Thianpong, Chinaruk
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Preferred name
Thianpong, Chinaruk
Alternative Name
Thianpong, C.
Main Affiliation
Email
chinaruk.th@kmitl.ac.th
12 results
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Item type:Publication, Numerical heat transfer study of square duct equipped with novel flapped V-baffles(2024-03-01); ; - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Thermal performance of heat exchanger tube inserted with curved-winglet tapes(2018-01-25); ; ; 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. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Heat transfer and turbulent flow friction in a round tube with staggered-winglet perforated-tapes(2016-04-01); ; The article deals with thermal and flow resistance characteristics in a tubular heat exchanger fitted with staggered-winglet perforated tapes (WPT). The experiment was conducted in the test tube having a constant wall heat-flux for turbulent airflow, Reynolds number (Re) from 4180 to 26,000. The aim of using the WPT is to generate longitudinal vortex flows to disrupt thermal boundary layer on the tube wall and to provide stronger fluid mixing. The WPT having an winglet inclination angle of 30° was inserted into the test tube at five different winglet blockage ratios (B <inf>R</inf> = 0.1, 0.15, 0.2, 0.25 and 0.3) and three winglet pitch ratios (P <inf>R</inf> = 0.5, 1.0 and 1.5). To find an optimum thermal performance condition, the effect of B <inf>R</inf> and P <inf>R</inf> on the heat transfer and pressure loss due to flow friction in the tube is examined. The experimental results reveal that Nusselt number (Nu) and friction factor (f) for the WPT increase with the increment of B <inf>R</inf> but the reduction of P <inf>R</inf> . The highest thermal enhancement factor (TEF) of 1.71 is achieved by utilizing the WPT with B <inf>R</inf> = 0.15, P <inf>R</inf> = 1.0 at Re = 4180. Compared to staggered-winglet typical non-perforated tape (WTT), the WPT yields the TEF of about 1.2 times higher than the WTT. Correlations of Nu, f and TEF for the WPT and the WTT are also proposed. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Thermal performance in solar air heater with perforated-winglet-type vortex generator(2018-08-01); ; An experimental and numerical study of turbulent convective heat transfer in a solar air heater duct with winglet-type vortex generators (WVGs) placed on the absorber plate is presented. Air as the test fluid enters the duct having a uniform wall heat-flux applied on the upper wall or the absorber plate with Reynolds number from 4100 to 25,500. Two types of WVGs are introduced: rectangular (RWVG) and trapezoidal (TWVG) WVGs, in order to create multiple vortex flows along the duct. The WVG parameters in the present study include two relative height (B<inf>R</inf> = e/H = 0.2 and 0.48), three longitudinal pitch ratios (P<inf>R</inf> = P<inf>l</inf>/H = 1, 1.5 and 2) and a single attack angle, α = 30°. The experimental result reveals that the RWVG with B<inf>R</inf> = 0.48 and P<inf>R</inf> = 1 provides the highest heat transfer and friction factor at about 7.1 and 109.5 times above the flat duct, respectively while the TWVG with B<inf>R</inf> = 0.2 and P<inf>R</inf> = 1.5 yields the maximum thermal performance around 1.84. Then, to improve the performance by reducing the substantial pressure loss, both the WVGs with B<inf>R</inf> = 0.48 and P<inf>R</inf> = 1.5 are modified to be perforated rectangular and trapezoidal winglet-type vortex generators (P-RWVG and P-TWVG) with four different punched hole/pore diameters (d = 1, 3, 5 and 7 mm) on their central area. The investigation indicates that among the perforated WVGs, the P-RWVG at d = 1 mm yields the highest heat transfer and friction factor up to 6.78 and 84.32 times higher than the smooth duct but the best thermal performance of about 2.01 is found for the P-TWVG with d = 5 mm. To explore the flow and heat transfer pattern, a 3D numerical flow simulation is performed and validated with available measurements where both the numerical and measured results are in good agreement. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Experimental and numerical heat transfer investigation in a tubular heat exchanger with delta-wing tape inserts(2016-11-01); ; Effects of insertion of a straight tape with double-sided delta wing pairs (called “delta-wing tape”, DWT) used as a longitudinal vortex generator (LVG) on forced convective heat transfer and flow friction characteristics in a uniform heat-flux heat exchanger tube are investigated experimentally and numerically in the present work. The experiment is conducted for turbulent airflow with the Reynolds number (Re) from 4200 to 25,500. The delta wings are in a forward-wing arrangement with three wing inclination angles (α = 30°, 45° and 60°) and with five ratios of wing-pitch to tube-diameter (P/D = PR = 0.5, 1.0, 1.5, 2.0 and 2.5). Influences of the DWT insert on heat transfer in terms of Nusselt number (Nu) and pressure drop in the form of friction factor (f) are examined. The results indicate that the DWT provides the increases in Nu and f up to 505% and 69 times above the plain tube, respectively and the maximum thermal enhancement factor (TEF) is at 1.49. The 60° DWT with PR = 0.5 yields the highest Nu and f but the 30° one with PR = 1.0 gives the best TEF. To understand the flow structure and heat transfer mechanism, a three dimensional CFD simulation of the inserted tube is also performed. The simulated results are validated and are in good agreement with the current measurements. A simulated heat transfer and fluid flow structure is also reported. