The Design and Performance of Axially Symmetrical Contoured Wall Diffusers Employing Suction Boundary Layer Control

Abstract

This paper presents a procedure for the design and the performance prediction of axially symmetrical contoured wall diffusers employing suction boundary layer control. An inverse problem approach was used in the potential flow design of the diffuser wall contours. Three short (L/l ≤ 5.15), high area ratio (2.5 and 3) diffusers were tested in the study and were found to have effectiveness values in excess of 90 percent (comparable straight wall diffusers have effectiveness <40 percent) while requiring suction flows of less than 10 percent of the inlet flow. The experimentally observed flow characteristics, the stability of flows within the diffusers, are also described. Because of their high effectiveness and short length these diffusers appear to be ideally suited for use as gas turbine combustor diffusers and as turbine discharge diffusers.

Time-Dependent Method to Solve the Inverse Problem for Internal Flows

“…The Stanitz solution has been extended to the axisymmetric potential flow by Nelson et al 2 Such solutions are based on the treatment of the potential and stream functions, therefore they are confined to the two-dimensional or axisymmetric potential flows.…”

Use of Subdomains for Inverse Problems in Branching Flow Passages

“…Yang and co-workers (Nelson et al, 1975 andYang, 1977) presented an inverse calculation procedure for ASME affiliation: 1-Student member, 2-Associate member, 3-Fellow incompressible, irrotational flows in axisymmetric circular and annular passages. The governing equations were transformed into a coordinate system where the velocity potential function and stream function were the independent variables.…”