Effects of cooling-air injection on secondary flows and losses in a turbine cascade

摘要

In this paper, to investigate the overall performance and internal flows of air-cooled turbine blade rows, internal flows in a linear cascade model are examined using secondary air injections originating from various points located along of the turbine surfaces. Consequently, it was found that this secondary air flow interacted with the cascade passage vortices and significantly changed the loss distribution. In addition, it was illustrated that the cascade overall energy loss decreased when the air was injected along the mainstream flow. On the other hand, it was also shown that the energy loss increased when the air was injected against the mainstream flow from several points on the blade leading edge. Furthermore, the effects of cooling-air injection on the overall kinetic energy of the secondary flows and on the cascade outlet angle are discussed. In this discussion, only one loss coefficient is defined and used.