The three-dimensional viscous unsteady Reynolds-averaged Navier-Stokes equations were solved to simulate the flow on a low pressure turbine blade. The effects of synthetic jet on the flow separation in the suction side of the Pak-B low pressure turbine blade were numerically investigated by the SST(shear stress transport)turbulence model coupled with the Langtry-Menter transition model for turbulent flow. The unsteady flow control mechanism of synthetic jet and the flow structure were also presented. The numerical results show that the flow separation in the blade suction side can be effectively suppressed even eliminated by introducing the synthetic jet with the proper control frequency. At the Reynolds number of 25 000 and the free stream turbulence intensity of 0.08%
the increase in synthetic jet frequency can improve the control effectiveness of the flow separation on the low pressure turbine blade and reduce the flow loss. When the synthetic jet frequency is 10 Hz
the flow loss coefficient relative to the total pressure at the turbine blade exit is 0.42. However
the relative loss coefficient decreases to only 0.41 when the synthetic jet frequency increases to 20 Hz. These results imply that the flow loss does not drop clearly for the low pressure turbine blade at low Reynolds number when the synthetic jet frequency is greater than 10 Hz.
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references
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