난류 예혼합 제트 화염 전파의 수치 계산

Abstract

난류 예혼합 제트 화염의 전파에 관한 수치적 연구를 수행하였다. 화염은 얇은 화염편 영역으로 국한하였으며 계산을 용이하게 하기 위하여 기존의 난류 경계층 모델링을 사용하였다. ?鳧윳? 변수가 연료 당량비에 무관한 기존 모델의 단점을 극복하기 위하여 생성항에 층류 화염 전파 속도를 포함시켰다. 생성항에 사용된 변수들은 당량비 3.57, 레이놀즈수 40000의 실험 데이터와 합치하도록 선택되어졌다. 모델의 검증을 위하여 기존의 실험 데이터가 알려져 있는 난류 예혼합 제트 화염에 적용하여 그 결과를 비교하였다. 본 연구에서 제안된 모델은 반응도, 난류 화염 전파 속도, 축방향 속도, 축방향 난류 속도 성분 등에서 당량비의 영향을 잘 묘사하고 있으며, 실험치와 같은 경향을 보였으나, 일반적으로 실험치를 다소 과소 평가하였다.

A numerical analysis of turbulent premixed jet flames is described, limited to the thin laminar-flamelet regime. To make the computation practical, existing turbulent boundary layer model was used with a modified source term for reaction progress variable. The Source term involves laminar burning velocity in order to account the effects of fuel equivalence ratios. The source term includes additional parameters, which were obtained by matching with the measurements at φ=3.57, Re=40000. Test results of the model were compared with existing measurements of turbulent premixed jet flames. The prosed model describes accurately the effects of fuel equivalence ratios on reaction progress variables, turbulent burning velocities, mean axial velocities on burner axis and axial velocity fluctuations. However the model slightly underestimated the measurements.

A numerical analysis of turbulent premixed jet flames is described, limited to the thin laminar-flamelet regime. To make the computation practical, existing turbulent boundary layer model was used with a modified source term for reaction progress variable. The Source term involves laminar burning velocity in order to account the effects of fuel equivalence ratios. The source term includes additional parameters, which were obtained by matching with the measurements at φ=3.57, Re=40000. Test results of the model were compared with existing measurements of turbulent premixed jet flames. The prosed model describes accurately the effects of fuel equivalence ratios on reaction progress variables, turbulent burning velocities, mean axial velocities on burner axis and axial velocity fluctuations. However the model slightly underestimated the measurements.