• Journal of Advanced Marine Engineering and Technology
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• 제27권5호
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• pp.624-632
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• 2003

In the gasoline engine industry. there has been a trend towards the development of high performance engines with improved fuel efficiency, reduced weight and smaller sizes. These trends help to solved engine problems related to thermal load and abnormal combustion. In order to investigate these Problems, a thin film-type probe for instantaneously measuring temperatures has been suggested. A method for manufacturing such a probe was established in this study. The instantaneous surface temperature of a constant volume combustion chamber was measured by this probe and the heat flux was obtained through Fourier analysis. A peak instantaneous temperature was obtained after 55∼60 ms from ignition and the temperature increased according to an equivalence ratio and varied differently according to the position of the probe. Total heat loss during combustion period was affected by the equivalence ratio and differed widely in accordance to the position of the probe.

• 한국자동차공학회논문집
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• 제9권4호
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• pp.103-111
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• 2001

In the present study, the internal combustion engine tends to high performance, fuel economy, small-sized. Therefore, it is necessary to solve the problems on thermal load, abnormal combustion, etc in the engine. Thin film instantaneous temperature probe was made, and the measuring system was established. The instantaneous surface temperatures in the constant volume combustion chamber were measured with this system and the heat flux was obtained by Fourier analysis. Maximum instantaneous temperatures were obtained after 55∼60ms from ignition and they increased as equivalence ratio and varied differently as the position of probe. Total heat loss during combustion time was affected by the equivalence ratio and differed widely as the position of probe.

• 한국전산유체공학회지
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• 제14권2호
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• pp.77-83
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• 2009

Operating medium or large scale industrial boilers in partial load condition, the burner should undergo the off-design points resulting in poor exhaust gas characteristics. To obtain the stable turn down performance, two or more burners can be used for the industrial boiler. In case multiple burners are adopted, the heat transfer can be enhanced by arranging the burners properly. In the present study, numerical simulations have been conducted for the combustion chamber of a 2 t/h class industrial boiler in order to clarify the heat transfer characteristics at the combustion chamber.

• 대한기계학회논문집
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• 제16권8호
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• pp.1595-1602
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• 1992

An energy efficient drying system, utilizing a heat pump to recover the wasted heat with high efficiency is proposed. In conventional drying systems, over-heating occurs through a condenser as the same amount of air is provided into the evaportator and the condenser. In order to prevent the over-heating, part of the outlet air from the drying chamber must be bypassed to increase the rate of vaporization in the drying chamber without release of the heat from the system. Since a part of the heat in the condenser is used to heat the air during the drying process of the proposed system, a high drying efficiency and low SPC(Specific Power Consumption) could be obtained, Comparing the performances between the proposed heat pump and a conventional one, it was found that the drying efficiency of the proposed heat pump is higher than that of the conventional heat pump by an amount of 7-25%.

• 한국자동차공학회논문집
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• 제5권5호
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• pp.178-187
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• 1997

For the experimental measurement of heat flux of DI diesel engine combustion chamber, the instantaneous temperature probes and data acquisition system were developed. By the analysis of measured temperatures at the cylinder head, the temperature at the point 3 which is located between intake and exhaust valve was higher than that of the other points. Temperatures at the point located mear the exhaust valve were higher than those of intake valve. The instantaneous and mean temperature at the cylinder head increases proportionally to the increase of the engine speed, while the temperature swing varies inversely. Temperature swings have influence on the maximum heat flux values from gas into head surface. It has been verified that these probes and data acquisition system perform well by the comparison of the trend of instantaneous temperature variation with that of measured combustion chamber pressure variation with respect to crank angle. It is presumed that these probes could be used in the measurement of other parts of combustion chamber as piston, cylinder wall etc. for the future study.

