Effects of squealer rim height on aerodynamic losses downstream of a high-turning turbine rotor blade

Abstract

The effects of squealer rim height on three-dimensional flows and aerodynamic losses downstream of a high-turning turbine rotor blade have been investigated for a typical tip gap-to-chord ratio of h/c = 2.0%. The squealer rim height-to-chord ratio is changed to be h(st)/c = 0.00 (plane tip), 1.37, 2.75, 5.51 and 8.26%., Results show that as h(st)/c increases, the tip leakage vortex tends to be weakened and the interaction between the tip leakage vortex and the passage vortex becomes less severe. The squealer rim height plays an important role in the reduction of aerodynamic loss when h(st)/c <= 2.75%. In the case of h(st)/c >= 5.51%, higher squealer rim cannot provide an effective reduction in aerodynamic loss. The aerodynamic loss reduction by increasing h(st)/c is limited only to the near-tip region within a quarter of the span from the casing wall. (C) 2008 Elsevier Inc. All rights reserved.