Numerical investigation on the unsteady flowfield of the turbine stage under different axial gaps

The unsteady flowfield of the turbine stage were investigated numerically under different axial gaps, and the influence of the axial gap on the flow unsteadiness and the flowfield was discussed. Results show the axial gap L has great influence on the flow unsteadiness in the rotor. The intensity of the stator wake and its influence range increase with the reduction of the axial gap, and the unsteady influence of the stator wake mainly occurs near the leading edge of the rotor. The turbulent kinetic energy of the rotor outlet is minimum under the half of the design axial gap because the recovery effect of the stator wake is directly proportional to the wake intensity of the incoming flow.