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 degrees and 70 degrees 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 Hid 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.