Abo Bibliothek: Guest

ISSN Online: 2377-424X

ISBN Print: 1-56032-797-9

International Heat Transfer Conference 11
August, 23-28, 1998, Kyongju, Korea

EFFECTS OF HOLE GEOMETRY ON HEAT (MASS) TRANSFER AND FILM COOLING EFFECTIVENESS

Get access (open in a dialog) DOI: 10.1615/IHTC11.1210
pages 499-504

Abstrakt

The present study investigates local heat transfer characteristics around a film cooling jet entering a cross flow with compound angle orientations. Two types of film cooling hole geometry are employed: cylindrical hole with constant cross section and shaped hole with conically enlarged exit. The film cooling jet is injected through a single hole, which is inclined at 30 ° to the surface and rotatable in lateral direction from 0 ° to 90 °, for the blowing rates (mass flux ratios) of 0.5, 1.0 and 2.0. The naphthalene sublimation technique has been employed to determine both local heat (mass) transfer coefficients and local adiabatic wall (impermeable wall) film cooling effectiveness near the injection hole. The two parameters are obtained from separate tests using pure air and naphthalene saturated air injections. The results indicate that the injected jet through the straight hole protects the surface effectively at low blowing rates and spreads more widely with the compound angle injections than the axial injection. Using the shaped hole, higher and more uniform effectiveness values are obtained even for relatively high blowing rates.