Hydrodynamic Effects on Heat Transfer for Film-Cooled Turbine Blades.
Abstract
The objectives of this project were to develop a technique for generating very high freestream turbulence levels and to determine resulting effects on turbulent boundary layer and film cooling flows. Also, included in this project was the development of a simultaneous temperature/velocity measurement technique. All of these objectives were accomplished as described below; however, film cooling flows were studied only for minimal freestream turbulence levels. Several turbulence generating devices were studied to determine the maximum turbulence levels. Tests indicated that high velocity jets in cross-flow generated turbulence levels, Tu, which ranged from Tu = 20% to 11% over a 0.65 m distance. The turbulence integral length scales for this flow were on the order of boundary layer thickness. High freestream turbulence levels caused significant increases in surface heat flux. Various correlations for freestream turbulence affects on surface heat flux were evaluated. None of these correlations were adequate; however, with slight modifications two of the correlations reasonably collapsed the data. Thermal field measurements of simulated film cooling flows with a minimal freestream turbulence level indicated that the jet detachment/reattachment scaled with the momentum flux ratio.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 1992
- Accession Number
- ADA257291
Entities
People
- David G. Bogard
- Karen Thole
- Michael E. Crawford
Organizations
- University of Texas at Austin