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 2D 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.

Development of 1D Model of Constant-Volume Combustor and Numerical Analysis of the Exhaust Nozzle

“…Fernelius et al [20] demonstrated experimentally that the full-annulus pulsation of an axial turbine deteriorated its efficiency, while the variation of the incidence angle [21] was the major performance parameter. Moreover, they tried to map the turbine's efficiency under pulsation [22] in order to offer recommendations for the design of these pioneering turbine airfoils [23]. Paniagua et al [24] investigated the peculiar flow field of a supersonic axial turbine when the transition of the subsonic to supersonic regimes occurs, mimicking the behaviour of the RDC's outflow.…”