The aerodynamic performance of a turbine vane was measured in a linear cascade. These measurements were conducted for exit-true chord Reynolds numbers between 150,000 and 1,800,000. The vane surface rms roughness-to-true chord ratio was approximately 2 × 10−4. Measurements were made for exit Mach numbers between 0.3 and 0.9 to achieve different loading distributions. Measurements were made at three different inlet turbulence levels. High and intermediate turbulence levels were generated using two different blown grids. The turbulence was low when no grid was present. The wide range of Reynolds numbers was chosen so that, at the lower Reynolds numbers the rough surfaces would be hydraulically smooth. The primary purpose of the tests was to provide data to verify CFD predictions of surface roughness effects on aerodynamic performance. Data comparisons are made using a two-dimensional Navier-Stokes analysis. Both two-equation and algebraic roughness turbulence models were used. A model is proposed to account for the increase in loss due to roughness as the Reynolds number increases.

Turbine vane aerodynamics were measured in a three vane linear cascade. Surface pressures and blade row losses were obtained over a range of Reynolds and Mach numbers for three levels of turbulence. Comparisons are made with predictions using a quasi-3D Navier-Stokes analysis. Turbulence intensity measurements were made upstream and downstream of the vane. The purpose of the downstream measurements was to determine how the turbulence was affected by the strong contraction through 75° of turning.

Turbine vane surface temperatures were measured in a linear cascade using an infrared non-contact thermal detector. A thermal barrier coating (TBC) was applied to the vane surface to give a rough surface. The temperature drop across the relatively thick TBC was used to determine heat transfer coefficients. Tests were conducted over a range of Reynolds and Mach numbers, resulting in large variations in hydraulic roughness. The measured heat transfer rates were significantly higher than were expected for a smooth vane. The detector was mounted in a probe holder, and traversed in a manner similar to that used for pneumatic or hot wire probes. The results showed that this approach gave useful information, and should be considered when non-contact surface temperatures are desired.