Effects of initial temperature on the laminar combustion characteristics of CH4/RP-3 mixed fuel

The laminar combustion characteristics of CH4/RP-3 mixed fuel were studied in a constant volume chamber at initial pressures of 0.1MPa, equivalence ratios of 0.7-1.5, methane volume fraction of 0, 0.4, 0.8 and three initial temperatures. The flame propagation photos, laminar burning velocity and Markstein length were obtained, and the effects of initial temperature on laminar burning velocity and combustion stability of CH4/RP-3 mixed fuel were analyzed. The results showed that when the flame stretch was close to 0, the nonlinear fitting method NLM2 can well predict the change of stretched flame speed with varying stretch rate, and extrapolation can obtain more accurate unstretched flame speed. The initial temperature had a great influence on the flame propagation velocity of lean mixed fuels, but little effect for chemical equivalent ratio or concentrated mixtures. The laminar burning velocities of CH4/RP-3 mixed fuel with three methane volume fractions increased with the growing initial temperature. When the initial temperature was 420K, Markstein length reduced fastest with the increase of equivalence ratio, and when the initial temperature was 480K, Markstein length reduced slowest with the increase of equivalence ratio. Under lean and stoichiometric mixture conditions, with the increase of initial temperature, Markstein length decreased and combustion stability became worse. Under rich mixture condition, Markstein length with different initial temperatures tended to the same, and the effects of initial temperature on combustion stability was small.