• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.11a
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• pp.169-174
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• 2006

This paper is related to a design of high pressure sub-scale combustor with regenerative reeling. As a previous step for the evaluation of thermal heat flux, a similar combustor with cooling water was manufactured. Design conditions with high combustion efficiency and cooling performance were verified through the hot firing tests of the water-cooled high pressure combustor. Finally the regeneratively cooled high pressure combustor has been designed based on these data. After manufacturing it, its practical utility will be tested and verified through hot firing tests.

• Aerospace Engineering and Technology
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• v.3 no.1
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• pp.197-204
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• 2004

A design of regenerative cooling system of 30 ton level thrust combustion chamber for ground test has been performed. The 1-D design code has been validated by comparing with the heat flux of the NAL calorimeter for high chamber pressure and water-cooling performance of the ECC engine of MOBIS. The present design code has been confirmed to predict accurately the heat flux and water-cooling performance for high chamber pressure condition. The maximum hot-gas-side wall temperature is predicted to be about 720 K without thermal barrier coating and the coolant-side wall temperature is less than the coking temperature of RP-1. The coolant temperature rises nearly 100 K with thermal barrier coating when Jet-A1 is used as coolant.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.10a
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• pp.189-192
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• 2004

Test Facility for hot firing test of small size liquid rocket engine has been developed to research the cooing characteristics of kerosene for cylinder part especially. Propellants for the tests are kerosene and liquid oxygen as fuel and oxidizer respectively and they are fed by gaseous nitrogen. The engine components used hot firing test except for cylinder are cooled by tap-water. Valves for supply of propellants and coolants are controlled by pneumatically. System control and data recording are conducted automatically.

• The Journal of Korean Academy of Prosthodontics
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• v.50 no.1
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• pp.29-35
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• 2012

Purpose: The purpose of this study was to analyze temperature change along the implant-bone interface induced by grinding the occlusal surface of implant gold prosthesis and to compare the temperature generated by grinding of prosthesis with different cooling methods. Materials and methods: The experimental gold prostheses were fabricated with dental gold alloy and castable abutment. The prostheses had 3 cylindrical protrusions on the occlusal surface with 1mm in height. Temperature was measured using 16 thermocouple wires attached to the implant fixture surface and the fixture was embedded in an acrylic resin block inside the $37^{\circ}C$ water bath. Cylinders were grinded for a period of 30 second with a low-speed handpiece with green stone point. One cylindrical protrusion was grinded without cooling, the second one was grinded with air blow, and the third one was grinded with water-spray. Results: The mean maximum temperature was measured more than $47^{\circ}C$ of the implant and the maximum temperature was measured at the cervical portion of the implant in the group without cooling. There was statistically significant difference between the group without cooling and the groups with cooling (P<.05). However, there was no significant difference at all portion of implant in the groups with cooling (P>.05). Conclusion: The results of this study support that the grinding of implant gold prosthesis without cooling may damage the peri-implant tissue. The continuous use of air blow and water-spray adjacent to prosthesis during the grinding of implant gold prosthesis may prove to be beneficial for cooling of the implant.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2000.05a
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• pp.59-60
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• 2000

냉각탑(Cooling Tower)은 가열된 물을 냉각, 재순환시켜 냉각수로 재사용하는 일종의 열교환장치로서, 빌딩, 호텔, 병원, 백화점 및 극장 등과 같은 대형건물의 냉동공조시스템에 필수적으로 사용되는 것은 물론이고, 주물공장, 냉동공장 및 석유화학플랜트 등의 중화학공장과 같은 대형공장에도 중요한 Utility설비 중의 하나이다. 이 냉각탑은 각 구성품의 재질은 주로 FRP와 철구조물로 되어있고, 대기 중에서 물 또는 수증기와 직접 접촉하므로 강한 부식성 환경에 노출되어 있다.(중략)

• Proceedings of the Korean Nuclear Society Conference
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• 1996.11a
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• pp.103-109
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• 1996

