The Boundary Layer Over Turbine Blade Models with Realistic Rough Surfaces
Abstract
Surface roughness is known to have a significant impact on turbine heat loads and performance. Over time, as the turbine blades are exposed to these loads, the external surfaces become rougher, which results in increased heat loads and friction losses. The objective of the present investigation is to conduct measurements that will reveal the influence of realistic surface roughness on the near-wall behavior of the boundary layer. LDV measurements have been conducted in a Matched-Index-Of-Refraction (MIR) oil tunnel. The tunnel has been modified to operate with an accelerating freestream and an elevated freestream turbulence level in order to simulate conditions on the suction side of a high pressure turbine blade. We have made extensive boundary layer measurements over a smooth plate model and over a model with a strip of realistic rough surface. The realistic rough surface was developed by scaling actual turbine blade surface data that was provided by AFRL. The results include velocity profiles, streamwise and vertical turbulence intensity profiles, and Reynolds stress profiles. The oil tunnel arrangement has permitted velocity measurements very close to the wall (down to <1). These detailed results should be valuable to assess and guide development of computational fluid dynamics predictions.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 2004
- Accession Number
- ADA420945
Entities
People
- Ralph Budwig
Organizations
- University of Idaho