Two-dimensional simulation of circulation control turbine cascade

摘要

The application of Coanda effect to turbine was first studied in this article through two-dimensional numerical simulation of circulation control turbine cascades. The influence of the aerodynamic and geometric parameters, such as the supply pressure of jet, the slot height, the shape, and curvature of the Coanda surface, on the performance of the circulation control turbine cascade was investigated in detail. The results show that the circulation control turbine cascade can achieve and exceed the performance level of the original turbine cascade (the baseline) at the cost of an acceptable jet supply pressure. The aerodynamic performance of circulation control turbine cascades is largely determined by two critical factors: the velocity of jet and the curvature of the Coanda surface. Low magnitude of jet velocity and large curvature of Coanda surface near the jet exit would lead to a serious jet detachment that is generally responsible for less flow turning and high energy loss. The jet attachment to the Coanda surface with a large curvature can be obtained only when the jet speed is high enough. Also, at this time, circulation control turbine cascade can bring a large flow turning but also a high energy loss based on a modified definition of the energy loss coefficient.