Accession Number : AD0427072

Title :   RESEARCH ON UNSTEADY STALL OF AXIAL FLOW COMPRESSORS.

Descriptive Note : Final rept., Dec 62-Nov 63.

Corporate Author : CORNELL AERONAUTICAL LAB INC BUFFALO N Y

Report Date : NOV 1963

Pagination or Media Count : 82

Abstract : An experimental and analytical program has been undertaken to investigate the basic flow processes underlying the phenomenon of rotating stall in axial flow compressors. The complete investigation encompasses both the behavior of the unsteady boundary layer on the blade elements and the study of flow conditions upstream and down stream of a cascade or compressor stage which are consistent with a disturbance of the rotatings/ll type. An experimental program is described which provided laminar boundary-layer velocity profiles near separation on a rotating cylinder. The cylinder was shrouded to impose an airfoiltype pressure gradient. A comparison between the experimental profiles and those predicted by a Pohlhausen-type quartic profile for a downstreammoving wall showed relatively good agreement, although the Pohlhausen analysis cannot be used to predict the separation point even approximately unless the wall velocity is very small relative to the velocity at the outer edge of the boundary layer. The data are compared to some previously published shadowgraph-smoke data obtained on the same apparatus. The comparison confirms that there is a downstream displacement of the separation point which is roughly linear in wall velocity when the wall is moving downstream. The magnitude of this displacement was larger in the present work than that inferred from the smoke data. (Author)

Descriptors :   (*AXIAL FLOW COMPRESSORS, STALLING), BOUNDARY LAYER, LAMINAR BOUNDARY LAYER, TURBOJET ENGINES, SEPARATION, PRESSURE, THEORY, VELOCITY, VORTICES, DIFFERENTIAL EQUATIONS, ROTATION

Distribution Statement : APPROVED FOR PUBLIC RELEASE