Abstract:The effects of atmospheric pressure, unburned mixture temperature and equivalence ratio on the secbutanolair laminar flow combustion were investigated by the smear method and the spherical flame diffusion method. The coupling effects of environmental parameters and equivalence ratio on the unstretched laminar burning propagation velocity and the change value, change rate and ratio of change rate of unstretched laminar burning propagation velocity were mainly analyzed. The results show that the larger the pressure is, the smaller the variation of unstretched laminar propagation velocity is under the coupling of ambient pressure and equivalent ratio. The ratio of change rate of unstretched laminar burning propagation velocity is increased with the increasing of equivalence ratio with downward trend for the equivalence ratio around 1.10. When the equivalence ratio is less than 1.05, the low pressure environment has greater influence on the laminar flow combustion. Under the coupling of ambient temperature and equivalence ratio, the propagation velocity of unstretched flame is more affected by higher ambient temperature when the equivalence ratio is in the range from 0.75 to 1.15. When the equivalence ratio is less than 0.85 or greater than 1.45, the equivalent ratio has great influence on the rate of nontensile laminar flow combustion.