EFFECT OF ROTOR BLADE TIP CLEARANCE ON TIP LEAKAGE-SECONDARY FLOW INTERACTION IN A TRANSONIC AXIAL COMPRESSOR

Ayesha Khan M

Abstract


Numerical simulations of a single stage low aspect ratio transonic axial flow compressor (NASA37) have been carried out at zero rotor tip clearance, design rotor tip clearance and twice the design rotor tip clearance with two higher and two lower rotor blade solidities. The objective was to assess the fluid flow interaction between tip leakage flow and secondary flow, and its effect on compressor performance. The tip leakage flow initiates near the rotor blade leading end, crosses the passage shock and interacts with the secondary flow vortex present at the pressure surface of the neighbouring blade near leading edge. The interaction becomes stronger with larger tip clearance and results in a low momentum fluid zone near the pressure surface in the rear part of the rotor blade. The blockage caused by this retarded fluid zone seems to be responsible for performance degradation of the compressor stage. The peak stage pressure ratio and peak Isentropic efficiency reduce by 3.6% and 2% respectively when the tip clearance is increased from zero to twice the design value. Similarly, the compressor performance decreases with increase in solidity from low to high solidity.

Keywords


Transonic, Tip Clearance, Solidity, Secondary flow

Full Text:

PDF

Refbacks

  • There are currently no refbacks.