Flame acceleration and deflagration-to-detonation transitions (DDT) in large obstructed channels filled with a stoichiometric methane–air mixture are simulated using a single-step reaction mechanism. The reaction parameters are calibrated using known velocities and length scales of laminar flames and detonations. Calculations of the flame dynamics and DDT in channels with obstacles are compared...

The characteristics of lifted laminar triple flames in the near field of the burner exit are experimentally and numerically investigated. The flames are established by introducing a nitrogen-diluted rich mixture of methane and air from an inner tube and a lean mixture from a concentric outer tube. The temperature and major species concentrations are measured using thermocouples and gas chromato...

Edge flames were investigated in a methane/O2/N2 counterflow diffusion flame burner. In a typical experiment, a stable counterflow diffusion flame in an axysymmetric configuration was perturbed by lowering the relevant Damköhler number slightly below the extinction value, Daext. As a result, the flame extinguished in the vicinity of the burner axis where conditions were uniform. An edge flame e...

The general objective of this project is to support the development and validation of large eddy simulation (LES) models used to simulate the response of fires to the activation of suppression systems. The focus here is on suppression by gaseous agents. The present experimental configuration is a two-dimensional, plane, buoyancydriven, methane-fueled, turbulent diffusion flame with a controlled...

Direct Numerical Simulations (DNS) have been conducted to study the response of initially laminar spherical premixed methane–air flame kernels to successively higher turbulence intensities at five different equivalence ratios. The numerical experiments include a 16-species/25-step skeletal mechanism for methane oxidation and a multicomponent molecular transport model. Highly turbulent condition...

The objective of this work is to quantitatively study the burning characteristics of thermoplastics. A new experimental setup with a T-shape trough is designed. Based on this setup, the loop mechanism between the wall fire and pool fires induced by the melting and dripping of thermoplastic can be well simulated and studied. Additionally, the flowing characteristics of pool fires can also be qua...

Two new 14-step and 16-step reduced mechanisms for methane-air combustion were developed with the emphasis on their capabilities to predict NO2 formation. The systematic reduction was carried out by assuming the quasi-steady state for 26~28 species in the starting mechanism with the help of a automatic mechanism reduction code. The two reduced mechanisms reproduce NO2 formation behaviors obtain...

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 ...