Fuel spraying and mixing in a simulated combustion chamber in the presence of air flow precession

Numerical calculations of the flow downstream the flame tube of the combustion chamber in the conditions of nonstable flow are presented in the paper. The obtained velocity fields were used for the modeling of non-stationary nature of the flow. The comparison of the results of calculations carried out using this model with the results of calculations based on the fluent commercial packages showed their good agreement. It was found that the flow under consideration is essentially nonstationary, with signs of precession. Numerical calculations of liquid fuel droplet distributions in the area stimulating the configuration of the combustor liner were carried out. It was found that a significant portion of the fuel hits the walls of the chamber. The processes of atomization of fuel in a non-stationary precession jet flowing out of the chamber are investigated experimentally. It has been shown that the interaction of fuel jet with precession air flow gives a sufficiently homogeneous air-fuel mixture with an average droplet diameter of about 50 microns or less. Data on the dependence of the concentration distribution and droplet size on flow regimes of air and fuel have been obtained. It is shown that the base of the jet fuel in a swirling air flow under the influence of the vortex precession performs rotational - oscillatory movement. This process is visually observed only in conditions of pulsed illumination of the flow.