An experimental study on the instability of RP-3 aviation kerosene/air premixed flame.

• This paper focused on the instability of RP-3 aviation kerosene/air premixed flame. • Experiments were carried out in a constant volume chamber to study the unstable flame propagation processes of RP-3/air premixed flame over wide initial conditions. • The transition acceleration onset was measured and the effects of diffusional-thermal, hydrodynamic instability and stretch rate in spherically expanding flames on R cr were analyzed. • The acceleration exponent α was obtaind and with the increase of equivalence ratio, the changes in α and its corresponding flame radius were analyzed. In the present work, experiments were carried out in a constant volume chamber to study the unstable flame propagation processes of RP-3/air premixed flame at initial pressures of 0.1, 0.2 and 0.3 MPa, initial temperatures of 420, 450 and 480 K and over a wide equivalence ratio range from 1.0 to 1.7. Results show that the RP-3/air premixed flame tends to be unstable with increased equivalence ratio and initial pressure. The measured transition acceleration onset and calculated critical flame radius R cr agree well with each other. The effects of diffusional- thermal, hydrodynamic instability and stretch rate in spherically expanding flames on α show that α of RP-3/air premixed flame strongly depends on effective Lewis number L e eff and Markstein number Ma. With the increase of equivalence ratio, acceleration exponent α tends to increase and the flame radius corresponding to the onset of similarity acceleration decreases. [ABSTRACT FROM AUTHOR]