A meso-scale channel was earlier developed [1] for the propagation of laminar lean premixed flames. This paper, therefore, reports the experimental variations of flame speed with inner meso-scale tube diameters (di), equivalence ratio (φ), and mixture flow rate (Q) with methane and propane fuels using the meso-scale channel developed earlier. Based on the flame front history, flame speed (SL) and propagation speed (Ud) were computed at temperature (T) greater than or equal to 300 K. As the theoretical predictions of flame speed suggested SLt = f(φ, T), the experimental values showed instead that SLe = f(Q, T). However, flame propagation speed was found to be dependent on all the three parameters – Ud = f(φ, Q, T). It was then deduced that mixture flow rate (Q) is the dominant factor in predicting SL especially in the range of equivalence ratios of 0.66–0.9. Scaling down the tube diameters was observed to have increasing effect on SL for both fuels but propane was shown to have more flame-front interaction due to its high Lewis number. Conventional flammability limits were extended.Keywords: Flame propagation, meso-scale, laminar