• 한국항공우주학회지
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• 제37권12호
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• pp.1201-1208
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• 2009

액체로켓 연소기의 재생냉각 챔버의 제작에 사용되는 구리합금의 성형성을 돔 장출 시험과 인장시험을 수행하여 평가하였다. 성형성 평가에 사용된 시편은 열처리 유무와 재료의 방향성을 고려하여 제작하여 고온 열처리와 재료의 방향성이 성형성에 미치는 영향을 평가하였다. 시험 결과 열처리 후 구리합금 재료의 성형한계 값은 열처리 전 시편의 성형한계 값에 비하여 증가하였으나, 시편의 제작 방향에 따른 성형성의 차이는 열처리 영향에 비하여 작게 나타났다. 그리고 성형성 평가 시험방법에 따라 성형한계 값이 다르게 나타났다. 이러한 결과 들로부터 연소기 재생냉각 챔버의 내측구조물에서 실린더 형상의 구조물을 벌징 공정으로 네킹이나 파손 없이 노즐 형상으로 성공적으로 성형하기 위해서는 벌징 전 재료에 대한 고온열처리가 매우 중요함을 확인하였다. 또한 시험방법이 성형성 평가에 크게 영향을 미치는 것을 확인하였다. 본 연구를 통하여 얻은 구리합금의 성형한계도는 이 재료를 사용하여 제작하는 연소기 재생냉각 챔버 노즐의 구조설계를 위한 데이터로 활용할 예정이다.

• 한국항공우주학회지
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• 제33권3호
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• pp.107-113
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• 2005

고성능 로켓엔진 연소기의 벽면 열유속 측정을 위하여 추력 2톤급 칼로리미터를 개발하였으며 고온에서 전열특성과 강도특성이 뛰어난 크롬동합금을 연소실 내벽 소재로 적용하였다. 전체적인 냉각성능은 경험식을 기반으로 하는 1차원 해석으로 확인하였으며 국부적인 냉각성능은 3차원 CFD 해석으로 검증하였다. 연소압 53 bar 조건에서 노즐목에서의 열유속은 43 $MW/m^{2}$ 으로 예측되었다. 연소실의 구조적인 안전성은 150 bar에서 2차원 해석과 시편에 대한 변형실험으로 확인하였다. 최종적으로 상온 150 bar에 대한 가압실험으로 안전성을 검증하였고 개발된 칼로리미터와 동일한 냉각성능을 갖는 시험용 노즐을 사용하여 예비시험을 수행하였다. 노즐목에서 측정된 열유속이 설계값에 비하여 10% 높았음에도 연소실 내벽에 열손상은 발생하지 않았다.

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 1998년도 가을 학술발표회논문집
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• pp.83-86
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• 1998

PVC사의 연신은 Fig. 1과 같이 끊는 물 속에서 이루어지며 연신 후 정전기 방지를 위해 유제를 습식 방법으로 처리한다. 따라서 건조와 heat set chamber에 들어가기 전 어느 정도의 수분과 유제를 함유한 체 각각의 chamber를 통과하며 건조, heat set된다. 본 연구의 목표는 연신 후 squeezing roller의 접압에 따른 건조시간의 관계와 heat set온도, 시간에 따른 열 수축률의 관계를 알아보고자 한다. (중략)

• 한국산업융합학회 논문집
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• 제6권2호
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• pp.103-108
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• 2003

This study was performed to find out drying characteristics and develop waste heat recovery dryer. this system was initiated in order to recover discharged waste heat of drying air from drying chamber in agricultural products dryer and recycle for additional heat source that could save drying cost. The system consists of drying chamber, fan, burner, circulation pump and heat exchanger made of fins and tubes. For the system performance, drying experiments with fresh pepper were conducted, and comparisons on fuel consumption amount and drying performance were made between conventional dryer and the heat recovery system attached dryer.

• 대한기계학회논문집B
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• 제21권11호
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• pp.1466-1474
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• 1997

In order to design and develop a spark ignition engine, many studies must be preceded about the characteristics of thermal flow. For measurement of transient wall temperature thin film thermocouples of Bendersky type were manufactured and these probes were fixed into the wall of combustion chamber. Surface wall temperatures were measured in experiments of various engine speeds. Transient heat fluxes were calculated from the wall temperature measurements. Pressure was measured from combustion chamber using pressure transducer and gas temperatures were calculated using the state equation of ideal gas. And instantaneous heat transfer coefficients were obtained. It will be the basic data for the formulae of instantaneous heat transfer coefficients.