Investigation of Sweep Applied to Rotating Axial Cascades and Numerical Simulations of Flow

This paper presents an original approach regarding the application of sweep to rotating blade cascades. The justification for swept blades is given by its consequence, i.e. a reduction of local velocity (usually from supersonic/ transonic to subsonic regimes) such that the losses due to shock waves and/or boundary layer displacement and/or followed by reattachment are minimized. As study cases were considered a cascade blade, as well as forward and backward sweep of span-wise cross sections. The RANS model was used to describe the flow and a comparative study was conducted by using four turbulence models, i.e. Spalart-Allmaras, k-ε, k-ω and Reynolds Stress RST models. The CFD analysis was done with the FLUENT solver, with the settings for 2D case, implicit equations and double precision. The convergence was monitored such that the residuals should be minimized. The results of the numerical simulations of the flow are expressed as the distributions of Mach number (in relative flow, since it is a rotational frame), static pressure, static temperature and entropy, which have been presented comparatively, for each turbulence model and sweep study case, corresponding to the design rotational speed of 275 [m/s].