Flow Field and Wall Temperature Measurements for Reacting Flow in a Lean Premixed Swirl Stabilized Can Combustor

Abstract

Designing gas turbine combustors requires accurate measurement and prediction of the violent, high-temperature environment in reacting flow. One important factor in combustor design is the heat load on the inner surface of the combustor liner during combustion. To properly analyze the heat load, the mechanisms of thermal energy transfer must be investigated. Of these, the convective heat transfer has not been fully characterized, representing an important challenge in the field of combustor research. The flow field is closely related to the combustion dynamics from the swirling flame in modern burners, and has a direct impact on the convective heat transfer. Most of the flow field measurements reported in the literature have relied on custom research nozzles. However, the development of modern low emission, lean-premixed combustors requires experimental results from realistic industrial fuel nozzles. This paper experimentally investigates the effects of combustor operating conditions on the reacting flow in an optical single can combustor. The swirling flow was generated by an industrial lean pre-mixed, axial swirl fuel nozzle manufactured by Solar Turbines Incorporated. Planar particle image velocimetry (PIV) data were acquired and analyzed to understand the characteristics of the flow field. Experiments were conducted at Reynolds numbers ranging between 50000 and 110000 (with respect to the nozzle diameter, DN); equivalence ratios between 0.55 and 0.78; and pilot fuel split ratios of 0 to 6%. Characterizing the impingement location on the liner, and the turbulent kinetic energy (TKE) distribution were a fundamental part of the investigation. Self-similar characteristics were observed at reacting conditions. Jet impingement locations on the liner were at x ≈ 1.16 DN for seven different reacting cases, and it was observed that the impingement location was not significantly affected by the combustion parameters studied. However, non-reacting flow was significantly different in flame structure and impingement locations. Combustor liner wall temperature distributions were measured in reacting condition with an infrared camera for a single case. The temperature profile was explained qualitatively with the flow features measured with PIV. Peak wall temperature close to impingement location on the liner wall reached about 900 K, and peak heat flux was measured as ≈ 23 kW/m2 at x ≈ 2.3 DN.