We report the spatially resolved detection of methyl radicals in a methane-air flat flame, using degenerate four-wave mixing (DFWM). A frequency-tripled dye laser pumped with a frequency-doubled Nd:YAG laser was used to access the Herzberg beta(1) band of methyl near 216 nm. Using a nearly phase-conjugate geometry, we detected methyl with high spatial resolution [0.2 mm (0.3 mm) vertical (horiz...

The rapid formation of tungsten oxide nanorods through electron beam (EB) irradiation on the surface of micron-sized flame formed tungsten-oxide fragments is reported. The micro-sized fragments (precursor material) were formed in a counter-flow methane diffusion flame on the surface of a tungsten wire. Nanorods of various lengths and aspect ratios were rapidly formed in the surrounding area of ...

act— A CFD-based numerical model has been ed for the determination of the volume concentration ber density of soot in a laminar diffusion flame of in air, under transient condition following ignition of e. The transience is studied from the point of ignition final steady state is reached. The burner is an axiric co-flowing one with the fuel issuing through a port and air through an annular port...

The effect of a stabilized non-equilibrium gliding arc plasma discharge on the stabilization and extinction of nitrogen diluted, methane/air counterflow diffusion flames was investigated both experimentally and numerically. To quantify the effect, extinction limits and flame temperature profiles via Rayleigh scattering were measured, calculated and compared to numerical simulations using detail...

The Lagrangian Flamelet Model is formulated as a combustion model for large-eddy simulations of turbulent jet diffusion flames. The model is applied in a large-eddy simulation of a piloted partially premixed methane/air diffusion flame ~Sandia flame D!. The results of the simulation are compared to experimental data of the mean and RMS of the axial velocity and the mixture fraction and the unco...

We report on kilohertz-repetition-rate flame temperature measurements performed using blue diode lasers. Two-line atomic fluorescence was performed by using diode lasers emitting at around 410 and 451 nm to probe seeded atomic indium. At a repetition rate of 3.5 kHz our technique offers a precision of 1.5% at 2000 K in laminar methane/air flames. The spatial resolution is better than 150 microm...

A water mist jet for a steam generator of direct contact with a diffusion flame is numerically analyzed in this paper. Numerical simulation is conducted for an 8 Lug-Bolt array in a confined system. The diffusion flame is modelled in the Eulerian Eulerian multiphase approach where the reaction species are oxygen which is injected by a 16.9 mm central nozzle, methane by four peripheral 5.86 mm n...

In this paper we study the formation of NO in laminar, nitrogen diluted methane diffusion flames that are seeded with ammonia in the fuel stream. We have performed numerical simulations with detailed chemistry as well as laser-induced fluorescence imaging measurements for a range of ammonia injection rates. For comparison with the experimental data, synthetic LIF images are calculated based on ...

A computational study is performed to investigate the effects of mixture composition oscillations on a strained premixed methane/air flame. The problem is of practical relevance in direct-injection spark-ignition (DISI) engines and gas-turbines, in which premixed flames propagate through temporally and spatially stratified mixture field. The primary focus of the study is to identify the dynamic...

Dimethyl ether (DME) is considered a promising alternative to diesel fuel in compression-ignition engines because of low particulate and NOx emissions along with high thermal efficiencies as well as improved auto-ignition characteristics due to its high cetane number. Recently, DME also has been selected as a prospective fuel candidate for the validation of turbulent combustion models organized...