• Proceedings of the KSME Conference
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• 2004.11a
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• pp.1046-1051
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• 2004

A plate-fin-tube heat exchanger used for a $SF_{6}$ gas-insulated transformer is extremely important since the dissipation of the heat generated from inside coils has a significant effect on the performance as well as the durability of the transformer. The heat exchanger consists of corrugated plate fins and staggered array tube bundles for coolant. In order to find out heat transfer and pressure drop characteristics, series of numerical analyses for plate fins with enhanced surface geometries were conducted. Based on the results of the numerical analyses, an improved model of the plate fin has been proposed.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2023-2028
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• 2008

In present study, the flow field near the fin surface of plate fin - oval tube heat exchanger with delta wing vortex generator was numerically analyzed. As results, the well developed vortex behind delta wing was observed. These vortex can improve heat transfer fin surface behind delta wing vortex generators.

• Journal of the Korean Society of Visualization
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• v.10 no.3
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• pp.37-41
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• 2012

Plate-fin heat exchanger is a kind of compact heat exchangers with a good performance in heat transfer. It is widely used in various engineering fields such as aerospace, chemical and biomedical industries. Quantitative and qualitative flow visualization study were performed using the water model of commercial plate-fin heat exchanger with header angles of $30^{\circ}$. The Reynolds number was 100. Conventional digital particle image velocimetry was used to measure the instantaneous velocity fields of the header region and the flow visualization using dye injection and hydrogen bubble method were applied to capture the qualitative flow characteristics. The results showed the existence of separation flow region at the junction area and the bottom wall of the exit region.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.3
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• pp.269-278
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• 2011

We investigate the heat-transfer and pressure-drop characteristics of fin-and-tube heat exchangers with a copper plate or copper spiral fins. Twenty-four samples with different fin pitches and tube rows were tested. For both configurations, the effect of the fin pitch on the j factor is negligible, and the f factor increases with the fin pitch. The effect of the tube row depends on the configuration. For plate fin-and-tube heat exchangers, the j factor decreases as the row number increases; the reverse is true for spiral exchangers. We explain this by considering the flow pattern. The j factor for plate fin-and-tube heat exchangers is larger than that for spiral exchangers, and the difference decreases as the row number increases. The f factor of the plate fin-and-tube heat exchanger is also larger. We compare our results with existing predictions of correlations.

• Proceedings of the KSME Conference
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• 2005.11a
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• pp.33.1-33.1
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• 2005

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.5
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• pp.515-522
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• 2010

The objective of this study is to investigate the air-side heat transfer characteristics of a spirally-coiled circular fin-tube heat exchanger for various geometric parameters under non-frosting conditions. The heat transfer characteristics of the heat exchanger were analyzed with respect to heat exchanger geometries, and then, the characteristics were compared with those of rectangular-plate fin-tube heat exchangers with discrete fins. The heat transfer coefficient increased with a decrease in the number of tube rows and an increase in the fin pitch. The optimum length of the L-foot was 2.7 mm. In addition, the heat transfer rate increased with a decrease in the tube pitch and the tube thickness. The heat transfer coefficient of the spirally-coiled circular fin-tube heat exchanger was 24.3% higher than that of the rectangular-plate fin-tube heat exchanger.

• 한국전산유체공학회:학술대회논문집
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• 2011.05a
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• pp.141-147
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• 2011

A two-phase numerical model for plate-fin heat exchangers with plain fins and wave fins is studied incorporating the thermodynamic properties and the characteristics of fluid flow. The numerical simulations for the two fins in cryogenic conditions are earned out by employing a homogenous two-phase flow model with the CFD code ANSYS CFX. The heat transfer coefficients and the friction factor for nitrogen saturated vapor condensation process inside two types of plate fin heat exchanger are evaluated including the effects of saturation temperature (pressure), mass flow rate and inlet vapor quantity. The convective heat transfer coefficients and friction factors will be used for design of plate-fin type heat exchangers operating under cryogenic conditions.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.22 no.3
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• pp.171-179
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• 2010

Thermal performance of louver fin and plate fin in a thermoelectric cooling system with a duct-flow type fan arrangement is analytically evaluated. The thermoelectric cooling system consists of a thermoelectric module and two heat exchanger fins. The analytic results show that the optimized louver fin has lower thermal resistance than plate fin. The COP and heat absorbed rate of the thermoelectric cooling system with optimized louver fins are 10.3% and 5.8% higher than optimized plate fins, respectively.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.2
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• pp.205-215
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• 2001

An experimental study has been performed to investigate the heat transfer characteristics of fin and tube heat exchanger. The existing transient and steady methods are very difficult to apply for the measurements of heat transfer coefficients of a thin heat transfer model. In this study the lumped capacitance method was adopted. The heat transfer coefficients were measured by using the lumped capacitance method based on the liquid crystal thermography. The method is validated through impinging jet and flat plate flow experiments. The two experiments showed that the results of the lumped capacitance method with polycarbonate model showed very good agreements with those of the transient method with acryl model. The lumped capacitance method showed similar results regardless of the thickness of polycarbonate model. The method was also applied for the heat transfer coefficient measurements of a fin and tube heat exchanger. The quantitative heat transfer coefficients of the plate fin were successfully obtained. As the frontal velocity increased, the heat transfer coefficients were increased, but the color-band shape showed similar patterns regardless of frontal velocity.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.2 no.2
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• pp.85-98
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• 1990

Method of optimum design of a compact sensible plate-fin heat exchanger for the heat recovery of exhaust gas from the air conditioning space was developed in consideration of the econamics of investment cost and profit according to the installation of heat exchanges. In the counterflow heat exchanger, the frontal area was fixed and the length of heat exchanger was optimized in order to maximize the net gain according to the setting of the heat exchanger. In the cross flow heat exchanger, the size of the exchanger was also optimized to maximize the net gain.