A Study of Combustion Characteristics of lean Propane-air Mixtures

Abstract

Experiments have been carried out to examine the lean limits of propane-air mixtures in a combustion tube under microgravity. The microgravity technique achieved in a freely falling chamber is employed because the realization of symmetrical flame propagation in a combustion tube is possible. Experimental condition for the initial mixtures corresponds to room temperature and 0.1 MPa and the fuel used is propane of 99.9% purity. The experimental results show that (1) the flame propagation behavior of propane-air mixtures in a combustion tube close to lower propagation limit is irregular during the burning process, (2) under microgravity its propagation limit shifts to lower value more than that obtained under normal gravity, (3) the minimum flame speed of lean propane-air mixtures under microgravity is about 10cm/s.