Axial Flow Rotor Unsteady Performance.
Abstract
Two problems facing designers of axial flow turbomachines at present are requirements for operation with increased efficiency and reduced radiated noise. To meet these requirements, it is necessary to have detailed information on the influence of geometrical and operating characteristics of blade rows on their unsteady response to distortions in the inflow velocity field. Unsteady response as defined here refers to the unsteady lift force and pitching moment generated on a rigid (i.e., nonvibrating) blade operating in a nonuniform, inviscid, incompressible flow. The unsteady pressure upon which the unsteady force and moment depends is also responsible for generation of part of the radiated acoustic or noise field. In this study, the objective was to investigate unsteady response. Thus, te acoustic problem was not treated in detail. However, a brief discussion is presented which shows how the results can be applied to define the related acoustic source field. In this study, an existing two-dimensional, nonviscous theory which employed a simplified vortex model in conjunction with the assumptions of thin airfoil theory to define cascade unsteady lift was modified and extended to include an expression for unsteady pitching moment. Computed theoretical results were compared with measured values of unsteady lift force and pitching moment coefficients and their phase angles and with the unsteady center-of-pressure position.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 14, 1979
- Accession Number
- ADA081107
Entities
People
- E. P. Bruce
Organizations
- Pennsylvania State University