In order to study the combustion characteristics and combustion stability of CH4/n-decane mixed fuel

the diffusion velocity of flame radius

the stretched flame speed

Marksein length

unstretched flame speed and laminar burning velocity of CH4/n-decane mixture were measured experimentally in a constant volume chamber at initial pressure of 0.1MPa

initial temperature of 420K

over the equivalence ratios range of 0.8－1.5 and over the methane concentration range of 0－0.8. The influences of methane concentration on Marksein length and laminar burning velocity were investigated. Results showed that at equivalence ratio of 1.3

the observed cellular structure at the end of flame propagation disappeared with the increase of methane concentration and the flame front became smooth

along with the increase of the flame stability; the decreasing trend of Marksein length with the growing equivalence ratio became slower due to the increase of methane concentration

and there was a critical equivalence ratio

with the methane concentration of 0.8 the combustion stability was poor when the equivalence ratio was smaller than 1.2 and to the contrary the combustion stability was better when the equivalence ratio was bigger than 1.2; over the equivalence ratio of 1.0－1.3 the laminar burning velocities of mixed fuel with methane concentration of 0.2 and 0.4 were faster

and over the equivalence ratios range of experiment conditions the laminar burning velocities of mixed fuel with methane concentration of 0.8 were slower.