• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.194-198
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• 2006

In this study, numerical modeling was performed to analyze air flow including radiation heat transfer inside a small chamber. Characteristics of heat transfer between source plate and target through glass are investigated for various surface temperature of heat source plate with buoyancy effect due to gravity force. Conduction heat transfer through the glass is considered and heat source plate is assumed to be a black body. Target surface temperature is largely affected by the radiation heat transfer. It can also be seen that as the source temperature increases target surface is dominated by radiation rather than convective heat transfer by air.

• Journal of the Korean Society of Industry Convergence
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• v.26 no.2_2
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• pp.255-263
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• 2023

The shell and tube-type heat exchangers have been frequently used in many industrial field because of its simple structure and wide operation conditions and so on. The purpose of this study is to investigate the flow characteristics in single shell of shell and tube-type heat exchanger according to velocity and temperature of hot air released from heat exchanger simulator through numerical analysis. As the results, the temperature was decreased in almost quadratic curve from top to bottom in single shell of the shell and tube-type heat exchanger. Further the changes of pressure and velocity in outlet according to change of inlet temperature were not observed. The cost for operating the shell and tube-type heat exchanger should be compared the supply cost of hot air with that of velocity in order to make a economic decision.

• Transactions of the Society of Information Storage Systems
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• v.11 no.1
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• pp.16-21
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• 2015

An archive system is designed to store data for a long time without loss. However, many important factors such as temperature, dust, vibration, and humidity must be considered to design a successful archive system. Read/write devices, for example optical disk drives(ODDs), in an archive system generate heat while they are in operation. Fans are usually used to remove heat but the air flow accompanies dust into the system result in system failure. In this study, an archive system with six ODDs is chosen as an analysis model and flow together with temperature distributions are computed using a CFD simulation package. Flow analysis is focused on four cooling fans at the rear panel and temperature distribution is studied for various cases of fan operation. From the temperature point of view, fans give significant effects on $4^{th}$ to $6^{th}$ ODDs compared to the $1^{st}$ to $3^{rd}$ ODDs. Also, it is noticed which fan is the most important as far as cooling is concerned.

• Journal of Power System Engineering
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• v.16 no.2
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• pp.17-23
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• 2012

The steady three-dimensional computational thermal flow analysis using standard k-${\varepsilon}$ turbulence model was carried out to investigate the heat transfer characteristics of a cabin cooler for a commercial vehicle. The heat exchanging method of this cabin cooler is to use the cooling effect of a thermoelectric module. In view of the results so far achieved, the air system resistance of a cabin cooler is about 12.4 Pa as a static pressure, and then the operating point of a cross-flow fan considering in this study is formed in the comparatively low flowrate region. The air temperature difference obtained from the cold part of an thermoelectric module is about $26^{\circ}C$, and the cooling water temperature difference obtained from the hot part of an thermoelectric module is about $3.5^{\circ}C$.

• Journal of computational fluids engineering
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• v.12 no.3
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• pp.47-54
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• 2007

A periodic CFD approach for the performance analysis of compact high temperature heat exchangers is introduced and applied to selected benchmark problems, which are a fully developed 2D laminar heat transfer, a conjugate heat transfer between parallel plates which have exact solutions, and a heat transfer in a real high temperature heat exchanger module. The results for the 2D laminar heat transfer and the 2D conjugate heat transfer showed a very good agreement with the exact solutions. For the high temperature heat exchanger module, the pressure drops were predicted well but some difference was observed in the temperature parameters when compared to the full channel CFD analysis due to assumptions introduced into the periodic approach. Considering its assumptions and simplicities, however, the results showed that the periodic approach provides physically reasonable results and it is sufficient to predict the performance of a heat exchanger within an engineering margin and with much less CPU time than the case of a full channel analysis.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.4
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• pp.1503-1510
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• 2012

In this research, various cases of centrifugal impeller for HVAC system have been numerically analyzed by changing center angle of blades and length of outlet. Commercial CFD code, FLUENT has been used to calculate velocity, pressure, turbulence intensity, and temperature that can lead numerous results. Regardless of warming up, when the heater power level was increased, the temperature inside surrounding impeller also increased due to flowing outer air, but the temperature decreased because of flowing inner air. Consequently, the variation of central angle of blades and length of outlet led difference of velocity and flow rate which can reduce $CO_2$ in gas emission.

• The Transactions of the Korean Institute of Power Electronics
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• v.3 no.3
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• pp.246-255
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• 1998

The cable cooling through installing the cooling pipe along the transmission cable becomes universal in foreign leading countries, especially in Japan, and, there are so many study results inside and outside of the country. However, the remarkable study result for cooling method of cable splice part is not achieved in spite of its importance. This paper is, therefore, carrys out detailed heat transfer analysis of existing 154kV underground cable-splice, depending on the insulation thickness variation when it is installed in manhole of tunnel whose temperature is maintained as $10^{\circ}C$ using refrigerator. This paper study also the cooling method of underground cable splice based on this result.

• Transactions of the Korean Society of Automotive Engineers
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• v.20 no.5
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• pp.95-101
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• 2012

An electric water pump for engine cooling system has an advantage which particularly in the cold start, the use of the electric water pump saves fuel and leads to a corresponding reduction in emissions. The canned type electric water pump without mechanical sealing elements was selected to meet the requirements for operational reliability and life. However, the electric water pump for internal combustion engine generates much more heat loss than for hybrid electric vehicle since it is operated by the electric power of high current and low voltage. In this study, the fluid flow and thermal characteristics of the canned type electric water pump as an inverter integrated water pump has been investigated under the effects of heat generation. The analysis conditions such as outdoor air temperature of $125^{\circ}C$, water pump speed of 6000 rpm, coolant temperature of $106^{\circ}C$ and coolant flow rate of 120 L/min was used as a standard condition. Therefore, flow fields and temperature distribution inside the water pump were obtained. Also, we checked the feasibility of the canned type for the electric water pump in comparison with the mechanical seal type.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.6
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• pp.1609-1620
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• 1993

A Study on the trombe wall system, a kind of passive solar systems, has been performed numerically. The system is treated as a two-dimensional steady turbulent natural convection including constant heat source per unit area. The numerical code, "PHOENICS, " was employed to analyze this conduction-convection conjugated heat transfer. The general mode of the flow field was examined, and the exchange of mass between two recirculating flows is found to be the major mechanism of the heat transfer. It is shown that the performance is affected by the changes in the geometrical factors-the thickness of the wall, the width between the windowand the wall, and size of the vents. Further analysis has been performed to show the optimal geometry with regard to the last two factors.o factors.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2448-2453
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• 2008

The present study numerically investigates the flow and heat transfer characteristics of rib-induced secondary flow in a cooling channel with staggered V-shaped ribs, extruded on both walls. The rib-height-to-hydraulic diameter ration (h/$D_h$) is 0.17; the rib pitch-to-height ratio (p/h) equals 2.8; the Reynolds number is 50,000. Shear stress transport (SST) turbulence model is used as a turbulence closure. The present results are compared with those for a continuous V-shaped rib. Computational results show that, for average heat transfer rate the staggered V-shaped rib gives about 2.5 times higher values than the continuous V-shaped rib, while, for the streamwise pressure drop the former gives about 5 times higher values than the latter. Consequently, for the thermal performances, based on the equal pumping power condition, the staggered one gives about 2 times higher values than the continuous one. Also, for the staggered V-shaped rib, complex secondary flow patterns are generated in the duct due to the snaking flow in the streamwise direction, and more uniform heat transfer distributions are obtained.