Performance analysis of a micro pneumatic turbine using actual driving conditions simulation

Abstract

Currently, nearly all literature discussing the performance of a micro pneumatic turbine using computational fluid dynamics (CFD) adopts either single reference frame simulation (SRFS) or multiple reference frame simulation (MRFS), with previously specified inlet pressure, outlet pressure and rotation speed. The overly constrained boundary conditions prevent the simulations from obtaining the turbine performance accurately under actual driving conditions, leading to calculation errors. This article proposes actual driving conditions simulation (ADCS) to predict the performance of a micro pneumatic turbine. In this approach, the inlet and outlet pressures are specified, while the turbine inertia moment is set according to the physical model of the turbine. SST k-ω turbulence model and dynamic grid technology are used to compute intricately time-varying flow parameters for obtaining the performance of the turbine. The results of SRFS, MRFS, ADCS and theory calculation (TC) demonstrate that the torque of a micro pneumatic turbine increases with an increase in supply pressure. The average torque calculated by ADCS is closer to that of TC compared with SRFS and MRFS. Moreover, the relative error of rotation speed between ADCS and experiments ranges from 2% to 10.9%, which is lower than that of between TC and experiments at the same working conditions.