Accession Number:

ADA214687

Title:

Multistage Axial-Flow Turbomachine Wake Production Transport and Interaction

Descriptive Note:

Final rept. 1 Sep 1975-31 Dec 1978

Corporate Author:

IOWA STATE UNIV AMES ENGINEERING RESEARCH INST

Personal Author(s):

Report Date:

1979-02-01

Pagination or Media Count:

9.0

Abstract:

Procedures and instrumentation for acquiring time-average slow response average of continuously sampled data and periodic-average electronic and arithmetic average of periodically sampled data flow field data between blade rows of a research turbomachine were developed. Slow and fast-response total pressure probes and hot-wire anemometry were involved. A special 5 microsec sampling and holding circuit that could be phase locked to reference rotor blade position was designed and built. Two-dimensional time-average and three-dimensional periodic-average velocity vector information was obtained. Observed time-average flow patterns involved appreciable circumferential variations behind both rotors and stators and they could be changed significantly by circumferentially shifting upstream stationary blades. Observed periodic-average flow patterns showed that rotor and stator flow fields are 3- dimensional as well as periodically unsteady. A simple wake chopping transport and interaction model based on experimental data proved to be an excellent means for organizing and explaining data trends. Variations of periodic-average flow patterns with rotor sampling position could be understood in terms of the wake chopping, transport and interaction model proposed. Compressor inlet noise measurements indicated that blade-passing frequency noise level could be changed substantially with appropriate stationary blade row circumferential positioning when the same number of blades was present in each stationary blade row and when the spinning blade interaction pattern speed was above the cut-off amount.

Subject Categories:

  • Fluid Mechanics
  • Jet and Gas Turbine Engines

Distribution Statement:

APPROVED FOR PUBLIC RELEASE