Influences of slotted blade on performance and flow structure of a transonic axial compressor

Abstract

Main reason of compressor instability is boundary layer separation on the surface of blades. As one of flow control methods of the compressor, slotted blade has attracted many researchers’ attention because of its simple geometric structure and remarkable flow control effect. In order to evaluate its availability in the compressor, a type of convergent slot is designed to implement in a single-stage transonic axial compressor. Three configurations, i.e. rotor slot, stator slot and rotor-stator combined slot, are introduced to study the aerodynamic performance of compressor by numerical simulations. Furthermore, flow structures have been analyzed to explain the corresponding mechanism. The results show that overall stability margin of the compressor has been improved by flow control with slotted blade. Behavior of the rotor slot is better than that of the stator slot, but due to mass flow leakage in the slot, peak efficiency and chocking mass flow rate of the compressor are decreased by 1.18% and 3.8% respectively. The low momentum flow on pressure surface is sucked into the jet slot of stator blade, which improves the overall stability margin of 0.63%. The combined scheme with slotted rotor and slotted stator has obtained the best aerodynamic behavior with the increase of the overall stability margin of 2.83%. During the future research, main goal will be improvement of the compressor performance and extension of the mass flow rate range.

Numerical investigation on the influence of nonuniform tip clearance on rotor tip-clearance flow field structure

“…Active control techniques include boundary-layer suction, end-wall air injection, and casing suction [ [5] , [6] , [7] ]. Passive flow-control methods include casing treatments, slotted blades, and curved/swept blades [ [8] , [9] , [10] , [11] ]. Notably, the aforementioned flow-control method in the tip-clearance area requires substantial modifications to the compressor structure and internal aerodynamic layout, resulting in higher costs.…”