Blade-row interaction in a high-pressure turbine

This paper presents a study of the three-dimensional flowfield within the blade rows of a single-stage high-pressure axial turbine (low-speed, large-scale), Measurements have been performed in the stationary and rotating frames of reference. Time-mean data have been obtained using five-hole pneumatic probes. The transport mechanisms of the stator wake and passage vortices through the rotor blade row have been studied using smoke flow visualization. Furthermore, unsteady measurements have been carried out using a three-axis hot wire. steady and unsteady numerical simulations have been performed using a structured three-dimensional Navier-Stokes solver to further understand the blade-row interactions, The transport of the stator viscous flow through the rotor blade-row is described, The rotor passage vortices are affected by the transport of the stator secondary Row. It is observed that the stator secondary flow vortices are convected through the downstream rotor blade-row in a similar but not identical way to the wake, At the hub the kinematic interaction between the stator and the rotor passage vortices has two effects, First, the suction side leg of the stator passage vortex is displaced radially upwards over the developing rotor passage vortex at the hub, Additionally, the pressure side leg of the stator passage vortex is entrained into the rotor passage vortex. The predicted flowfield was interrogated from the perspective of loss production. The contribution of the unsteady flow to the stage loss has been evaluated using unsteady numerical simulations, The effect of stator viscous Row transport on the rotor Row angles is also discussed in brief, Finally, a kinematic model is proposed for the transport of the secondary-flow vortices in the downstream blade-row based on the understanding obtained from the measurements and numerical simulations.