Experimental Investigation of a Novel Combustor Modelfor Gas Turbines

Abstract

The present study describes the performance of a novel combustor model for gas turbines. The working principle of this combustor is based on the establishment of a large recirculation zone in the combustion chamber, where part of the inlet air is mixed with the combustion products. Efficient mixing is achieved by the use of high-velocity inlet air jets. Six different inlet air geometries have been analyzed under nonreacting and reacting conditions at atmospheric pressure. Laser-Doppler anemometry was employed to characterize the mean velocity and turbulent kinetic energy fields as a function of the air mass flow rate and geometry configuration. Measurements of mean gas species concentration (O 2 , CO 2 , CO, HC, and NO x ) at the model exhaust are reported as a function of the equivalence ratio for all configurations. The isothermal data revealed that the recirculation ratio is mainly a function of the geometry, with a minor dependence on the experimental conditions. Under reacting conditions, the data revealed that NO x emissions are low regardless of the combustor operating conditions and geometry. However, the air inlet configuration has a strong effect in combustor efficiency.