Design of a Pulsing Flow Driven Turbine

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.

Mapping Efficiency of a Pulsing Flow-Driven Turbine

Pressure gain combustion (PGC) shows potential to increase the cycle efficiency of conventional gas turbine engines (GTEs) if used in place of the steady combustor. However, a turbine driven by pulsing flow experiences a decrease in efficiency. An experimental rig was built to compare a steady flow-driven turbine with a pulsing flow-driven turbine. The pressure pulse was a full annular, sinusoidal pressure pulse. The experimental data showed a decrease in turbine efficiency and pressure ratio. The pressure pulse amplitude and not the frequency was discovered to be the cause for the decrease in turbine efficiency for the current experimental setup. The decrease in turbine efficiency was mapped with turbine pressure ratio and corrected amplitude to demonstrate how the efficiency of a turbine under pulsing flow conditions could be mapped.

Predicting Efficiency of a Turbine Driven by Pulsing Flow

One of the challenges of integrating pressure gain combustion into a gas turbine engine is that a turbine driven by pulsing flow experiences a decrease in efficiency. Computational fluid dynamic simulations validated with experiments showed that pulse amplitude is the driving factor for decreased turbine efficiency and not the pulsing frequency. A quadratic correlation between turbine efficiency and corrected pulse amplitude is presented. Incidence variation is shown to cause the change in turbine efficiency and a correlation between corrected incidence and corrected amplitude is shown to predict turbine efficiency.

Study on the Blood Flow with Rolling Manipulation of Traditional Chinese Massage

A 2D model of a blood vessel under rolling manipulation (RM) is presented. The numerical simulations of blood flow are based on lattice Boltzmann method. It is found thatRMcan increase the blood flow. DifferentRMfrequency () has different influence on flow. When the frequency is equal to the pulsing flow frequency,the average flow over one period is the largest. Streamlines diagrams in different time when are given. Vortexes can be seen in the region under the stenosis. The distributions of streamlines change periodically.