Effect of part sweep on axial flow compressor performance in the presence of circumferential casing grooves

Abstract

Modern axial compressors demand high performance and increased operating range. High performance is generally obtained by employing 3D design features, such as sweep and lean. To improve operating range, use of circumferential casing grooves is quite common. An extensive numerical study is carried out to understand performance change due to swept rotor blade on axial compressor performance and stall margin, in the presence of circumferential casing grooves. Numerical methodology used in the current work is validated with experimental data of NASA Rotor37. Grid sensitivity as well as turbulence model validation is carried out to validate numerical methodology used in this work. A baseline rotor is created without any sweep. Sweep considered in this study is employed only at part span of the blade. Impact of part sweep with circumferential casing grooves is not reported by many in open literature, which is the focus of this work. Different magnitudes of sweep are considered in this study. The current study indicates existence of an optimum combination of magnitude of sweep and span location at which sweep starts from. Sweep in the presence of circumferential grooves results in considerable increase of operating range with nominal decrease in efficiency. A detailed flow field investigation is presented to understand the underlying flow physics.