Miniaturized passively Q-switched Nd:YAG/Cr(4+):YAG lasers are promising candidates as spark sources for sophisticated laser ignition. The influence of the complex spatial-temporal pulse profile of such lasers on the process of plasma breakdown and on the energy transfer is studied. The developed measurement technique is applied to an open ignition system as well as to prototypes of laser spark...

The tangent linear approximation (TLA) developed in Almohammadi et al. (Combust. Flame 230, 111426) is extended to estimate the sensitivity of ignition delay time with respect species enthalpies and entropies. proposed method relies on integrating linearized system equations governing evolution state vector’s partial derivatives variations thermodynamic parameters. estimated through a temperatu...

Numerical study of two dimensional supersonic hydrogen-air mixing layer is performed to investigate the effect of turbulence and chemical additive on ignition distance. Chemical reaction is treated using detail kinetics. Advection upstream splitting method is used to calculate the fluxes and one equation turbulence model is chosen here to simulate the considered problem. Hydrogen peroxide is us...

The spontaneous ignitability of Pinus halepensis pine needles was evaluated. Fire points and times taken for irradiated fuels to be ignited were correlated, at given heat intensity, to the airflow around the specimen and the sample size. The tests showed that increase of the airflow rate above 1.5 lmin 1 increased considerably the fire point values and ignition delay times. On the contrary, the...

Knowledge about ignition processes of coal in fluidized beds is of importance for the start-up and dynamic control of these combustors. Initial experiments in a transparent fluidized bed scale model showed the existence of a considerable induction period for the ignition of char, especially at low bed temperatures (e.g., 800-950K for bituminous coal). This paper focuses on char-ignition delay a...