Computational and experimental study of a forced, time-dependent, methane–air coflow diffusion flame

摘要: Abstract Forced, time-varying flames are laminar systems that help bridge the gap between and turbulent combustion. In this study, we investigate computationally experimentally structure of a periodically forced, axisymmetric methane–air diffusion flame in which cylindrical fuel jet is surrounded by coflowing oxidizer jet. The forced imposing sinusoidal modulation on steady flow rate. Rayleigh spontaneous Raman scattering used to generate temperature major species profiles. Particle image velocimetry determine magnitude velocity at exit burner phase forcing modulation. CH∗ emission measurements provide an indication overall shape. Computationally, solve transient equations for conservation total mass, momentum, energy, mass with detailed transport finite rate chemistry submodels. governing written using modified vorticity–velocity formulation solved adaptively refined grid implicit time stepping Newton’s method nested Bi-CGSTAB iterative linear system solver. Results study include investigation start-up features time-dependent it takes initial transients dissipate. We description fluid dynamic-thermochemical 20 Hz frequency both 30% 50% perturbations. Comparisons determined calculated temperature, CO H2O mole fraction profiles verification accuracy model.