Flame Propagation Along Matchstick Arrays

Experimental observations are presented on flame propagation along uniform, linear, horizontal arrays of vertically oriented matchsticks. Matchstick height and spacing between matchsticks are varied. Reported results include necessary conditions for flame propagation, linear rates of flame propagation, and char angle—the angle between the horizontal and a photographically recorded line of incipient char formation on the face of the matchstick array. Theoretical explanations for the experimental observations are offered on the basis of a model which employs an ignition temperature and uses previously determined flame shapes for individually burning cellulosic cylinders. The remarkably good agreement between theory and experiment supports the contention that convective effects are of primary importance in flame propagation at matchstick size scales.