디젤분무의 액적분열 모델에서 초기 액적형상 및 항력의 영향
- Alternative Title
- The Effects of Initial Droplet Shape and Drag Force on Modeling of Diesel Sprays
- Abstract
- 디젤분무의 거동을 해석하기 위한 미립화 및 액적분열 모델에 대한 연구가 활발히 이루 어지고 있다. 공기역학적 항력에 의한 액적의 변형을 고려한 미립화 모델인 TAB 모델을 개선한 ETAB, DDB, APTAB 모델을 최근에 개발된 커먼레일 고압 연료분사장치에 의한 연료분무에 적용하여 각 모델의 예측성능을 비교하였다. 또한 초기에 분출하는 액적이 구 형이 아닌 편원체로 가정하고, 주위액적에 의한 공기역학적 항력의 변화를 고려한 새로운 모델을 제시 한다.
KIVA 코드를 사용한 수치계산에서 ETAB, DDB, APTAB 모델 모두 분무선단도달거리 는 실험결과와 잘 일치하였으나 분무내 액적의 평균직경은 실험보다 다소 크게 예측한다. 초기 액적 형상을 구형이 아닌 편원체로 가정한 경우에는 구형인 경우와 거의 차이가 없는 결과를 보인다. 반면에 주위액적의 영향을 고려하기 위하여 액적의 공기역학적 항력계수를 액적분열기간 중에 분출 후 경과시간에 비례하여 증가시키면, 분무내 액적의 평균직경이 작아져 실험에 근접한 결과를 얻을 수 있었다.
A number of droplet breakup models have been developed to predict the diesel spray. The capabilities of droplet deformation and breakup models such as ETAB, DDB and APTAB models are evaluated in modeling the high pressure diesel sprays of a common rail injection system. A new model that takes into account the non-spherical shape of droplets and the reduced drag force by the presence of neighbouring droplets.
The KIVA calcuriations with ETAB, DDB, and APTAB models predict well the spray tip penetrations of the experiment, but overestimate the tauter Mean Diameter(SMD) of droplets. The calculation with non-spherical droplets injected from the nozzle shows very similar results with the calculation with spherical droplets. The drag coefficient which is linearly increased with the time after start of injection during the breakup time gives the smaller SMD that agrees well with the result of the experiment.
A number of droplet breakup models have been developed to predict the diesel spray. The capabilities of droplet deformation and breakup models such as ETAB, DDB and APTAB models are evaluated in modeling the high pressure diesel sprays of a common rail injection system. A new model that takes into account the non-spherical shape of droplets and the reduced drag force by the presence of neighbouring droplets.
The KIVA calcuriations with ETAB, DDB, and APTAB models predict well the spray tip penetrations of the experiment, but overestimate the tauter Mean Diameter(SMD) of droplets. The calculation with non-spherical droplets injected from the nozzle shows very similar results with the calculation with spherical droplets. The drag coefficient which is linearly increased with the time after start of injection during the breakup time gives the smaller SMD that agrees well with the result of the experiment.
- Author(s)
- 원영호
- Issued Date
- 2001
- Type
- Research Laboratory
- URI
- https://oak.ulsan.ac.kr/handle/2021.oak/3771
http://ulsan.dcollection.net/jsp/common/DcLoOrgPer.jsp?sItemId=000002024098
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