등방 난류 유동장내 난류 예혼합 화염 전파의 통계적 시뮬레이션

Abstract

등방 난류 유동장내를 전파하는 난류 예혼합 화염에 관한 이론적인 연구를 수행하였다. 통계적 시간 급수 방법을 사용하여 화염 표면을 따라 미연 가스 영역의 난류 유동장을 모사 (simulate) 하고 2차원 화염면 운동 알고리즘을 사용하여 화염 전파에 따르는 화염면의 성질을 수치적으로 모사하였다. 본 연구의 목적은 난류 예혼합 화염의 기하학적 구조와 전파 속도를 효율적으로 예측할 수 있는 계산법을 개발하고 검증 하는데 있다. 계산 결과는 다양한 난류 강도와 레이놀즈수를 갖는 수소-공기 혼합 가스에 대하여 측정된 기존의 실험 결과와 비교하였다. 본 연구에서 제안된 2차원 계산은 화염 반경 성장율, 화염 반경 변형율, 프랙탈 차수등에서 측정치와 유사한 경향을 보였으며, 이 방법이 보다 복잡한 형태의 난류 화염 전파에 효율적으로 적용될 수 있음을 확인하였다.

A theretical investigation of turbulent premixed flames propagating in isotropic turbulence is presented. Flame surface properties were numerically simulated using a two-dimensional flame propagation algorithm combined with statistical time series simulation of unburned gas velocities along the flame surface. The objective is to develop and test an efficient technique to predict the propagation speed of flame as well as the geometric structure of the flame surfaces. Predictions were compared with existing experimental data for flames propagating in a closed vessel charged with hydrogen/air mixture with various turbulence intensities and Reynolds numbers. Two dimensional time dependent simulation resulted in correct trends of the measured flame data. Comparisons were made in flame radius growth rate, rms flame radius fluctuations, and average perimeter and fractal dimensions of the flame boundaries. The reasonable behavior and high efficiency proves the usefulness of this method in complex problems of flame propagation.

A theretical investigation of turbulent premixed flames propagating in isotropic turbulence is presented. Flame surface properties were numerically simulated using a two-dimensional flame propagation algorithm combined with statistical time series simulation of unburned gas velocities along the flame surface. The objective is to develop and test an efficient technique to predict the propagation speed of flame as well as the geometric structure of the flame surfaces. Predictions were compared with existing experimental data for flames propagating in a closed vessel charged with hydrogen/air mixture with various turbulence intensities and Reynolds numbers. Two dimensional time dependent simulation resulted in correct trends of the measured flame data. Comparisons were made in flame radius growth rate, rms flame radius fluctuations, and average perimeter and fractal dimensions of the flame boundaries. The reasonable behavior and high efficiency proves the usefulness of this method in complex problems of flame propagation.