• Transactions of the Korean Society of Mechanical Engineers B
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• v.40 no.4
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• pp.245-253
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• 2016

The friction and deformation of a tire causes heat generation, which causes a temperature rise of the tire. This temperature rise can be a source of tire damage. The object of this study is to investigate the cooling effect of the application of a fin to the tire side to suppress the temperature rise. Eight different fin shapes were considered, and the sidewall surface temperature reduction owing to the cooling fin shape was numerically analyzed. In addition, the flow characteristics and heat transfer characteristics of the vortex of the pin rear were compared.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2079-2084
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• 2007

A small-scale thermoelectric cooling system was built in an effort to enhance the performance of the refrigeration system by utilizing the water-cooled jacket which was attached on the hot side of the thermoelectric module. Considered design parameters for the water-cooled jacket included the geometry of the flow passage inside the jacket and the flow rate of cooling water. The higher flow rate of cooling water in the jacket resulted in a better performance of the refrigeration system. The introduction of geometrical complexity of the cooling water flow passage to the cooling jacket also showed significant improvement on the performance of the thermoelectric refrigeration system such as the cooling capacity and the COP of the refrigeration system.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2714-2719
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• 2007

HANARO, an open-tank-in-pool type research reactor of 30 MWth power in Korea, has been operating normally since its initial criticality in February, 1995. For the last about ten years, A cooling tower of a secondary cooling system has been operated normally in HANARO. Last year, the cooling tower has been overhauled for preservative maintenance including fills, eliminators, wood support, water distribution system, motors, driving shafts, gear reducers, basements, blades and etc. This paper describes the results of the overhaul. As results, it is confirmed that the cooling tower maintains a good operability through a filed test. And a cooling capability will be tested when a wet bulb temperature is maintained about 28 $^{\circ}C$ in summer and the reactor is operated with the full power.

• The KSFM Journal of Fluid Machinery
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• v.15 no.4
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• pp.33-41
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• 2012

In the present work, a parametric study on double-jet film-cooling has been carried out to enhance the film-cooling effectiveness using three-dimensional Reynolds-averaged Navier-Stokes analysis. The shear stress transport turbulence model is used as the turbulence closure. The lateral ejection angles and the lateral and streamwise distance between the centers of the cooling holes are chosen as the geometric parameters. The spatially averaged film-cooling effectiveness averaged over an area of 8 hole diameters in width and 30 hole diameters in streamwise length is used to evaluate the performance of film-cooling. The parameter of the lateral distance has the largest impact on the film cooling effectiveness compared to the others. On the other hand, the parameter of streamwise distance gives the least influence on the film cooling effectiveness.

• 유체기계공업학회:학술대회논문집
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• 2002.12a
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• pp.298-303
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• 2002

Dispersion of coolant jets in a film cooling flow field is the result of a highly complex interaction between the film cooling jets and the mainstream. In order to investigate the effect of blowing ratios on the film cooling of turbine blade, cylindrical body model was used. Mainstream Reynolds number based on the cylinder diameter was $7.1{\times}10^4$. The effect of coolant flow rates was studied for blowing ratios of 0.7, 0.9, 1.2 and 1.5, respectively. The temperature distribution of the cylindrical model surface is visualized by infrared thermography (IRT). Results show that the film-cooling performance could be significantly improved by the shaped injection holes. For higher blowing ratio, the spanwise-diffused injection holes are better due to the lower momentum flux away from the wall plane at the hole exit.

