• Title/Summary/Keyword: 연소율

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Experimental study of extinguishment of the pure diffusion flame using water spray (수분무를 이용한 순수확산화염의 소화에 관한 실험적 연구)

  • Jang, Yong-Jae;Kim, Myeong-Bae;Kim, Jin-Guk
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.20 no.2
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    • pp.624-631
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    • 1996
  • This study describes extinguishment mechanism of the purely buoyant diffusion flame using the water spray. Experiments are systematically carried out for the oul pool fire with the six different atomizing nozzles. From the measurement of burning rate which represents the combustion intensity of fire, it is observed that the water spray is able to act to enhance fire rather than to extinguish fire. The air entertainment due to the water spray is visualized to understand this phenomenon, acting to enhance fire. In order to observe effects of droplet size on fire extinguishment, and amount of water which reaches the flame base, fuel surface, and mean diameter of droplets are measured. When water droplets are too small, they do not reach the flame base because they can the water spray having too small doplets is ineffective for extinguishment of the oil fire.

A Study on the Transient Combustion Characteristic in PE-GOX Hybrid Rocket (PE-GOX 하이브리드 로켓에서의 과도 연소 특성 연구)

  • Cho, Sung-Bong;Lee, Jung-Pyo;Song, Na-Young;Kim, Soo-Jong;Kim, Jin-Kon
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2006.11a
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    • pp.228-231
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    • 2006
  • In general, burning time is not considered with a factor of an empirical relation on the combustion characteristic in hybrid propulsion system. So, The effect of burning time on hybrid combustion characteristics and propulsion characteristics was studied. As results, regression rate is decrease with burning time, but fuel mass flux is maintained nearly constant with burning time at given oxidizer mass flux.

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Fire Characteristics of Flaming and Smoldering Combustion of Wood Combustibles Considering Thickness (목재 가연물의 두께에 따른 화염연소와 훈소상태에서의 화재특성)

  • Kim, Sung-Chan;Nam, Dong-Gun
    • Fire Science and Engineering
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    • v.29 no.4
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    • pp.67-72
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    • 2015
  • A series of fire tests was conducted to examine the fire characteristics of flaming and smoldering combustion of engineered wood products, which have been widely used for furniture and finishing materials in buildings. The engineered wood products of MDF, plywood, and chipboard were ignited by a radiant cone heater with incident heat flux of $50kW/m^2$. During the fire test, key parameters representing the fire characteristics such as the heat release rate, yield rate of combustion product, and effective heat of combustion were quantified in terms of thickness. The tests show two peak points of HRRPUA due to lateral fire propagation in the initial stage, followed by later fire penetration through the specimen thickness. The mass loss rate of flaming combustion was 5 times higher than that of smoldering combustion, while the CO yield rate of smoldering combustion was 10 times higher than that of flaming combustion. This study can contribute to the understanding of fire behavior of wood combustibles and provide useful data for fire analysis.

A study on the thermodynamic analysis of combustion characteristics of diesel engine (디이젤機關 燃燒特性의 熱力學的 解析에 관한 硏究)

  • 이창식
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.10 no.2
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    • pp.215-222
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    • 1986
  • This paper presents the results of investigation, the aim of which was to predict theoretically the processes of thermodynamic cycle of M-combustion chamber type diesel engine. The combustion characteristics in cylinder are evaluated from the energy equation for an thermodynamic system in engine cylinder. In order to predict the combustion pressure in cylinder, the engine is divided in various control volumes. The simulation results of combustion characteristics show that the comparison of computed and measured values brings about the good coincidence.

Flmae Visualization of the sector combustor (분할연소기의 화염 가시화 연구)

  • Kim, Bo-Ra-Mi;Choi, Chea-Hong;Kim, Chun-Taek;Choi, Seong-Man
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2009.11a
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    • pp.213-216
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    • 2009
  • In order to see the flame behavior in the gas turbine combustor, combustion test was performed by using sector combustor. Ignition test with torch ignition system was carried out at the various combustor inlet velocity and air fuel ratio. Also, flame blow out limit was measured by changing fuel flow rate with fixed air mass flow rate. In the test results, stable ignition is possible at air excess ratio of 6 and this limit is gradually increased with combustor inlet air velocity. The minimum blow out limit is about 4 at 40 m/s of combustor inlet velocity. This blow out limit is also increased up to about 10 with increasing combustor inlet velocity.

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A Study on Combustion Characteristic with Chamber Pressure in Hybrid Rocket (하이브리드 로켓에서의 압력에 따른 연소특성에 관한 연구)

  • Cho, Jung-Tae;Kim, Gi-Hun;Lee, Jung-Pyo;Kim, Hak-Chul;Park, Seon-Woo;Park, Joon-Hyng;Han, Hee-Soo;Hwang, Jae-Woong;Moon, Hee-Jang;Sung, Hong-Gye;Kim, Jin-Kon
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2008.11a
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    • pp.243-246
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    • 2008
  • The combustion characteristic of solid fuel with chamber pressure were experimentally studied in hybrid combustion. This paper was experimental confirmed whether solid fuel affected not only oxidizer mass flux but also chamber pressure. Poly-Ethylene(PE) was used as fuel, GOX was used as oxidizer. Chamber pressure was controled by nozzle throat diameter 6mm and 9mm. In low oxidizer mass flux, solid fuel regression rate was affected not only oxidizer mass flux but also chamber pressure. As well, the regression rate increase as chamber pressure increase with same oxidizer mass flux.

