Effects of nozzle spacing on lean blowout performance and flow fields

In order to deepen understanding of the influence of nozzle spacing on lean blowout and aerodynamic performance of gas turbine combustor, a dual-head model combustor with continuously adjustable nozzle position was designed based on the typical dual-stage swirling diffusion nozzles. The maximum flame propagation spacing between nozzles was measured and the dynamic process of flame propagation was analyzed with different initial equivalent ratios. Additionally, the effects of nozzle spacing on the lean blowout equivalent ratio, reacting flow field and root mean square velocity field were studied. The experimental results show that: with the increase of the equivalent ratio of 0.1, the dimensionless maximum flame propagation spacing increases by about 0.2,and the flame propagation process between nozzles can be roughly divided into four stages. The lean blowout equivalent ratio of single nozzle is bigger than that of double nozzles with arbitrary nozzle spacing. As the double nozzles spacing decreases, the lean blowout equivalent ratio first decreases and then increases. In addition, the decrease of nozzle spacing leads to jet mergence, decrease of radial velocity, increase of central jet velocity peak and decrease of size of central recirculation zone.As the nozzles move close to each other, the value and distributionarea of root mean square velocity between nozzles become larger and wider.