• Journal of the KSME
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• v.20 no.5
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• pp.400-409
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• 1980

원자력발전소 안전성확보란 하루아침에 완성되는 것이 아니라 모든 분야의 최신기술이 종합되어 계속 수행되어야 하는 과제이다. 원자력분야에 초보자를 위해서 2절에서는 안전성의 중요성에 대하여 가상사고를 한 예로써 설명하였으며 이런 사고를 대비하여 어떤 조치가 취해지고 있는 가를 설명하기 위하여 비상노심냉각계통구조에 대해 언급하였다. 현재까지의 지식으로는 비상 노심냉각계통만 제대로 작동한다면 사고로 인한 피해는 적으리라고 예상된다. 미국 TMI사고에 서도 운전자가 오판으로 작동중인 비상노심냉각계통을 정지시키지 않았다면 사고의 피해는 크지 않았을 것으로 평가되고 있다. 3절과 4절에서는 가장 위험한 사고로 알려진 냉각재상실사고가 일어 났을 때 어떤 물리적 현상이 생기며 이런 현상을 완전히 파악하여 사고를 해석하고 사고의 영향을 줄이기 위해서는 어떤 기술적인 문제가 해결되어야 하는가를 소개하였다. 5절에서는 LOCA연구현황을 소개하였다. 학계에서 특히 열유체분야에 연구경험이 많은 사람이 조금만 관 심을 가져도 자기전공의 지식을 원자로안전성 연구에 이용하리라 기대된다.

• Proceedings of the KSME Conference
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• 2001.11b
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• pp.940-945
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• 2001

Gasoline engine manufacturers are currently considering designs that will result in low combustion air temperature for improvement of fuel consumption and emission levels. There are a variety of cooling systems that can be used to accomplish this goal. Cooling is therefore normally achieved through a balance of ram and fan action. This paper studies the various systems and compare the cooling performance for several conditions, based on a automotive engine. An experimental analysis was developed to predict the interaction of the fan system and the heat exchangers of the engine cooling system. The local temperature induced by the fan on the cooling system is measured. These experimental result were accomplished using airflow management techniques.

• Journal of Power System Engineering
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• v.10 no.4
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• pp.11-16
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• 2006

This research is to verify the cooling effect of the acting surface on the rotary motor using heat pipe and conventional cooling fan. In order to show the cooling performance of the rotary motor and heat pipe with the fin-typed heat sink, the surface temperature of the motor and condenser was measured in real time. The experiments were also conducted as for not only cooling device installed with heat pipe only, but with heat pipe and conventional cooling fan simultaneously. The present experiment reveals that the cooling combination of the heat pipe and cooling fan is far superior to the conventional cooling device for the driving motor such as the fin-typed heat sink. When the driving voltage of 20V and 14V were supplied to the driving motor, the cooling performance of the rotary motor with heat pipe was 170% and 500%, respectively better than that without heat pipe on steady state condition.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.9
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• pp.743-749
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• 2015

The purpose of this study is to predict the performance of an indirect evaporative cooling system, and to evaluate its energy saving effect when applied to the exhaust heat recovery system of an air-handling unit. We derive the performance correlation of the indirect evaporative cooling system using a plastic heat exchanger based on experimental data obtained in various conditions. We predict the variations in the performance of the system for various return and outdoor air conditioning systems using the obtained correlation. We also analyze the energy saving of the system realized by the exhaust heat recovery using the typical meteorological data for several cities in Korea. The average utilization rate of the sensible cooling system for the exhaust heat recovery is 44.3% during summer, while that of the evaporative cooling system is 96.7%. The energy saving of the evaporative cooling system is much higher compared to the sensible cooling system, and was about 3.89 times the value obtained in Seoul.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.41 no.10
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• pp.693-698
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• 2017

The 18650 battery cell is known to be reliable and cost effective, but it has a design limitation and low electric capacity compared to pouch-type cells. Because its economy is superior, an 18650-cell-type battery pack is chosen. A reliable temperature is very important in automobile battery packs. Therefore, in this study, the temperature stability of the battery pack is predicted using CFD simulation. Following 3C discharge tests, the results for the heat generation of the battery cell are compared to the simulation results. Based on these results, a natural convection condition, forced convection condition, direct cell-cooling condition, cooling condition on the upper and lower surfaces of the battery pack, and cooling condition using air channels are all simulated. The results indicate that the efficiency and the performance of the air-channel-type cooling system is good.