Promvonge, Pongjet
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Preferred name
Promvonge, Pongjet
Alternative Name
Promvonge, P.
Main Affiliation
Email
pongjet.pr@kmitl.ac.th
35 results
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Item type:Publication, Numerical study on heat transfer of turbulent channel flow over periodic grooves(2008-08-01) - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Numerical simulation of flow field and temperature separation in a vortex tube(2008-01-01) - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Experimental study of combustion characteristics in a rice husk fired vortex combustor(2001-12-01); Silapabanleng, KulthornThis paper presents the study of combustion characteristics of rice husk fuel in an annular vortex combustor (VC). The temperature distributions for selected locations inside the combustor and the fly ash and smoke from its flue gas were measured and observed respectively. Measurements were made by setting a constant mass flow rate of rice husk to be 0.2 kg/min and by varying the equivalence ratio, φ, to be 0.8, 1.0 and 1.2. To study the effect of feeding secondary air on flame stability, three values of the ratio of volumetric flow rates of the secondary air to the total air, (λ), were used and set to be 0.0, 0.2 and 0.4. The experiment shows the maximum temperature of about 1000° C in the upper chamber with less smoke of flue gas. Besides, emissions and the sizes of flyash particles from the exhaust stack can be controlled by the flow rate ratios of the secondary air to the total air, λ The VC shows an excellent performance, low emissions, high stabilization and ease of operation in firing the fine rice husk. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Turbulent convection in round tube equipped with propeller type swirl generators(2009-04-01) - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Heat transfer characteristics in a tube fitted with helical screw-tape with/without core-rod inserts(2007-02-01) - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Thermal performance in circular tube fitted with coiled square wires(2008-05-01)The effects of wires with square cross section forming a coil used as a turbulator on the heat transfer and turbulent flow friction characteristics in a uniform heat flux, circular tube are experimentally investigated in the present work. The experiments are performed for flows with Reynolds numbers ranging from 5000 to 25,000. Two different spring coiled wire pitches are introduced. The results are also compared with those obtained from using a typical coiled circular wire, apart from the smooth tube. The experimental results reveal that the use of coiled square wire turbulators leads to a considerable increase in heat transfer and friction loss over those of a smooth wall tube. The Nusselt number increases with the rise of Reynolds number and the reduction of pitch for both circular and square wire coils. The coiled square wire provides higher heat transfer than the circular one under the same conditions. Also, performance evaluation criteria to assess the real benefits in using both coil wires of the enhanced tube are determined. © 2007 Elsevier Ltd. All rights reserved. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Thermal enhancement in a round tube with snail entry and coiled-wire inserts(2008-05-01)Influences of the insertion of coiled wires in conjunction with a snail-type swirl generator mounted at the tube entrance on heat transfer and turbulent flow friction characteristics in a uniform heat-flux, circular tube are experimentally investigated. In the present work, the coiled wire used as a turbulator is placed inside the test tube using air as the test fluid while the snail is employed to create a decaying swirl flow at the tube inlet. The effects of the snail entry and insertion of two different wire-sections of coils: square and circular, with a fixed pitch ratio on heat transfer rate in the tube are examined for the Reynolds number ranging from 5000 to 25,000. The experimental results are compared with those obtained from using coiled wire/snail entry alone, apart from the smooth tube. The results reveal that the presence of coil-wires together with the snail leads to a considerable increase in heat transfer and friction loss over the smooth tube. The snail entry with the coiled square-wire provides higher heat transfer rate than that with the circular one under the same conditions. Also, performance evaluation criteria to assess the real benefits in using both the coil-wire and the snail entry of the enhanced tube are determined. © 2008 Elsevier B.V. All rights reserved. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Turbulent flow heat transfer and pressure loss in a double pipe heat exchanger with louvered strip inserts(2008-02-01); In the present work, heat transfer and friction characteristics were experimentally investigated, employing louvered strips inserted in a concentric tube heat exchanger. The louvered strip was inserted into the tube to generate turbulent flow which helped to increase the heat transfer rate of the tube. The flow rate of the tube was in a range of Reynolds number between 6000 and 42,000. The turbulent flow devices were consisted of (1) the louvered strips with forward or backward arrangements, and (2) the louvered strip with various inclined angles (θ = 15°, 25° and 30°), inserted in the inner tube of the heat exchanger. In the experiment, hot water was flowed through the inner tube whereas cold water was flowed in the annulus. The experimental data obtained were compared with those from plain tubes of published data. Experimental results confirmed that the use of louvered strips leads to a higher heat transfer rate over the plain tube. The increases in average Nusselt number and friction loss for the inclined forward louvered strip were 284% and 413% while those for the backward louvered strip were 263% and 233% over the plain tube, respectively. In addition, the use of the louvered strip with backward arrangement leads to better overall enhancement ratio than that with forward arrangement around 9% to 24%. © 2007 Elsevier Ltd. All rights reserved. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Heat transfer in a circular tube fitted with free-spacing snail entry and conical-nozzle turbulators(2007-08-01); Eiamsa-ard, S.The paper presents the effect of a free-spacing snail entry together with conical-nozzle turbulators on turbulent heat transfer and friction characteristics in a uniform heat-flux tube. The insertions of the conical or converging nozzle (C-nozzle) with different pitch ratios (PR) in common with the free-space snail entry are examined in a Reynolds number range from 8000 to 18000. A substantial augmentation of heat transfer for using the C-nozzles and snail entrance is expected by a strong influence from nozzle-induced reverse/re-circulation motion and snail-produced vortex/swirl motion for high Reynolds number. The experimental result shows a considerable increase in friction factor and heat transfer over the plain tube under the same operation conditions. Over the range investigated, the Nusselt numbers for employing both the enhancement devices with PR = 2.0, 4.0 and 7.0 are found to be higher than that for the plain tube around 315%, 300% and 285% respectively. The results obtained are correlated in the form of Nusselt number as a function of Reynolds number, Prandtl number and pitch ratio. For performance comparison at equal pumping power, both the enhancement devices with the smallest pitch ratio perform the best, especially at low Reynolds number. The present results are also compared with correlations obtained from similar enhancement devices but without free-spacing entry. © 2007 Elsevier Ltd. All rights reserved. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Numerical investigations of compressible flow and energy separation in a counter-flow vortex(2007-01-01)