• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.988-991
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• 2011

This study aims to analyze the effects of design parameters of the slotted cooling liner for air-breathing propulsion system. The three kinds of design parameters of the slotted cooling liner were selected and were investigated effect on the cooling performance of the slotted cooling liner. In this paper calculation results for inner wall temperature of cooling liner from heat transfer calculations were presented.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.11a
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• pp.170-173
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• 2007

Cooling characteristics of a liner were investigated by a film cooling method using a gas nitrogen in a rocket engine. High temperature gas of this test was made by mixing liquid nitrogen with combustion gas of a liquid rocket. A supply system of gas nitrogen was additionally constructed to the existing test facility of liquid rocket engine, and a new test section consisted of a liner and a gas injection ring was manufactured. A 10 second firing test for finding cooling characteristics of the liner was successfully conducted and liner surface temperatures and hot gas temperature was obtained.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.642-647
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• 2010

Film cooling is used to protect thermally the inner wall of combustion chamber exposed to hot gas in air-breathing propulsion system and specially film cooling using slotted cooling liner has been investigated to improve the cooling characteristics for a long time. In this paper results from gas dynamic and heat transfer calculations were presented in the combustion area and cooling area of multi-slotted cooling liner.

• Journal of the korean Society of Automotive Engineers
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• v.17 no.3
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• pp.11-18
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• 1995

본 논문에서는 주철 라이너를 삽입한 알루미늄 블럭 엔진 개발과정에서 주조 불량이 발생하였을때, 냉각계에 일어나는 제반 현상을 분석하고, 이를 해결해 나가는 과정을 기술하였다. 이를 위하여 주철 블럭과 알루미늄 블럭을 장착한 엔진의 피스톤 온도와 블럭의 열유속, 열정산을 측정하였다. 측정한 결과는 다음과 같다. 1. 알루미늄 블럭 제작시 주철 라이너와 알루미늄 블럭 사이에 공기층이 크거나, 용탕 충진이 불완전한 주조 불량이 발생하면 열접촉 저항이 커져 엔진 열전달 경로에 큰 영향을 준다. 2. 알루미늄 블럭 제작시 주조 불량이 발생하면 피스톤에서 라이너로의 전열량이 줄어듦에 따라 냉각수로의 전열량은 감소하는데, 6,000rpm, 전부하에서 알루미늄 블럭의 출력 대비 냉각수로의 방열량의 비는 38.3%이고, 주철 블럭은 44.1%이다. 3. 알루미늄 블럭 제작시 주조 불량이 발생하면, 피스톤 온도가 15-20.deg.C 정도 상승하여 피스톤 손상을 유발시킬 수 있다. 4. 알루미늄 블럭의 주조가 완벽하게 되어 주철 라이너와 알루미늄 몸체 사이에서의 열접촉저항이 없어지면, 스토로크 방향에 따른 금속면 온도 분포가 균일하게 된다. 5. 실린더 라이너의 주조상태 개선없이 오일젯을 사용한 결과 피스톤의 온도를 만족할 만한 수준으로 감소시켰다. 6. 6000rpm, 전부하에서 오일젯 적용시 출력 대비 냉각수로의 방열량의 비가 38.3%에서 36.2%로 감소하고, 출력대비 오일로의 방열량의 비는 9.6%에서 11.2%로 증가한다. 7. 오일젯 작용시 오일 펌프의 용량 증대와 오일 쿨러의 장착이 필수적이다.

• Journal of Power System Engineering
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• v.9 no.2
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• pp.5-13
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• 2005

새로운 엔진을 개발하기 위한 중요한 과정 중에 하나로서 엔진 연소실 가시화를 들 수 있다. 그러나 실제 운전상태에 있는 엔진 연소실을 가시화하기 위해서는 극복해야 할 여러 가지 어려운 점들이 있기 때문에, 지금까지는 간단한 실험적 접근방법 혹은 소수의 이론적 해석 방법만이 보고 된 상태이다. 본 연구에서는 가시화용 수정엔진을 개발하기 위해 필요한 몇 가지 중요한 사항들을 다루었다. 즉, 가시화용 수정엔진의 안전한 운전을 위하여 엔진 실린더 외부에 강제대류 효과를 주었고, 또한 실린더 두께 변화에 따른 온도 및 응력장의 분포를 정량적.정성적으로 고찰하였으며 다음과 같은 결론을 얻을 수 있었다. 첫째, 실린더 라이너 외벽을 강제대류로 냉각했을 경우, 열응력 감소에 매우 큰 효과를 보았다. 둘째, 가시화용 수정엔진 라이너의 최적 두께를 도출하였다. 셋째, 전통적인 주철 소재의 실린더 라이너와 비교 시, 주철 라이너는 연소에 의한 폭발 압력이 실린더 안전성에 큰 영향을 미치지 않는 것으로 보고 되었으나, 수정 라이너의 경우 연소압력 및 연소에 의한 연소열 모두 중요한 설계 인자임을 입증하였다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.10
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• pp.966-978
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• 2011

