Influence of blade tip clearance on performance of multistage compressors

Multistage compressor is the most important component of gas turbines used in oil and gas industries, marine and aeronautical applications. Performance of gas turbines depends mainly on its multistage axial flow compressor. This paper mentions to a study on influence of tip clearance of rotor blades and the case to pressure ratio and performance of multistage axial compressors. The study is conducted by CFD (Computational Fluid Dynamics) method. CFD is conducted with changing the tip clearance of rotor blades and the case of a three stage axial air compressor. Result from the study shows that the smaller value of the tip clearance of the rotor blades and case, the greater of the pressure ratio generated and the higher the performance of the air compressor. However, in this study, the authors have not evaluated the vibration effect to the rotor tip baldes of the compressor when the tip clearance of the rotor blade and case is changed. The vibration could be considered as a factor that needs to be evaluated in designing and manufacturing air compressors. This factor may affects to the choice of materials and technology for air compressor manufacturing to avoid the impact of the tip of the rotor blades and the case while the compressor operates due to blade vibration in a small tip clearance.