An Experimental Study of Heat Transfer in a Large-Scale Turbine Rotor Passage

Abstract

An experimental study of the heat transfer distribution in a turbine rotor passage was conducted in a large–scale, ambient temperature, rotating turbine model. Meat transfer was measured for both the full–span suction and pressure surfaces of the airfoil as well as for the hub endwall surface. The objective of this program was to document the effects of flow three–dimensionality on the heat transfer in a rotating blade row (vs. a stationary cascade). Of particular interest were the effects of the hub and tip secondary flows, tip leakage and the leading–edge horseshoe vortexsystem. The effect of surface roughness on the passage heat transfer was also investigated. Midspan results are compared with both smooth–wall and rough–wall finite–difference two dimensional heat transfer predictions. Contour maps of Stanton number for both the rotor airfoil and endwall surfaces revealed numerous regions of high heat transfer produced by the three dimensional flows within the rotor passage. Of particular importance are regions of local enhancement (as much as 100% over midspan values) produced on the airfoil suction surface by the secondary flows and tip–leakage vortices and on the hub endwall by the leading–edge horseshoe vortex system.

Effects of Rotation on Blade Surface Heat Transfer: An Experimental Investigation

“…This facility with its relatively long run-time is capable of taking highly accurate heat transfer measurements on the rotor. Blair (1994) used a low-speed 11/2 stage rotating facility to measure the time-mean heat transfer around a rotor blade and investigate the influence of surface roughness, incidence and Reynolds number.…”

Prediction of Surface Roughness and Incidence Effects on Turbine Performance

“…Table N shows that just reducing Af and maintaining K at 0.0 does not sufficiently decrease efficiency to account for the measured efficiency change due to surface roughness. Also, Blair(1992) decreased the near wall damping for his prediction of the effect of surface roughness on turbine blade heat transfer. However, when the turbulence model that was used in the present work was used to predict the heat transfer for the rough blade tests of Dunn et al(1992), good agreement was achieved using an A+ of 26.…”

Purge flow effects on rotor hub endwall heat transfer with extended endwall contouring into the disk cavity

“…Time resolved data was presented (among others) by (Dunn et al, 1984) and (Abhari et al, 1992) using thin film heat flux gauges. Endwall heat transfer measurements in a rotating facility were first presented by (Blair, 1992). Recently, (Lazzi Gazzini et al, 2017b) presented high-resolution heat transfer measurements using high-speed infrared thermography on the rotor endwall, taken in the same facility as used for this study.…”