decreasing pitch ratio (P/D) and increasing Reynolds number (Re). At the optimum condition of the smallest pitch ratio (P/D = 1.0) and the lowest Reynolds number (Re = 6000), the twisted cross-baffles offered the highest thermal enhancement factor of 1.7.

Thianpong, Chinaruk

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