Accession Number:

ADA158094

Title:

Analysis of the Effects of Transient Heat Transfer on Axial Flow Compressor Blade Boundary Layers.

Descriptive Note:

Master's thesis,

Corporate Author:

AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH

Personal Author(s):

Report Date:

1985-06-01

Pagination or Media Count:

69.0

Abstract:

This thesis determines the magnitude of heat transfer in the high-pressure compressor of a turbofan engine during a Bodie throttle transient and estimates the effect of transient heat transfer on compressor blade boundary layer growth. Total stored thermal energy available for release is determined considering compressor blades and roots only. Thermal energy released during a throttle transient is determined and allocated to individual compressor stages and used to estimate blade heat flux. The average heat transfer coefficient at the maximum heat transfer rate is also calculated. A simple boundary layer analysis is performed assuming zero pressure gradient, compressible turbulent flow over a flat plate. Under free-stream conditions similar to those in the tenth stage of the compressor, this analysis shows increased boundary layer displacement thickness with heat transfer. In zero pressure gradient, the displacement thickness change with heat transfer is small, as is the change in flow deviation angle at the trailing edge of the compressor blade. Heat transfer coefficients are also calculated in the boundary layer analysis and agree with results from the experimental heat transfer allocation procedure to within 30. Results of boundary layer analysis indicate assumptions made in heat transfer allocation procedure are reasonable and that simple boundary layer analysis with the absence of modifying pressure gradients provides a good first estimate of heat transfer effects on blade boundary layers.

Subject Categories:

  • Fluid Mechanics
  • Thermodynamics
  • Jet and Gas Turbine Engines

Distribution Statement:

APPROVED FOR PUBLIC RELEASE