The Effects of the Thermal Boundary Condition and Turbulence on Heat Transfer from a Cylinder, Flat Plate, and Turbine Blade Using the Transient Shroud and Heated-Coating Techniques.
Abstract
A new technique to measure local heat transfer is developed, it and other methods are used to study the effects of the thermal boundary condition on local heat transfer and turbulence level effects on turbine blade heat transfer. The new technique is called the shroud technique and is a variation on the transient method. It is designed for use on arbitrarily shaped models in a wind tunnel. The shroud acts as a protective covering during in-situ heating of the model. A transient is produced by sudden removal of the shroud. Measurements on a cylinder in cross-flow are used as one method for validation of this technique. These measurements showed that the shroud technique produced good results except in the wake region where the duration of the flow development sometimes created problems. The shroud technique and a gold-film heated-coating method are both used for measurements on a flat plate with a laminar boundary layer to investigate the effect of thermal boundary conditions. The results are compared to numerical solutions, done as part of this study, for uniform temperature, uniform heat flux, and transient thermal boundary conditions. The experimental results agreed well with theory with the uniform heat flux producing 36% higher heat transfer rates than those for uniform temperature. The transient results were highly dependent on the non-dimensional temperature used, producing heat transfer rates as low as the uniform temperature or higher than the uniform heat flux boundary conditions.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1995
- Accession Number
- ADA292646
Entities
People
- Robert J. Butler
Organizations
- Air Force Institute of Technology