Effect of Rotation on Jet Impingement Heat Transfer for Various Jet Configurations

The present study uses a novel transient liquid crystal technique to measure heat transfer on a rotating, radially outward coolant channel with jet impingement and a crossflow outlet condition. The jet impingement cooling scheme is studied on the leading and trailing sides of a gas turbine internal coolant channel with the jet impingement target surface oriented normal to the direction of rotation. Several aspects of jet impingement are studied under rotating conditions: effect of increasing Rotation number (Ro = 0–0.003), effect of jet inclination angle (90° and 70° from the vertical), and effect of jet-to-target surface distance (H/d = 1, 3, and 5). Heat transfer measurements are obtained on the target surface using the transient liquid crystal technique. All configurations studied have a constant jet-to-jet spacing, P/d = 5. The spacing between the two adjacent rows is P/d = 3. Corresponding flow measurements are taken from stationary conditions. Results show that rotation does not change the heat transfer magnitudes and distributions greatly compared to the stationary results for all H/d and jet orientation cases. As x/d increases, stationary H/d = 5 heat transfer results show a steady decrease, where effectiveness of the jets diminishes. As x/d increases for H/d = 3, the maximum and minimum heat transfer values dampen to a steady constant average value. As x/d increases for H/d = 1, the heat transfer begins very low then steadily increases for higher x/d.