Film Effectiveness Correlations for Cylindrical and Fan-Shaped Holes, Introducing Local Pressure Coefficient
2012 (English)In: ASME Turbo Expo 2012: Turbine Technical Conference and Exposition, Volume 4: Heat Transfer, Parts A and B, Copenhagen, Denmark, June 11–15, 2012, ASME Press, 2012, Vol. 4, 1491-1500 p.Conference paper (Refereed)
Most of the proposed correlations for prediction of gas turbinefilm cooling performance in the open literature rely on experimentsconducted on flat plates. These correlations neglectadverse pressure gradient effects present in the flow field for airfoillike configurations. The continuous change in flow characteristicsin the main flow field from leading edge to trailingedge that will affect the film cooling performance is also neglected.In this study correlations are derived from measurementsconducted on a gas turbine vane working at engine likeconditions. This will take into account the effect of hole positionand the local flow situation. Indeed, cooling holes locatedat three (five) different positions with blowing ratio ranges from0.3-2.5 (0.9-6) have been considered along the suction (pressure)sides. The non-dimensional pressure coefficient CP, at the exitlocation of each hole has been introduced as a new variable toderive a single correlation for either suction or pressure sides.Three main variables: downstream distance, blowing ratio, andlocal CP together with the two way interaction between thesevariables are introduced into a commercial statistical analysisprogram, Minitab. Stepwise regression analysis has been performedto highlight factors with greatest influence on the correlationmodel. Appropriateness of the derived model is measuredbased on the adjusted coefficient of determination, R2ad j. Correlationsare derived for eight different configurations: for suctionand pressure sides, cylindrical and fan-shaped holes and in thepresence and absence of showerhead cooling. Despite the complexity of the flow due to high blowing ratio (existence of lift off)and also variation of film cooling performance from one positionto another, the calculated R2adj values indicate a high predictabilityof the proposed correlation model. The suggested correlationmodel can be useful for optimizing the location of one or severalrows of cooling holes around the vane and also one single rowperformance.
Place, publisher, year, edition, pages
ASME Press, 2012. Vol. 4, 1491-1500 p.
Film Cooling, Gas Turbine, Film effectiveness, Correlation, Fan-shaped Holes, Cylindrical Holes
Fluid Mechanics and Acoustics
IdentifiersURN: urn:nbn:se:liu:diva-116987DOI: 10.1115/GT2012-69021ISBN: 978-0-7918-4470-0OAI: oai:DiVA.org:liu-116987DiVA: diva2:801880
ASME Turbo Expo 2012, June 11–15, Copenhagen, Denmark
ProjectsTurbo Power Program