고리 원자력 1호기 14주기(‘95년도) 운전기간 중 증기발생기 세관 열전달 용량 저하로 전출력 운전 기간동안 정격출력보다 15% 감발 운전한 경험이 있었는데, 이 기간중 냉각재내 방사성 부식생성물(CRUD) 농도가 약 80% 감소됨을 발견하였다. 이때 출력감소 비율보다 많은 CRUD 감소현상 규명을 위해 냉각재 수질관리인자와 EPRI 피복재 부식모델인 PFCC코드를 사용한 피 복재 산화물 두께변화 등을 비교한 결과, 운전중 용출되는 방사성 부식생성물은 핵연료 표면의 피복재 산화물에 흡착된 Co핵종이 피복재 산화물 이탈시 함께 거동하는 것으로 확인되었으며, 피복재 산화물 이탈은 산화막 두께 및 열유속에 주로 의존함이 밝혀졌다. 따라서 냉각재내에서 방사성 부식 생성물의 생성률 저감을 위해서는 정상운전시 핵연료 표면의 산화막 증가를 억제할 수 있는 수질 조건을 도출하고 그에따른 운전을 통해 원전 작업자의 방사선 피폭량 저감 및 방사성폐기물의 발생을 줄일 수 있을 것으로 여겨진다.

• Aerospace Engineering and Technology
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• v.10 no.1
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• pp.129-135
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• 2011

A study of efficient plume cooling by core water injection type was performed by computational fluid dynamics. A side injection type is well known, on the contrary, a core injection type is not well known. In order to figure out the characteristics of core injection type, several calculations were performed by computational fluid dynamics along various mass flow rates and locations of water injection. On the basis of analysis it was the adequate cooling condition that water mass flow rate to total mass flow rate was two times at least and location of water injections was L/De=1.2.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.1
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• pp.37-43
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• 2015

Evaporative cooling is a very effective way for exhaust heat recovery that uses both latent heat and sensible heat. This study investigated the performance of a heat recovery system using evaporative cooling. The experimental apparatus comprised a plastic heat exchanger, a water spray nozzle, an air blowing fan, a water circulation pump, and measuring sensors for the temperature, humidity, and flow rate. The effectiveness of the sensible heat recovery without evaporation was measured and compared with that of the total heat recovery with evaporation. The effectiveness of the sensible and total heat recoveries decreased as the air flow rate increased, and a much higher effectiveness was obtained with the counterflow arrangement in both cases. For total heat recovery, the effectiveness increased with the water flow rate, and the parallel flow arrangement was found to be more sensitive to the water flow rate than the counterflow arrangement.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.3
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• pp.78-85
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• 2005

The purpose of the study was to establish the design procedure and develop the program for designing regenerative cooling system. To obtain the design parameter necessary for the realization of regenerative cooling system, water-cooled regenerative cooling system was designed from suggested procedure. To compare experimental results with a present method of analytically predicting the heat transfer loads, $250kg_{f}$ experimental LRE with water-cooled regenerative cooling system was investigated. Based on the investigation, the good correction between the predicted and measured data was verified. Developed design program can be used to designing Kerosene- cooled regenerative cooling system. The basic experimental data and correlations obtained in this study for 250kgf experimental LRE with water-cooled regenerative cooling system can be directly applicable to the real LRE.

• Journal of the Korean Society of Propulsion Engineers
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• v.19 no.1
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• pp.61-67
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• 2015

The cooling of hot exhaust gas is an important issue for the construction of combustor test facility. Water spray is an effective method for exhaust gas cooling due to its large latent heat in process of evaporation. In this study, 1-D analysis has been performed based on continuity, energy conservation, and saturated vapor property to understand water spray cooling of combustion gas. In the exhaust duct of combustor test facility, the injected water decreases combustion gas temperature, and evaporates in the combustion gas. However, some of the injected water is collected in the sump due to condensation. The evaporation of water helps combustion gas cooling, but causes pressure increase inside the exhaust duct due to increase of vapor pressure. These phenomena has been analyzed by 1-D modeling in this study. From 1-D analysis, the adequate mass flow rate of water spray to cool combustion gas and to avoid excessive pressure rise inside the exhaust duct has been decided.