Measurement of laminar burning velocity – A new PIV approach

This paper presents an experimental approach to measure the laminar burning velocities and Markstein lengths by using particle image velocimetry. The spherical outwardly propagating flame configuration of propane/air mixtures over a wide range of equivalence ratios were used to investigate the new PIV approach. The flame speed in the laboratory frame and the velocity of fresh gas at the entrance of the preheat zone were directly calculated from the PIV images with a sub-pixel accuracy. The laminar burning velocity as a function of flame stretch was directly deduced from the flame speed and fresh gas velocity without using any fuel properties. The unstretched laminar burning velocities were obtained through a linear extrapolation to zero stretch. The Markstein lengths were deduced from the linear relationship between the flame speed and flame stretch rate. The estimated values of laminar burning velocities and Markstein lengths were compared with experimental results of the literature