Combustion kinetics ...................................................................................................................................... 1 Physical mixing and its effects on ignition, propagation and extinction ...................................................... 2 Mixing ...........................................................................................................

The present work addresses unsteady flame dynamics in a lean-premixed swirl-stabilized combustor, with attention focused on the transition of flame structure from a stable to an unstable state. It was found that the inlet temperature and equivalence ratio are the two most important variables determining the stability characteristics of the combustor. A slight increase in the inlet mixture tempe...

Performing high-fidelity simulations of complex reacting flows requires that the uncertainties associated with predictions of fundamental flame properties are characterized and minimized. Although the kinetics of C1-C4 hydrocarbon flames have been studied extensively in numerous past investigations, notable uncertainties exist. In the present study, the types of hydrocarbon fuels with the great...

A situation in which a diffusion flame reaches an end at some position in a medium of non-premixed reactants is studied. The mixing of reactants that takes place ahead of the diffusion flame leads to the formation of a "triple-flame", a structure which consists of a fuel-rich premixed flame, a fuel-lean premixed flame. and a diffusion flame that starts where the two premixed flames meet. An imp...

An idealized model for turbulent premixed flames is introduced. It consists of a scalar advection-reaction-diffusion equation that describes the interaction of a thin flame with a turbulentlike flow field acting on two separate scales. Rigorous asymptotic results as well as affordable and reliable direct numerical simulations are available to predict the effective large scale behavior of the id...

This research addresses the flame structure of single aluminum particles burning in air with the emphasis on the transition from spherically symmetric to non-symmetric combustion regime. The unique feature of this work is that free motionless aluminum particles were produced and ignited in both normal and microgravity environments. That allowed us to observe whether the particle flame non-symme...

The pulse-burst duration of a compact burst-mode Nd:YAG laser is extended by one order of magnitude compared to previous flashlamp-pumped designs by incorporating a fiber oscillator and diode-pumped solid-state amplifiers. The laser has a linewidth of <2 GHz at 1064.3 nm with 150 mJ per individual pulse at 10 kHz. The performance of the system is evaluated by using the third-harmonic output at ...

This paper outlines a theoretical approach for predicting the onset of detonation in unconfined turbulent flames. Two basic assumuptions are made: 1) the gradient mechanism is the inherent mechanism that leads to DDT in unconfined conditions, and 2) the sole mechanism for preparing the gradient in induction time is by turbulent mixing and local flame quenching. The criterion for DDT is derived ...