Jedsadaratanachai, Withada
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Jedsadaratanachai, Withada
Alternative Name
Jedsadaratanachai, W.
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withada.je@kmitl.ac.th
13 results
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Item type:Publication, Numerical simulation of Al2O3-water nanofluid flow and heat transfer in a tube with angled rings(2014-01-01); - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Heat transfer and flowfriction behaviors in a channel with multiple 30° V-ribs(2014-01-01); The paper presents an experimental study on heat transfer and flow friction characteristics in a rectangular channel fitted with periodically rectangular V-ribs. The multiple V-rib turbulators are tested in the channel having an aspect ratio (width to height ratio), AR=10 and height, H= 30 mm, with three rib-to-channel height ratios (e/H=0.2, 0.3, and 0.4), two rib-pitch to channel-height ratios (PR=P<inf>1</inf>/H= 3 and 4) and a single attack angle (α=30°). The upper plate of channel is uniformly heated at a constant heat-flux. The experiment has been conducted by varying airflow velocity in order to obtain the Reynolds number range from 5000 to 24,000. The experimental results show a significant effect of the presence of the ribs on the heat transfer rate and pressure drop over the smooth channel. The measured data indicates that the V-rib turbulators with e/H = 0.4 and PR =3 yields the highest heat transfer rate and friction loss. All the V-rib turbulators perform much higher than the smooth channel with no rib. © 2014 Asian Institute of Technology. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Thermal characteristics in turbulent channel flows with V-baffle vortex generators(2014-01-01); ; Eiamsa-Ard, S.Experimental work has been performed to examine the effects of V-baffle vortex generators on the heat transfer and friction characteristics in a channel under a constant heat flux boundary condition. In the experiments, V-baffles at different pitch ratios (PR=P/e = 4.0, 6.0 and 8.0) were carried out. Measurements were carried out for a channel of one aspect ratio, AR = W/H = 4.0 and duct height, H= 40 mm with baffle height, e = 8 mm. Experiments were conducted for the Reynolds number range of 6000 to 22,000. The distributions of temperature and local Nusselt number on bottom channel wall were observed with thermochromic liquid crystal (TLC) sheet. Isothermal friction factors were also taken and presented. The obtained results demonstrate that heat transfer increases with the increase of Reynolds number, whereas friction factor (f) shows the opposite trend. Experimental results also show that the channels with V-baffle at the highest pitch ratio (PR = 8.0) provide highest heat transfer than others. © 2014 Asian Institute of Technology. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Heat transfer improvement in a square duct with diagonal inclined ribs(2014-01-01); ; Limkul, ThitipatThis research presents a numerical study of turbulent periodic flow and heat transfer in three-dimensional isothermal-fluxed square duct with diagonal inclined rib inserted. The fluid flow and heat transfer characteristics are presented for Reynolds numbers in the range of 4000 to 20,000. The computations based on the finite volume method, and the SIMPLE algorithm has been implemented. Effects of rib pitch ratios (0.5 to 2) at a single blockage ratio of 0.2 and attack angle of 60° on heat transfer and friction factor in the duct are examined and their results of the inclined rib are also compared with those of the smooth duct. It is found that the inclined rib provides higher heat transfer rate and friction factor than the smooth duct for all cases. In addition, the decreasing of the pitch ratio leads to the rise in the Nusselt number and friction factor. © (2014) Trans Tech Publications, Switzerland. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, 3D simulation on flow behavior and heat transfer in a circular tube with inclined different arrangement of thin rib(2013-01-28); This work deals with periodic flow, friction loss and heat transfer characteristics in a constant temperature-surfaced circular tube fitted with rib vortex generators (RVG). The computations are based on the finite volume method with the SIMPLE algorithm implemented. The fluid flow and heat transfer behaviors are presented for Reynolds numbers ranging from 100 to 1000. To generate two main vortex flows through the tested section, the 45<sup>o</sup> RVGs are mounted repeatedly in in-line arrangements on the top and bottom walls and in the central area of the tested section. Effects of different RVG heights, BR in a range from 0.1D to 0.3D with a single pitch of 1.5D on heat transfer and friction losses in the test section are examined. It is apparent that the vortex flows created by the RVG exist and help to induce periodically impinging flows on a sidewall leading to drastic increase in the heat transfer rate over the test section. The computational results reveal that the optimum thermal performance is about 2.38 for using the RVG height of 0.2D for the RVG placed on the tube walls at the highest Re value. © (2013) Trans Tech Publications, Switzerland. