• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2005.11a
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• pp.213-219
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• 2005

Small liquid rocket engine (SLRE) with calorimeter were developed and tested to evaluate cooling characteristics in the liquid rocket engine. Therefore, cooling performance analysis was performed to predict the heat transfer coefficient on gas side wall in 10 calorimeter channel. A heat transfer empirical formula was determined by results of firing test and computational simulation.

• Journal of the Korean Society of Propulsion Engineers
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• v.8 no.1
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• pp.81-84
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• 2004

A water-cooled calorimeter chamber with 8 cooling channels based on KSR-III sub-scale chamber has been designed and manufactured. One dimensional empirical correlation has been used at the design stage and full three-dimensional CFD analysis has been conducted to confirm the cooling condition for hot fire test is safe. Predicted heat flux is accurate around the nozzle throat when the thermal resistance of carbon deposit is considered. However relatively large difference is observed in chamber part.

• Journal of computational fluids engineering
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• v.8 no.3
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• pp.56-65
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• 2003

A numerical procedure for analyzing the heat transfer in a regenerative cooling passage of liquid rocket has been developed. The thermal analysis is based on the numerical model of Naraghi〔1〕. The thermodynamic and transport properties of the combustion gases are evaluated using the chemical equilibrium composition. The pressure and heat flux obtained by the isentropic relation are in good agreement with the result of Navier-Stokes equations. The effect of design parameters on heat transfer is addressed for the pressure loss and temperature variation. Also, their constraints in designing the cooling passage are recommended. Finally, in a heated rectangular duct, the effects of secondary flow on heat transfer are scrutinized by the nonlinear k- e -fu of Park et at.〔2〕.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1760-1761
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• 2011

원자력발전기술원은 발전정지 관련계통 제어케비넷 내에 장착된 제어용 기기들의 다중화 설계변경 활동을 지원하고 관련 기기의 배선상태 등의 육안점검을 통해 취약성 여부를 최종 확인하기 위하여 국내 Westinghouse형 원전 계측제어 케비넷 점검을 수행하였다. 또한 관련 설계변경에 대한 신뢰도평가 기술지원도 함께 수행하여 해당 설계변경이 설비의 신뢰도 향상에 효과가 있는지를 정량적으로 평가하고자 하였다. 이에 따라 원자로냉각재펌프(RCP, Reactor Coolant Pump) 제어 채널의 다중화 개선에 대하여 설계변경 전후의 기기 배열 변화에 따른 계통 신뢰도 변화를 대표유형 기기의 고장률에 근거하여 분석하였다. 고장수목을 이용하여 설계변경 전후의 RCP 고장정지로 인한 발전정지를 유발하는 고장조합을 도출하고, 고장정지 확률 변화를 정량화 하였다. 또한 기기 보호 측면에서 펌프 보호를 위한 신호를 출력하지 못하는 경우를 정량화하여 이를 비교하였다.

• Transactions of the Korean hydrogen and new energy society
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• v.26 no.2
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• pp.127-135
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• 2015

High-Temperautre Polymer Electrolyte Membrane Fuel Cell (HT-PEMFC) with phosphoric acid-doped polybenzimidazole (PBI) membrane has high power density because of high operating temperature from 100 to $200^{\circ}C$. In fuel cell stack, heat is generated by electrochemical reaction and high operating temperature makes a lot of heat. This heat is caouse of durability and performance decrease about stack. For these reasons, heat management is important in HT-PEMFC. So, we developed HT-PEMFC model and study heat flow in HT-PEMFC stack. In this study, we placed coolant plate number per cell number ratio as variable and analysed heat flow distribution in stack.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.11
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• pp.1267-1273
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• 2009

Hot press forming can produce high-strength components by rapidly cooling between closed punch and die after hot forming using quenchable boron steel austenized in a furnace. In the hot press forming process, the cooling rate is influenced by the size, position and arrangement of the cooling channel and the file condition of cooling water in the die. Also, mechanical properties of the final components and operation time are related to cooling rate. Therefore, the design of optimized cooling channel is one of the most important works. In this paper, the effect of position and size of the cooling channel on the cooling rate was investigated by using design of experiment and FE analysis in hot press bending process. Therefore the optimum cooling channel ratio was presented in the HPB.

• Journal of Power System Engineering
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• v.13 no.1
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• pp.5-12
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• 2009

The present work aims to estimate channel, shell, tube and tube sheet stresses of shell and tube oil cooler stemmed from various parameters. These parameters involve size, thickness and dimension of shell and tube oil cooler, including fluid temperature. The main purpose of the present work is to ensure safety of design products and also develop new products rapidly. For stress evaluation of oil coolers, first of all, the maximum pressure on the shell-side and on the tube side is fixed with 3.1MPa and 1.5MPa, respectively. Secondly, the pressure on each side varies from 2MPa to 3.1MPa on the shell side and tram 0.6MPa to 2MPa on the tube side. Various parameters under these conditions are employed to estimate design stresses on each side of oil cooler. These basic information related to stresses will be useful for a designer or manufacturer of an oil cooler.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.31-36
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• 2003

Recently, the power consumption and heat generation in an electronic equipment increase as the components are miniaturized and the computing speed becomes faster. Effective cooling method is required to ensure the guaranteed performance and reliable operation of the electronic devices. The aim of the present study is to investigate the cooling characteristics of a pin-fin heat exchanger as a candidate for cooling system of the electronic devices. Various configuration of the pin-fin array is selected in order to find out the effect of spacing and diameter of the pin-fin on the heat transfer characteristics. The results are compared with the experimental data or correlations of several researchers for the channel flow with pin-fin arrays.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.15 no.8
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• pp.667-673
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• 2003

Recent trends in the electronic equipment indicate that the power consumption and heat generation in a chip increase as the components are miniaturized and the computing speed becomes faster. Suitable heat dissipation is required to ensure the guaranteed performance and reliable operation of the electronic devices. The aim of the present study is to investigate the forced-convective thermal-hydraulic characteristics of a pin-fin heat exchanger as a candidate for cooling system of the electronic devices. The influence of the structure of the pin-fin assembly on heat transfer is investigated by porous medium model. The results are compared with the experimental data or correlations of several researchers for the heat transfer coefficients for the channel flow with pin-fin arrays. Finally, the effects of design parameters such as the pin-fin diameter and the spacing are examined.

• Nuclear Engineering and Technology
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• v.26 no.4
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• pp.555-561
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• 1994

The program of performing a fast and automatic analysis of gamma ray spectra obtained by a Multi-Channel Analyzer (MCA) is developed for the surveillance of the nuclear fuel integrity. The integrity of the nuclear fuel is confirmed by the measurement of the radiation level of the reactor coolant through the real time monitoring and the periodic sampling analysis. In Yonggwang nuclear power plane 3 and 4, the Process Radiation Monitoring System (PRMS), which is a real time monitoring system, provides a measure of the fuel integrity. Currently, its spectrometer channel can identify only one radionuclide at a time since the signal processing unit of the spectrometer channel is a Single Channel Analyzer (SCA). To improve the PRMS, it is necessary to substitute the MCA for the SCA The program is operated in a real time mode and an on-demand mode, and automatically performed for all procedures. The test results by using the National Bureau of Standards (NBS) mixed standard source are in good agreement with those from Canberra System 100 which is a commercial MCA Consequently, the developed program seems to be employed for automatic monitoring of gamma rays in nuclear power plants.