• Title/Summary/Keyword: Premixed Combution

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An experimental study on turbulence characteristics of mixture and combustion characteristics of doubled jet burner flames (미연혼합기의 난류특성과 이중분류버너화염의 연소특성에 관한 실험적 연구)

  • Choe, Gyeong-Min;Jang, In-Gap;Choe, Byeong-Ryun
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.21 no.2
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    • pp.213-223
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    • 1997
  • Premixed flame is better than diffusion flame to accomplish a high loading combustion. Since the turbulent characteristics of unburned mixture has a great influence on the flame structure, it is general that many researchers realize a high loading combustion with strengthening turbulent intensity of unburned mixture. Because turbulent premixed flame reacts efficiently on the condition of distributed reaction region, we made high turbulent premixed flame in the doubled impingement field. We investigated turbulent characteristics of unburned mixture with increasing shear force and visualized flames with direct and Schlieren photographs. And the combustion characteristics of flame was elucidated by instantaneous temperature measurement with a thermocouple, by ion currents with a micro electrostatic probe, by radical luminescence intensity and local equivalence ratio. Extremely strong turbulent of small scale is generated by impingement of mixture, and turbulent intensity of unburned mixture increased with the mean velocity. As a result of direct photographs, visible region of flame became longer due to increasing central direction flux. But as strengthed turbulent intensity, visible region of flame turned to shorter and reaction occurred efficiently. As strengthened turbulent intensity of mixture with increasing flux of central direction, maximum fluctuating temperature region moved to radial direction and fluctuation of temperature became lower. The reason is influx of central direction which caused flame zone to move toward radial direction, to maintain flame zone stable and to make flame scale smaller.

Effects of Injection Strategies on the Partial Premixed Charge Combustion and Emission Characteristics in a Diesel Engine (디젤엔진의 부분 예혼합 연소 및 배기 특성에 대한 분사전략의 영향)

  • Kim, Jaewoong;Kim, Yungjin;Park, Sangki;Lee, Kihyung
    • Transactions of the Korean Society of Automotive Engineers
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    • v.21 no.4
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    • pp.83-88
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    • 2013
  • Recently, PCCI (premixed charge compression ignition) combustion is studied to reduce both NOx and PM because of homogeneous mixture formation and lower combustion temperature. It has also merit of increasing thermal efficiency owing to better air-fuel mixure. However, it is well known that PCCI combustion has a weakness in fuel economy because PCCI combustion tends to start before TDC. Therefore, it is necessary to find an optimal conditions for PCCI combustion which maintains reduction of NOx, PM and increase of thermal efficiency. In this study, pPCCI combustion was realized by adding early injection strategy to a conventional diesel engine. In addition, the characteristics of pPCCI combustion was analized by comparing conventional diesel injection strategy. The results show that NOx and PM per power in pPCCI combution were reduced compared to a conventional diesel combustion.