Calculation procedure for three-dimensional turbulent flow in a centrifugal impeller with any blade geometry

A method for calculating 3-D turbulent flow in a centifugal impeller is developed by solving the incompressible, steady, time averaged N-S equation in general curvilinear coordinates. The K-ε two-equation turbulence model is utilized to describe Reynolds stresses. A calculation scheme is proposed which divides a centrifugal compressor impeller into three calculation zones, i.e. the inlet zone, the channel zone, and the exit-vaneless diffuser zone. A simple and time-saving method for generating 3-D body-fitted coordinate system of a centrifugal impeller is established by means of combining an algebraic transformation with the solution of 2-D elliptic partial differential equations. This method is applied to calculate the turbulent flow in an industrial centrifugal compressor impeller. The tendency of the 'jet-wake' formation and growth in the impeller can be clearly seen, and the secondary flow pattern calculated is similar to Eckardt's measurements. The calculation results at the impeller exit are also in good agreement with the experimental results performed by the authors.