Jedsadaratanachai, Withada
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Preferred name
Jedsadaratanachai, Withada
Alternative Name
Jedsadaratanachai, W.
Main Affiliation
Email
withada.je@kmitl.ac.th
5 results
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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, Numerical Simulation and Optimization of Enhanced Heat Transfer in Helical Oval Tubes: Effect of Helical Oval Tube Modification, Pitch Ratio, and Depth Ratio(2018-11-26); Eiamsa-ard, SmithFlow and heat transfer behaviors in the helical oval tube, alternate-twisted-direction helical oval tube and regularly spaced helical oval tubes were numerically investigated. The helical oval tubes with eight oval tube depth ratios (0.03, 0.04, 0.05, 0.06, 0.07, 0.10, 0.15, and 0.20) and nine oval tube pitch ratios (0.6, 0.8, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, and 4.0) were examined in turbulent regime, Reynolds number ranged from 5000 to 20,000. The computational results showed that fully developed periodic flow and heat transfer in helical oval tubes commenced at around entrance length to characteristic diameter of 8–9. The decreasing depth ratio and increasing pitch ratio helped to reduce the pressure loss of the tube heat exchanger. The maximum thermal performance of 1.30 was obtained by the use of the helical oval tube with depth ratio of 0.05 and pitch ratio of 0.6 at the lowest Reynolds number of 5000. At similar conditions, typical helical oval tubes offered better heat transfer rate and thermal performance than helical oval tubes with alternate axes and regularly spaced helical oval tubes. - 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, Effect of geometrical parameters on turbulent flow and heat transfer behaviors in triple-start corrugated tubes(2018-01-01); Eiamsa-Ard, SmithComputational results of flow structure, pressure loss and heat transfer characteristics in triple-start corrugated tubes are reported. The influences of the depth ratio (DR = 0.02, 0.04, 0.06, 0.08, 0.1, 0.12, 0.14 and 0.16) and pitch ratio (PR = 0.5, 0.65, 0.75, 1.0, 1.5 and 2.0) were investigated in turbulent flow regime, Re = 5000 to 20,000. The computational results indicated that the triple-start corrugated tubes generate main swirl flow and helical swirl flow which helps to reduce the thermal boundary layer thickness and enhance the heat transfer rate. The flow and heat transfer become under fully developed periodic condition around x/D = 6.0. The friction factor monotonically increases with the rise of DR values and decrease PR values while maximum heat transfer rate is found at DR = 0.08 and PR = 0.75. Nusselt numbers and friction factors of triple-start corrugated tubes in the investigated range are found to be 0.8 to 2.31 and 1.0 to 17.14 times over those of the straight circular smooth tube, respectively. For the range studied, the triple-start corrugated tube with DR = 0.06 and PR = 0.75 offers the maximum thermal enhancement factor of 1.21 at Re = 5000. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Numerical investigation on turbulent forced convection and heat transfer characteristic in spirally semicircle-grooved tube(2016-12-01)