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

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 tempera-tures 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 Rcr agree well with each other. The effects of diffusional-thermal, hydrodynamic instability and stretch rate in spherically expanding flames on alpha show that alpha of RP-3/air premixed flame strongly depends on effective Lewis number Leeff and Markstein number Ma. With the increase of equivalence ratio, acceleration exponent alpha tends to increase and the flame radius corresponding to the onset of similarity acceleration decreases.