The flow in turbomachines is three-dimensional and complex
due to the existence of flow vortices which are generated by the
deflection of the flow through the blade channels. If the tip
clearance exists, the flow field becomes more complex due to
tip leakage. In this study the flow field was investigated
experimentally and numerically. The experimental study was
carried out by using a calibrated five-hole probe. The
measurements were performed at different planes through the
blade axial chord. These planes were placed upstream of the
blades, through the blade channels and downstream of the
blades. The measurements were performed for different tip
clearance gaps. The three-dimensional flow was also obtained
by solving Reynolds Averaged Navier Stokes equations. The
eddy viscosity was calculated by using Shear Stress Transport
(SST) k-ω turbulence model. It was found that the leakage flow
rolls up due to the pressure difference between the blade
pressure surface and the blade suction surface and interacts
with the passage vortex forming the tip leakage vortex. The
numerical technique used here could predict the shape of the
passage vortex and the tip leakage vortex with good agreement
with the experimental measurement. The experimentally
measured and the numerically calculated losses were used to
examine previous published correlations of tip leakage loss.
Recommendations are given for the most accurate tip leakage
loss correlations.