한국자동차공학회논문집 (Transactions of the Korean Society of Automotive Engineers)

  • 제25권2호
  • /
  • Pages.179-189
  • /
  • 2017
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  • 1225-6382(pISSN)
  • /
  • 2234-0149(eISSN)
한국자동차공학회 (The Korean Society of Automotive Engineers)
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정상유동 장치에서 유동 특성 평가 방법에 대한 연구(5) - 평가위치의 영향

Study on Evaluation Method of Flow Characteristics in Steady Flow Bench(5)-Effect of Evaluation Position

  • 조시형 (서울과학기술대학교 에너지환경전문대학원) ;
  • 엄인용 (서울과학기술대학교 기계자동차공학과)
  • Cho, Siehyung (Graduate School of Energy & Environment, Seoul National University of Science and Technology) ;
  • Ohm, Inyong (Department of Mechanical & Automotive Engineering, Seoul National University of Science and Technology)
  • 투고 : 2017.01.13
  • 심사 : 2017.01.20
  • 발행 : 2017.03.01
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초록

This paper is the fifth investigation on the methods of evaluating flow characteristics in a steady flow bench. In previous studies, several assumptions used in the steady flow bench were examined and it was concluded that the assumption of the solid rotation may lead to serious problems. In addition, though the velocity profiles were improved as the measuring position went downstream, the distributions were far from ideal regardless of the valve angle and evaluation position. The eccentricities were also not sufficiently small to disregard the effect on impulse swirl meter (ISM) measurement. Therefore, the effect of these distribution and eccentricity changes according to the positions needs to be analyzed to discuss the method of flow characteristics estimation. In this context, the effects of evaluation position on the steady flow characteristics were studied. For this purpose, the swirl coefficient and swirl ratio were assessed and compared via measurement of the conventional ISM and calculation based on the velocity by particle image velocimetry(PIV) from 1.75B, 1.75 times bore position apart from the cylinder head, to the 6.00B position. The results show that the swirl coefficients by ISM strictly decrease and the curves as a function of the valve lift become smooth and linear as the measuring position goes downstream. However, the values through the calculation based on the PIV are higher at the farther position due to the approach of the tangential velocity profile to ideal. In addition, there exists an offset effect between the velocity distribution and eccentricity in the low valve lift range when the coefficients are estimated based on the swirl center. Finally, the curve of the swirl ratio by ISM and by PIV evaluation as a function the measuring position intersect around 5.00B plane except at $26^{\circ}$ valve angle.

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과제정보

연구 과제 주관 기관 : 서울과학기술대학교

참고문헌

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