Improving gas turbine performance through optimization of combustor turbulence

In the age of global warming, rising fuel costs, and depleting natural resources, focus is placed on increasing the fuel sustainability and efficiency of the modern jet engine. Combustor turbulence significantly impacts losses in the downstream turbine, accounting for a 1.1\% decrease in stage efficiency. Here, the turbulence field at the combustor-turbine interface is optimized through modifications to the combustor geometry. We expect that the size, orientation, and positioning of the combustor jets can be modified to promote small-scale turbulence, remove the presence of Reynolds stress, and reduce anisotropy, all of which contribute to a decrease in boundary layer losses in a turbine blade-row. First, baseline characterization of combustor turbulence against measurements conducted with a combustor simulator is made with an Improved Delayed Detached Eddy Simulation. This model is simplified to enable rapid optimization of the geometry through coarsening of the mesh and increasing the timestep. Both gradient-based and Pareto-based approaches are explored to minimize turbulence intensity at the combustor-turbine interface and maximize mixing uniformity. We conclude with some recommendations for combustor geometry modifications that can lead to improved turbine performance.