Chuwattanakul, Varesa
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Preferred name
Chuwattanakul, Varesa
Alternative Name
Chuwattanakul, V.
Main Affiliation
Email
varesa.ch@kmitl.ac.th
9 results
Now showing 1 - 9 of 9
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Item type:Publication, Simulation of turbulent heat transfer characteristics in a corrugated tube with five-channel twisted tape inserts(2017-08-31); ; Eiamsa-Ard, SmithThe article presents a numerical analysis of turbulent periodic flow and heat transfer characteristics in a five-start spiral corrugated tube combined with five-channel twisted tape. Influences of the five-channel twisted tape with tape width ratio, w/D=0.10, 0.20, 0.30, 0.40 and 0.44 at constant the twisted length ratio, y/D=2.0 were described. The results were reported in term of flow structure, temperature distribution, TKE field, local Nusselt number distribution on the wall, Nusselt number ratio, friction factor ratio and thermal enhancement factor. The five-start spiral corrugated tube combined with five-channel twisted tape showed a main swirl flow and secondary swirl flow along the tube due to the induction of the spiral groove while the smooth circular tube appeared the straight only and the five-start spiral corrugated tube with the five-channel twisted tape at w/D=0.44 appeared the main swirl flow only. The swirl flow help to increase fluid mixing and increase in heat transfer rate over the smooth circular tube. The increase in the w/D lead to the rise of Nusselt number and friction factor. The result showed that the optimum thermal enhancement factor of about 1.16was found at the five-start spiral corrugated tube without the five-channel twisted tape and at w/D=0.44. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, TiO2/water Nanofluid Heat Transfer in Heat Exchanger Equipped with Double Twisted-Tape Inserts(2018-05-14) - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Influence of delta-winged dual twisted tapes insertion on heat transfer and pressure drop characteristics(2015-01-01); Eiamsa-Ard, SmithThe article presents the heat transfer and friction factor characteristics of turbulent flow in a uniform wall heat flux tube inserted with delta-winged dual twisted tapes. The typical dual twisted tapes (DTs) with constant twist ratio of y/W = 3.0 and delta-winged dual twisted tapes with delta-winged attack angle of α = 30° and β = 30° were carried out. Influences of the delta-winged arrangements in (1) the parallel direction (DT-PW) and (2) the counter direction (DT-CW) on the thermal performance characteristics were also described. The experimental results found that the use of the dual twisted tapes with parallel wing arrangements (DT-PW) provide the heat transfer higher than those the typical dual twisted tapes (DTs) and dual twisted tapes with counter wing arrangements (DT-CW) around 6.6-7.3% and 5.5-8%, respectively, due to stronger of dual-swirling/turbulent flow leading to better fluid mixing between the core and near tube walls while the friction factor is increasing up to 10.9 times above the plain tube. The typical dual twisted tapes (DTs), dual twisted tapes with parallel wing arrangements (DT-PW) and dual twisted tapes with counter wing arrangements (DT-CW) performs the highest thermal performance factor up to 1.2, 0.9 and 0.85 at Reynolds number of 6000. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Heat transfer and fluid flow behaviors in a five-start spiral corrugated tube(2017-08-31); ; Eiamsa-Ard, SmithThis paper presented a numerical investigation on turbulent periodic flow, heat transfer, pressure loss and thermal enhancement factor in a 3D five-start spiral corrugated tube. Air was used as the working fluids through the tube for Reynolds numbers of about 5000-20,000. In the current studied, the five-start spiral corrugated tube with six relative pitch ratios (p/D, PR=1.0, 1.5, 2.0, 2.5, 3.0 and 3.5) with constant depth ratio (e/D, DR=0.06). The numerical results reveal that the five-start spiral corrugated tube can generated a swirl flow, main swirl flow and five-secondary swirl flow. This behavior lead to the major change of temperature in transverse plane, reduced thermal layer thickness and enhanced heat transfer on the tube wall. The five-start spiral corrugated tube in range investigated provided the heat transfer rate and friction factor up to 2.02 and 6.12 times, respectively, over the straight circular tube. The thermal enhancement factor of the five-start spiral corrugated tube in the range of 0.89-1.16 where its maximum found as the optimum point is at PR=2.0. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Heat transfer enhancement in turbular heat exchanger fitted with twin twisted tape swirl generators(2017-08-31); Eiamsa-Ard, SmithAn experimental investigation was made with aim to enhance heat transfer in a double-tube heat exchanger fitted with twin twisted tapes. The effects of the twin twisted tape inserts on heat transfer rate, friction factor and thermal performance behaviors were studied in turbulent region of Reynolds number between 5000 and 15,000. The twin twisted tapes with three twist ratios (y/w = 1.5, 2.0 and 2.5) were used for generating two longitudinal swirl flows along the test section. The experimental result indicates that heat transfer rate in term of Nusselt number (Nu) and friction loss in term of friction factor (f) increase as twisted ratio (y/w) decreases. The twin twisted tapes with y/w = 1.5 yield higher Nusselt number (Nu) than the ones with y/w = 2.0 and 2.5 up to 16% and 38%, respectively which are accompanied with the higher friction factor up to 15% and 35%, respectively. Among the tested twisted tapes, the twin twisted tapes with the smallest twist ratio (y/w = 1.5) offer the maximum thermal performance factor of 1.64. In addition, the flow structure, temperature field, turbulent kinetic energy and local heat transfer coefficient in tube fitted twin twisted tapes are also presented. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Drying peppercorn characteristics in fluidized bed dryer equipped with baffle vortex generators(2018-03-26); ; Eiamsa-Ard, S.The paper deals with the characteristic study of drying peppercorn using fluidized-bed dryer fitted with baffle vortex generators. The experiments were operated at three different superficial air velocities of 1.2U<inf>mf</inf>, 1.4U<inf>mf</inf> and 1.6U<inf>mf</inf>. Experiments were operated from the initial to final moisture contents of around 12% (dry basis). During the experiments, peppercorns were sampling every 5 minutes, for moisture analysis. A typical fluidized-bed dryer was also tested under similar operating conditions for the assessment. The results indicate that the influence of superficial air velocity on drying peppercorn characteristic in the fluidized-bed dryer fitted with baffle vortex generators is more significant than that in the typical fluidized-bed dryer. It is observed that fluidized-bed dryer fitted with baffle vortex generators shows better performance in reducing moisture content with faster drying rate than the typical fluidized bed dryer especially at high superficial air velocity due to the strong longitudinal vortex which helps in improving the fluid mixing, heat and mass transfer rates. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Turbulent heat transfer enhancement in round tubes by inserting triple twisted-tapes(2015-01-01) - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Heat transfer enhancement of turbulent flow through dimpled tubes fitted with twisted tapes(2015-01-01) - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Investigation on Rice Husk Combustion in a Fluidized Bed with Longitudinal Vortex Generators(2019-05-16); Effects of wavy-ribbed surface chamber on combustion temperature/efficiency and exhaust gas behaviours in a fluidized bed combustor were investigated. In the experiments, the five wavy-rib pairs were placed at the bottom chamber for inducing longitudinal vortex flow which enhanced the fuel and fluid/combustion-air mixing in the top chamber for giving better combustion efficiency. The experiments were examined at five percent excess airs of EA = 15%, 30%, 45%, 60%, and 75% and were tested at the constant air mass flow rate of 95 kg/hr. From experimental results, it can be showed that a fluidized bed combustor with wavy-ribbed surface chamber can be promoted the high combustion efficient for all test runs especially at the percent excess airs of EA = 75%.