Investigation of unsteady combustion of methane-air flame in a model combustion chamber with swirling flow

The present paper reports on the investigation of unsteady combustion of a methane-air mixture, including combustion at increased pressure in the combustion chamber and increased temperature of mixture heating for a model gas-turbine swirl burner based on a design by Turbomeca. To measure the velocity and OH fluorescence fields in the flows a combination of stereoscopic PIV and acetone PLIF systems is used. In all cases, the flow dynamics is associated with the movement of large-scale vortex structures in the inner and outer mixing layers and the flow structure corresponds to a swirling jet with a central recirculation zone containing combustion products. An increase in the heating temperature of the mixture and pressure in the combustion chamber leads to a periodic partial separation of the flame from the model swirl nozzle. However, the flow of fuel through the central channel will stabilize the flame.

Single-shot two-dimensional multi-angle light scattering (2D-MALS) technique for nanoparticle aggregate sizing

The two-dimensional multi-angle light scattering (2D-MALS) technique has been extended for single-shot size measurements of soot aggregates in flames. Six cameras are used for instantaneous acquisition of the elastic scattering from the aggregates at different directions between 10 to 90$$^\circ$$ ∘ of a laser light sheet. Two diluted ethylene (50 and 60% by volume of $$\hbox {C}_2\hbox {H}_4$$ C 2 H 4 fuel diluted with inert $$\hbox {N}_2$$ N 2 ) coflow laminar diffusion flames with little flickering are used as proof of concept. Results of instantaneous, average and fluctuating 2D fields of the effective radii of gyration, which are expected to characterize the size of the aggregates, compare well with the literature, demonstrating the applicability of the proposed sizing method to weakly unsteady combustion processes.

NUMERICAL AND EXPERIMENTAL INVESTIGATIONS OF UNSTABLE COMBUSTION IN LOW-EMISSION GAS-TURBINE COMBUSTORS

The paper presents the calculation and experimental results for investigated unsteady combustion modes in low-emission combustors operating without flow swirling and developed by the present authors.