Combustion and Emission Formation in the Stirling Engine with Exhaust Gas Recirculation 710824
The combustion and emission formation in continuous combustion burners have been studied both theoretically and experimentally.
The theoretical study is concerned with the combustion and emission formation in idealized sprays in quiescent air. The effects of the spray rotation and the air axial and radial velocities have been examined. A model has been developed for the emission formation in an actual Stirling engine. This model showed that the incomplete combustion products are primarily formed in the heterogeneous eddies zone near the burner walls. In this region, surface combustion takes place. The nitric oxide is primarily formed in the premixed-eddies zone where microvolume combustion is believed to take place.
The experimental results deal with the effect of diluting the charge by using excess air or exhaust-gas recirculation on performance and emissions. The emissions measured are the nitric oxide, carbon monoxide, unburned hydrocarbons, and carbon. The tests were conducted at 5 and 8 hp.
The effect of residence time in air preheater on the different emissions has been assessed. It was shown that the increase in residence time was effective at light loads and low air-fuel ratios in reducing exhaust emissions. Exhaust-gas recirculation was effective in reducing the nitric oxide emissions up to approximately 40 % recirculation. However, the thermal efficiency of the Stirling engine decreases with the increase in the percentage exhaust-gas recirculation.