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Thermal performance in solar air heater channel with combined wavy-groove and perforated-delta wing vortex generators(2016-05-05); ; An experimental investigation on thermal performance improvement in a solar air heater channel with combined wavy-groove and delta-wing vortex generator (WVG) placed on the absorber plate having a uniform wall heat-flux is carried out. The Reynolds number based on the hydraulic diameter of the channel ranges from 4800 to 23,000. The effect of the combined groove and WVG on the heat transfer and pressure drop in the channel in terms of respective Nusselt number and friction factor is examined. Investigated parameters of the WVG mounted on the grooved absorber are three wing porosity area ratios (called porosity ratio, A<inf>h</inf>/A<inf>w</inf> = 0.031, 0.085 and 0.167) and four groove-wing distance to channel-height ratios (g/H = 0.4, 0.5, 0.75 and 1) at a single attack angle (α = 45°). The experimental result reveals that at g/H = 0.5, the smaller A<inf>h</inf>/A<inf>w</inf> provides the highest Nusselt number and friction factor around 6 and 30 times over the smooth channel, respectively, but the optimum thermal performance is at A<inf>h</inf>/A<inf>w</inf> = 0.085 and g/H = 0.5. The combined devices give the thermal performance augmentation at about 37.7-46.3% higher than the groove alone and also at about 1.5-12.5% above the combined groove and non-perforated WVG (without hole). - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Thermal behaviors in a round tube equipped with quadruple perforated-delta-winglet pairs(2017-01-01); ; The article deals with an experimental investigation of enhancing convective heat transfer in a heated circular tube with pairs of perforated-delta-winglets placed repeatedly on a perforated-cross-tape (PW-XT). The perforated-delta-winglets are placed in inline array and a triangular-hole is punched on each winglet to reduce the friction loss. The aim at using the PW-XT insert is to produce streamwise-vortex flows in the tube to reduce the thickness of thermal boundary layer and to increase fluid mixing of the flow. The involved winglet parameters are composed of relative winglet height or blockage ratio, (B<inf>R</inf> = b/D = 0.1, 0.15, 0.2 and 0.25) and relative winglet pitch or pitch ratio, (P<inf>R</inf> = P/D = 0.5, 1.0, 1.5 and 2.0) and those are performed at a single delta-winglet inclination/attack angle, α = 30° and a winglet porosity ratio, A<inf>p</inf>/A<inf>w</inf> = 0.359 for Reynolds number from 4180 to 26,000. The present results of heat transfer and pressure loss displayed in terms of respective Nusselt number (Nu) and friction factor (f) show that Nu increases with increasing B<inf>R</inf>but with decreasing P<inf>R</inf>. Nu for the PW-XT insert is in a range of 1.96–5.06 times while f increases around 2.06–35.68 times above the plain tube alone. To estimate the real merits of the PW-XT, the thermal enhancement factor (TEF) is evaluated and found to be a maximum around 1.902 at B<inf>R</inf> = 0.15, P<inf>R</inf> = 1.0. In comparison, the PW-XT gives considerably higher TEF than the typical four delta-winglet pairs placed on the cross-tape (TW-XT) having the highest TEF around 1.72. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Thermal performance of turbulent flow in a solar air heater channel with rib-groove turbulators(2014-01-01); ; The paper presents an experimental study on turbulent flow and heat transfer characteristics in a solar air heater channel fitted with combined wavy-rib and groove turbulators. The experiments are performed by controlling the airflow rate to obtain Reynolds numbers in the range of 4000 to 21,000. To produce recirculation flow in the tested channel having a constant heat-flux on the upperwall only, the triangular wavy ribs are placed repeatedly on the tested grooved channelwalls. Three test cases of different rib-pitch to channel-height ratios (PR = P/ H = 0.5, 1 and 2) with a single rib-to-channel height ratio (BR = b/H = 0.25) are introduced in the present work. The wavy ribs are placed with the attack angle of 45° relative to main flow direction. There are three types of rib arrangements, namely, rib-groove on the upper wall only, inline rib-groove, and staggered ribinline groove on two principal walls. The experimental result reveals that the combined rib-groove on both the upper and lowerwalls of the test channel provides the highest heat transfer rate and friction factor in comparison with the smooth channel with/without ribs. However, the ribbed-grooved upper wall at PR = 0.5 yields the highest thermal performance. The combined rib-groove turbulator is found to be considerably higher thermal performance than the groove alone. © 2013 Elsevier Ltd. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Effect of louvered curved-baffles on thermohydraulic performance in heat exchanger tube(2023-02-01); ; ; - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Experimental and numerical heat transfer investigation in turbulent square-duct flow through oblique horseshoe baffles(2016-01-01); ; An experimental and numerical work has been carried out to study the heat transfer enhancement in a heat exchanger square-duct fitted with 30° oblique horseshoe baffles (HB). In the current work, air is passed through the HB-inserted duct having a constant surface heat-flux. The air flow and heat transfer behaviors are presented for turbulent flow region, Reynolds number ranging from 4000 to 25,000. The pertinent parameters of the 30° HB elements include three relative baffle-pitches (P<inf>R</inf>=P/H=0.5, 1 and 2) and five relative baffle heights (B<inf>R</inf>=b/H=0.05, 0.1, 0.15, 0.2 and 0.25). Influences of those parameters on heat transfer and energy loss due to friction in terms of Nusselt number and friction factor, respectively are studied. The experimental result shows that at a given B<inf>R</inf>, the smallest pitch spacing (P<inf>R</inf>=0.5) provides the highest heat transfer and friction factor. The HB at B<inf>R</inf>=0.25 and P<inf>R</inf>=0.5 yields the highest heat transfer and friction factor but the one at B<inf>R</inf>=0.2 and P<inf>R</inf>=1 gives the maximum thermal performance. In addition, the thermal performance of using the HB is much higher than that of the wire coil insert, in comparison with other turbulators. To understand the heat transfer mechanism, a numerical inserted-duct flow simulation is also conducted and the obtained numerical results are in good agreement with measurements. Numerical flow and heat transfer behaviors such as streamlines, temperature and Nusselt number contours of the duct flow model are also reported.