Transpiration cooling is the most effective cooling technique for the high-performance liquid rockets and air-breathing engines operating in aggressive environments with higher pressures and temperatures. When applying transpiration cooling, combustor liners and turbine blades/vanes are cooled by the coolant(air or fuel) passing through their porous walls and also the exit coolant acting as an insulating film. Practical implementation of the cooling technique has been hampered by the limitations of available porous materials. But advances in metal-joining techniques have led to the development of multi-laminate porous structures such as Lamilloy$^{(R)}$ fabricated from several diffusion-bonded, etched metal thin sheets. And also with the availability of lightweight, ceramic matrix composites(CMC), transpiration cooling now seems to be a promising technique for high-performance engine cooling. This paper reviews recent research activities of transpiration cooling and its applications to gas turbines, liquid rockets, and the engines for hypersonic vehicles.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.235-240
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• 2010

Transpiration cooling is the most effective cooling technique for liquid rocket and air-breathing engines operating in aggressive environments with higher pressures and temperatures. Combustor liners and turbine vanes are cooled by the coolant(air or fuel) passing through their porous walls and also the exit coolant acting as an insulating film. However, its practical implementation has been hampered by the limitations of available porous materials. The search for more practical methods of increasing the internal heat transfer within the walls has led to the development of multi-laminate porous structures, such as Lamilloy$^{(R)}$ and Transply$^{(R)}$. This paper reviews recent research activities of transpiration cooling for the propulsions of liquid rocket, gas turbine, and scramjet.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.445-448
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• 2008

The unsaturated polyester(UP) and epoxy resin have a superior material properties and a chemical resistance using sewerage pipes rehabilitation. However, UP and epoxy have not a low temperatures harding, the requirement $8{\sim}11$ hours long times harding and heating system used by reinforcement liner. This study is to evaluate the effects of low temperature harding properties methyl methacrylate(MMA) monomer using expanded polystyrene(EPS) and UP in addition of initiator and promoters. From the test result, viscosity tends to increase with increasing EPS and UP contents. However, harding time change of the MMA resins which it follows in addition of the initiator and promoter.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.929-932
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• 2008

The unsaturated polyester(UP) and epoxy resin have a superior material properties and a chemical resistance using sewerage pipes rehabilitation. However, UP and epoxy have not a low temperatures harding, the requirement $8{\sim}11$ hours long times harding and heating system used by reinforcement liner. This study is to evaluate the effects of low temperature harding properties methyl methacrylate(MMA) monomer using expanded polystyrene(EPS) in addition of initiator and promoters. From the test result, viscosity tends to increase with increasing EPS contents. However, harding time change of the MMA resins which it follows in addition of the initiator and promoter.

• Journal of Food Hygiene and Safety
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• v.25 no.4
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• pp.346-353
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• 2010

This study was conducted to determine cleaning effects of environmental-friendly washing detergent on milking installation in dairy farms. Milking machine, cooling machine and milking liner were washed by alkaline detergent and acid detergent for first three weeks and alkaline detergent and environmental~friendly detergent for next three weeks and the results get through microorganism and physico-chemistry analysis at the five district dairy farms different from environment. E-coli, coliform, fecal coliform, staphylococcus aureus, fecal streptococcus, prsudomonas aeruginosa and yersinia were not found in all of the dairy farms, and total colony counts were no difference compared with chemical detergent. The water for washing exceeded the determining acceptable level of nitrate nitrogen in the Anseong, Onyang and Cheonan and the remaining substance of washed water was also high levels. The cause of the result was that the level of nitrate nitrogen of water is basically high. Therefore, this study indicated that washing effect is no differences between environmental-friendly detergent and chemical detergent by washing for milking machine and cooling machine. Above all, producing high quality milk is to manage the water quality as well as using detergent.