Numerical Investigation on Unsteady Flowfield of Turbine Stage

The unsteady flowfield of the turbine stage are investigated numerically,the mechanism of the unsteady interaction between the rotor and the stator is discussed.Results show the fluctuation at high frequency has little effect on the flow unsteadiness,the fluctuation at the Blade Passing Frequency dominates the unsteady flow,and the variation of the force on the blade can be expressed by the sinusoidal function.The time averaged effect and the effect at the Blade Passing Frequency are uniform.The most strong fluctuation in the stator wake occurs at the middle of the rotor passage,and its unsteady effect mainly displays near the leading edge.