Dilution jets in a gas turbine combustor are used to oxidize remaining fuel from the main flame zone in the combustor and to homogenize the temperature field upstreamof the turbine section through highly turbulent mixing. The high-momentum injection generates high levels of turbulence and very effective turbulent mixing. However, mean flow distortions and large-scale turbulence can persist into the turbine section. In this study, a dilution hole configuration was scaled from a rich-burn-quench-lean-burn combustor and used in conjunction with a linear vane cascade in a large-scale, low-speed wind tunnel. Mean and turbulent flowfield data were obtained at the vane leading edge with the use of high-speed particle image velocimetry to help quantify the effect of the dilution jets in the turbine section. The dilution hole pattern was shifted (clocked) for two positions such that a large dilution jet was located directly upstream of a vane or in between vanes. Time-averaged results show that the large dilution jets have a significant impact on the magnitude and orientation of the flow entering the turbine. Turbulence levels of 40% or greater were observed approaching the vane leading edge, with integral length scales of approximately 40% of the dilution jet diameter. Incidence angle and turbulence level were dependent on the position of the dilution jets relative to the vane.
All Science Journal Classification (ASJC) codes
- Aerospace Engineering
- Fuel Technology
- Mechanical Engineering
- Space and Planetary Science