Ignition and burning of the composite sample impacted by the Bunsen burner flame : a fully coupled simulation

Experimental study and three-dimensional simulation of warming up, ignition, and subsequent burning out of the composite material impacted by the attached Bunsen burner flame is presented. The specimen is the fiberglass-reinforced composite with the epoxy resin binder. In the experiment, vertical specimen was located above the laminar diffusion flame, and transient variation of specimen mass and surface temperatures was recorded until the matrix polymer burned out. In the simulations, thermal decomposition of the composite was evaluated by the in-house pyrolysis model Pyropolis coupled with the general-purpose CFD solver, which simulated the flames generated by the burner and by the combustible volatiles. Formal kinetics of thermal decomposition of matrix polymer and the heat of combustion of volatiles have been derived from the microscale combustion calorimetry measurements. The simulation results include favorable comparisons of experimental and predicted dynamics of material degradation and flame behavior. Transient spatial distributions of surface temperature, burning rate, and heat fluxes (net, radiative and convective) are demonstrated. This study is the step towards developing the computational framework capable of replicating and predicting the outcome of standard fire tests UL94 and VBB

Formation and destruction of nitric oxide in methane flames doped with NO at atmospheric pressure

A study of formation and destruction of NO in adiabatic laminar premixed flames of CH4 + O2 mixtures diluted with N2 or Ar (with various dilution ratios) in a range of equivalence ratios at atmospheric pressure is presented. Nitric oxide was seeded into the flames using mixtures of diluent gas + 100 ppm of NO. The heat flux method was employed to measure adiabatic burning velocities of these flames. Nitric oxide concentrations in the post-flame zone at 10, 15 and 20 mm above the burner surface were measured using probe sampling. Burning velocities and NO concentrations simulated using a previously developed chemical kinetic mechanism were compared with the experimental results. The conversion ratio of NO seeded into the flames was determined. The kinetic mechanism accurately predicts burning velocities over the range of equivalence ratios and NO conversion in the rich flames. Significant discrepancies between measured and calculated NO conversion in the lean and near-stoichiometric flames were observed and discussed

Formation and destruction of nitric oxide in methane flames doped with NO at atmospheric pressure

A study of formation and destruction of NO in adiabatic laminar premixed flames of CH4 + O2 mixtures diluted with N2 or Ar (with various dilution ratios) in a range of equivalence ratios at atmospheric pressure is presented. Nitric oxide was seeded into the flames using mixtures of diluent gas + 100 ppm of NO. The heat flux method was employed to measure adiabatic burning velocities of these flames. Nitric oxide concentrations in the post-flame zone at 10, 15 and 20 mm above the burner surface were measured using probe sampling. Burning velocities and NO concentrations simulated using a previously developed chemical kinetic mechanism were compared with the experimental results. The conversion ratio of NO seeded into the flames was determined. The kinetic mechanism accurately predicts burning velocities over the range of equivalence ratios and NO conversion in the rich flames. Significant discrepancies between measured and calculated NO conversion in the lean and near-stoichiometric flames were observed and discussed

Kinetics and mechanism of chemical reactions in H2/O2/N2 flames at atmospheric pressure

The kinetics and mechanism of chemical reactions in the H2/O2/N2 flame were studied experimentally and by simulating the structure of premixed laminar flat atmospheric H2/O2/N2 flames of different initial compositions. The concentration profiles for stable compounds (H2, O2, and H2O), H atoms, and OH• radicals in flames were measured by molecular-beam sampling mass spectrometry using soft electron-impact ionization. The experimental data thus obtained are in good agreement with the results of simulations in terms of three familiar kinetic mechanisms, suggesting that these mechanisms are applicable to the description of the flame structure in hydrogen-oxygen mixtures at atmospheric pressure