Preliminary Analysis On Recirculation Structure In Primary Zone And Related Lean Blowout Of The Swirl Cup Combustor

Gas turbine has the merits of low emissions, low noise, low maintenance costs, long repair cycle, and high power per unit volume, so it has wide application. As the problems of energy crisis and the limited environmental capacity becoming increasingly prominent, the utilization of medium and low heat value fuel has been very important, such as the pyrolysis oil, bio-gasification gas, bio-diesel, alcohols and ethers, and so on. However, the minimum ignition temperature of the medium and low heat value fuel is relatively high, and the lower combustion limit is also relatively high, which easily lead to extinction and poor combustion stability, so it is needed to do more and meticulous work for combustion organization and widing combustion stability range.This paper took gas turbine combustor with swirl cup dome as research object, based on the flow organization of the primary zone, focused on that the lean blowout has strong local features apparently, and took analysis for the flow field structure of the primary zone. The main contents are as follows:1. The experimental data of lean blowout fuel/air ratio of a single-dome swirl cup combustor with different inlet air velocities and temperature was obtained at atmospheric pressure conditions. Numerical simulations both burning and non-burning were performed corresponding to the experimental data at lean blowout. The effects of changes of the inlet air velocity and temperature on the recirculation zone's size, location and so on, have been analyzed. Through combining the simulation results with the corresponding experimental data, the reasons why the lean blowout fuel/air ratio varied with inlet air conditions' changes were analyzed.2. Numerical simulations for WR230 combustor's primary zone of pre-modeling and post-modeling were performed. The features of the combustor dome's flow structure were analyzed by comparing qualitatively. A cooling device was designed for combustor lid, and it played a role of protecting combustor's dome with effective result. These can provide reference for testing the lean blowout performance of the modeling combustor rig.3. A new swirl cup dome was designed to try to produce rich flow structure in primary zone. The fuel gas composed of 28% methane and 72% carbon dioxide was used. Numerical simulations were performed to analyze the differences of the flow structures in primary zone between the combustor with new swirl cup dome and the one with typical swirl cup dome. This research can provide reference for the design of new flame stabilizer and the improvement of the lean blowout performance.