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Numerical study of laminar flow and heat transfer in square channel with 30° inline angled baffle turbulators(2010-08-01); ; The article presents a numerical investigation on periodic laminar flow and heat transfer behaviors in a three-dimensional isothermal wall square-channel fitted with 30°-angled baffles on two opposite channel walls. The computations based on the finite volume method with the SIMPLE algorithm have been conducted for the fluid flow in terms of Reynolds numbers ranging from 100 to 2000. To generate a pair of streamwise counter-rotating vortex (P-vortex) flows through the tested channel, the angled baffles with the attack angle of 30° are mounted periodically and inline arrangement on the lower and upper channel walls. Effects of different baffle heights and three pitch ratios on heat transfer and flow behaviors in the channel are examined. It appears that P-vortex flows help to induce impinging flows over the baffle leading end side and the inter-baffle cavity walls resulting in drastic increase in heat transfer rate over the test channel. The computational results reveal that the maximum thermal enhancement factors for the baffle with PR = 1, 1.5 and 2 are found to be about 3.6, 3.8 and 4.0 at BR = 0.2, 0.2 and 0.15, respectively. © 2010 Elsevier Ltd. All rights reserved. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Heat transfer augmentation in a round tube with 60° winglet pair inserts(2014-01-01); ; Chompookham, TeerapatThe experimental study on heat transfer enhancement in a tubular heat exchanger fitted with 60o winglet pairs is carried out by varying airflow velocity in turbulent region in the test section having a constant wall heat-flux. Effects of three blockage ratios (BR=e/D= 0.1, 0.15 and 0.2) and three pitch ratios (PR=P/D= 1, 1.5 and 2) of the winglet pairs on heat transfer rates in the terms of Nusselt number (Nu) and pressure loss in the form of friction factor (f) are examined. The experimental results illustrated that the tube with winglet pair insert provides the heat transfer rate higher than the smooth tube around 1.7 to 2.6 times, depending upon operating conditions. The thermal enhancement factor for using the winglet-pair turbulator is in a range of 1.03 - 1.31. © (2014) Trans Tech Publications, Switzerland. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Thermal performance in a tubular heat exchanger with deltawinglets(2018-08-14); ; The paper presents an experimental heat transfer enhancement study in a tubular heat exchanger fitted with delta-winglets. The experimental work was conducted by varying the airflow rate in the test tube having a constant wall heat-flux for turbulent regime, Reynolds number (Re) from 5200 to 23,000. Effects of three pitch ratios (PR=P/D=1.5, 2.0 and 3.0) and two attack angles, α = 45° and 60°, of the winglets at a single blockage ratio (BR=b/D = 0.15) on thermal characteristics are examined. The experimental results show that the winglet-inserted tube yields, respectively, the heat transfer, friction factor and thermal performance in the form of TEF around 1.99-4.08, 4.9-14.3 times higher than the plain tube and 0.85-1.85, depending on the operating condition. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Computational investigation on fully developed periodic laminar flow structure in baffled circular tube with various BRThis paper presents a 3D numerical analysis of fully developed periodic laminar flow in a circular tube fitted with 45° inclined baffles with inline arrangement. The computations are based on a finite volume method, and the SIMPLE algorithm has been implemented. The characteristics of fluid flow are presented for Reynolds number, Re = 100-1000, based on the hydraulic diameter (D) of the tube. The angled baffles were repeatedly inserted at the middle of the test tube with inline arrangement to generate vortex flows over the tested tube. Effects of different Reynolds numbers and blockage ratios (b/D, BR) with a single pitch ratio of 1 on flow structure in the tested tube were emphasized. The flows in baffled tube show periodic flow at x/D ≈ 2-3, and become a fully developed periodic flow profiles at x/D ≈ 6-7, depending on Re, BR and transverse plane positions. The computational results reveal that the higher of BR and closer position of turbulators, the faster of fully developed periodic flow profiles. © 2014 Withada Jedsadaratanachai et al. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, 3D simulation of laminar flow and heat transfer in V-baffled square channelThe article presents a numerical investigation on laminar flow and heat transfer characteristics in a three-dimensional isothermal wall square-channel fitted with inline 45̊ V-shaped baffles on two opposite walls. The computations based on the finite volume method with the SIMPLE algorithm have been conducted for the airflow in terms of Reynolds numbers ranging from 200 to 2000. The inline V-baffles with its V-tip pointing downstream and the attack angle (or half V-apex angle) of 45̊ relative to the flow direction are mounted repeatedly on the lower and upper walls. The baffled channel flow shows a fully developed periodic flow and heat transfer profile for BR=0.2 at x/D≊8 downstream of the inlet. Influences of different baffle height ratios (BR) and pitch ratios, (PR) on thermal behaviors for a fully developed periodic condition are investigated. It is apparent that the longitudinal counter-rotating vortex flows created by the V-baffle can induce impingement/attachment flows over the walls resulting in greater increase in heat transfer over the test channel. Apart from speeding up the fully developed periodic flow pattern, the rise of the BR leads to the increase in Nu/Nu <inf>0</inf> and f/f <inf>0</inf> values while that of the PR provides an opposite trend. The V-baffle performs better than the angled baffle at a similar condition. The V-baffle with BR=0.2 and PR=1.5 yields the maximum thermal performance of about 3.8 whereas the Nu/Nu <inf>0</inf> is some 14 times above the smooth channel at higher Re. © 2011 Elsevier Ltd.