DISCHARGE COEFFICIENT OF TURBINE COOLING HOLES - A REVIEW

Published information on the discharge coefficient of film cooling hol es is classified in terms of the hole geometry, the external flow cond itions at inlet and outlet, and the method of evaluation. This may be either theoretical or experimental. The information is reviewed primar ily in the context of its use for evaluating discharge coefficients fo r conditions not directly covered by published data. It is shown that potential flow analyses can give acceptable accuracy for simple geomet ries with crossflows, while more complex cases require the use of corr elated data, which may be incorporated in a range of predictive scheme s. Deficiencies and inconsistencies in the published information are h ighlighted, and future developments are discussed.