Design of a Pulsing Flow Driven Turbine

Abstract

There is widespread interest in using pressure gain combustion in gas turbine engines to increase gas turbine engine efficiency and reduce fuel consumption. However, the fluctuating turbine inlet conditions inherent with pressure gain combustion cause a decrease in turbine efficiency. Designing a turbine for pulsing flow would counteract these losses. An optimization of turbine geometry for pulsing flow was conducted with entropy generation as the objective function. A surrogate model was used for the optimizations based on data extracted from two-dimensional computational fluid dynamics simulations. Optimizations run for different pulsing amplitudes informed a revised turbine design. The new turbine geometry was validated with a periodic, time-accurate simulation, and a decrease in entropy generation of 35% was demonstrated. The design recommendations were to weight the design of the turbine toward the peak of the pressure pulse, to consider the range of inlet angles and decrease the camber near the leading edge, and to reduce the blade turning.