Nonuniform flow and aerodynamic forces in a turbine due to asymmetric tip clearance

With the existence of the asymmetric tip clearance, the flow fields of turbines become nonaxisymmetric, and the performances of the turbines will be influenced. Based on the two-coupled actuator-disk model (2CAD), an analytic study of flow redistribution in a turbine stage due to asymmetric tip clearance is presented. The turbine disk is modeled as a plane, and a semiempirical method is used to connect the inlet and outlet of the rotor blade. The model is evaluated using linear perturbation approximation and nonuniform flow and aerodynamic forces because asymmetric tip clearance is predicted. Furthermore, some effects of such flow nonuniformity are examined as well.