The effects of low-profile vortex generators on flow in a transonic fan-blade cascade

Abstract

Two dimensional fully-mixed-out flow conditions were measured downstream of a two-passage transonic fan-blade cascade which had low-profile vortex generators (VGs) attached to the suction surfaces of the blades. The simulation was conducted using a blowdown wind tunnel at a Mach number of 1.4. The objective was to assess the effects of vortex generating devices on the suction surface shock-boundary layer interaction and the resulting losses. Measurements are reported from tests made with older aluminum blading, with and without VGs, and with a nominally similar new set of steel blading, with and without VGs. Differences between the old and new blading were found to be most significant. While shock structures appeared to be similar with VGs attached, dye injection showed that the shock-induced boundary layer separation was greatly suppressed and the downstream flow was much steadier. With VGs, the flow turning was improved by 0.94 degrees, but the flow loss coefficient increased by about 8%. An extension of the study is needed to fully assess the potential of using low-profile VGs in military fan engines.