Experimental and kinetic modelling study of n-butanal auto-ignition in a shock tube

Ignition delay time measurements for mixtures of pure n-butanal/n-pentanal(1%)–O2/Ar were carried out in a low pressure shock tube at equivalence ratios of 0.5, 1.0 and 2.0, at reflected shock pressures of 1 and 3 atm and at reflected shock temperatures of 1100-1850 K. Additional experiments were carried out in a single pulse shock tube to determine the speciation profiles of the fuel and intermediates species under pyrolysis conditions for mixtures of pure butanal/pentanal (3%) –Ar (97%) at reflected pressure of 1.9 atm and reflected temperatures of 1096—1368 K. Two kinetic mechanisms have been developed for both aldehydes following two different approaches: a detailed approach and a lumped approach. Both the mechanisms, developed to describe the high temperature oxidation and to explore the important reaction classes which control the auto-ignition behaviour of n-butanal, are found to be well in agreement with the experimental data.