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Analysis of Forest Fuel Quality by Forest Fire Damage (산림연료 특성별 산불피해도 분석)

  • Kwon, Chun-Geun;Lee, Si-Young;Lee, Myung-Woog;Lee, Hae-Pyeong
    • 한국방재학회:학술대회논문집
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    • 2011.02a
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    • pp.196-196
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    • 2011
  • 산림연료 특성별 산불피해도 분석을 위하여 산불피해의 조사지역은 2009년, 2010년 산불이 발생했던 강원도 고성지역과 양양지역, 강릉지역과 삼척지역을 조사 대상지역으로 선정하였으며, 고성군의 경우 숲구조가 유령림인 활엽수림이 2개소, 칩엽수림 1개소, 장령림인 활엽수림 2개소로 총 5개소, 양양군은 숲구조가 유령림인 침엽수림이 1개소, 장령림 침엽수림 2개소 총 3개소, 삼척시의 경우는 숲구조가 유령림인 침엽수림이 1개소 외 대조구 장령림 침엽수림 1개소, 강릉시의 경우 숲구조가 장령림인 침엽수림이 3개소 총 13개소를 각각 대상지로 선정하였다. 산림연료 특성별 산불피해도를 조사하기 위한 조사지 규모는 $10m{\times}10m$로 하였으며, 현장 조사 항목은 조사지내의 산불피해 상태, 조사지 지형특성으로 나누어 조사를 실시하였다. 산불피해 상태는 산불진행방향, DBH, 총수고, 지하고, 고사여부, 편면연소, 밀도, 수간피해율, 수관피해율 등을 조사하였고, 조사지의 지형특성을 알아보기 위해 조사지의 위치(GPS), 해발고도, 사면방위, 산지경사, 지형을 조사하였다. 현장조사를 위한 조사장비로는 조사지의 지형도, 야장, 디지털 카메라, GPS, 수고측정기, 직경테이프, 캘리퍼, 50m 줄자 2개, 2m 폴대, 클리노메타, 바인더끈 등을 사용하였다. 산불사례 현장조사를 통해 임목고사여부, 편면연소, 수간피해율, 수관피해율 등의 산불피해 특성을 분석한 결과 연료의 특성별 유령림과 장령림의 편면연소율은 유령림은 97.3%, 장령림은 16.5%로 유령림의 편면연소율이 장령림보다 80.8% 더 피해를 받는 것으로 나타났으며, 수관피해율은 유령림은 95.4%, 장령림은 19.9%로 유령림의 수관피해율이 장령림보다 75.5%더 피해를 입은 것으로 조사 되었다. 또한 임목고사율은 유령림은 73.8%, 장령림은 24.5%로 유령림의 임목고사율이 장령림보다 49.3% 더 피해를 받는 것으로 분석 되었다.

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Characteristics of canola biodiesel fuel blended with diesel on the combustion and exhaust gas emissions in a compression ignition diesel engine (압축착화 디젤기관의 연소 및 배기가스에 대한 카롤라 바이오디젤 혼합 연료의 특성)

  • Yoon, Sam Ki;Kim, Min Soo;Choi, Nag Jung
    • Journal of Advanced Marine Engineering and Technology
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    • v.38 no.9
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    • pp.1081-1086
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    • 2014
  • An experimental study was performed in order to compare with the case of using pure diesel the characteristics of combustion pressure and exhaust emissions when the engine speed was changed in a CRDI 4-cylinder diesel engine using biodiesel( Canola oil) blended and pure diesel fuel. As a results, the combustion pressure was decreased with increasing biodiesel blended rate when engine speed was 1,000, 1,500, 2000(rpm). but the combustion pressure of the engine speed 2,500rpm was increased with increasing biodiesel blended rate. The emission results show, that CO was decreased with increasing biodiesel blended rate and engine speed. The emission of $CO_2$, NOx, were increased with increasing biodiesel blended rate and engine speed.

Study of Combustion Characteristics with Compression Ratio Change in Ultra-Lean LPG Direct Injection Engine (압축비 변화에 따른 초희박 직접분사식 LPG엔진의 연소특성 연구)

  • Cho, See Hyeon;Yoon, Jun Kyu;Park, Cheol Woong;Oh, Seung Mook
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.38 no.10
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    • pp.837-844
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    • 2014
  • Automotive manufacturers have recently developed various technologies for improving fuel economy and satisfying enhanced emission regulations. The ultra-lean direct injection engine is a promising technology because it has the advantage of improving thermal efficiency through the deliberate control of ignition. A conventional LPG engine has been redesigned to an ultra-lean-burn LPG direct injection engine in order to adopt combustion system of ultra-lean-burn. This study is aimed at investigating the effect of a change in the compression ratio on the performance and emission characteristics of a lean-burn LPG engine. The fuel consumption, heat release rate, combustion pressure, and emission characteristics are estimated depending on changing the effect of compression ratio. When the compression ratio is increased, it is difficult to improve the fuel consumption owing to an unstable combustion state, but the total hydrocarbon and nitrogen oxide emissions are reduced.