Degree Type

Dissertation

Date of Award

1993

Degree Name

Doctor of Philosophy

Department

Mechanical Engineering

Abstract

A baseline supersonic throughflow fan has been designed and tested at the NASA Lewis Research Center in order to demonstrate proof-of-concept and provide an experimental data base for this unique type of turbomachine. The aerodynamics of the rotor, which was tested in both an isolated and a stage configuration, is discussed in somewhat generic terms for conditions covering most of the practical operating range. Much detailed and quantitative information is also included. In addition to the experimental results, viscous computational fluid dynamics (CFD) results and simple analytical solutions are discussed, having been used extensively to understand and assess the aerodynamic performance of the rotor and to understand and interpret the experimental results. In general, most of the operational and performance characteristics for steady-state rotor operation can be explained and quantified using the various analytical methods;The experimental rotor performed much as designed, and off-design operation involved stable operational characteristics with no unusual instabilities, even during transitional phases of operation where transient discontinuities traversed the rotor now field. Rotor inflow starting, involving the propagation of a normal shock wave into the rotor from upstream, was accompanied by only minor discontinuities in rotor performance and blade loading;Two- and three-dimensional viscous CFD simulations for several rotor operating points exhibited good agreement with the experimental data. The lack of harsh dynamic effects on rotor blade loading and performance during rotor inflow starting was also predicted using the analytical methods;The application of a simple total-pressure loss model in conjunction with the experimental and CFD results allowed a fairly accurate determination of the first-order loss sources and their magnitudes for a wide range of operating conditions. For design-point operation it is shown that viscous losses account for about 51 percent of the total mixed-out loss, bow shock wave losses account for about 44 percent, and oblique shock losses contribute the remaining 5 percent. Mixing losses, which are included as part of the viscous and the bow shock losses in the simple model, account for about 28 percent of the total mixed-out loss.

DOI

https://doi.org/10.31274/rtd-180813-13472

Publisher

Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/

Copyright Owner

Daniel Lawrence Tweedt

Language

en

Proquest ID

AAI9941784

File Format

application/pdf

File Size

323 pages

Share

COinS