Abstract
Experiments have been carried out with extremely lean, quiescent propane-mixtures to examine the influence of flame propagation direction under normal gravity and microgravity conditions on propagation limit and distance of flame propagation in a tube. The main conclusions are follows : (1) a flame behavior is affected by the direction and gravity conditions, (2) the minimum flame speed of lean propane-air mixtures under microgravity is about 10cm/s, (3) under microgravity the propagation limit sifts to lower value more than that obtained under normal gravity.
