Correlation of Film-Cooling Effectiveness From Thermographic Measurements at Enginelike Conditions

Adiabatic film-cooling effectiveness on a flat plate surface downstream of a row of cylindrical holes is investigated. Highly resolved two-dimensional surface data were measured by means of infrared thermography and carefully corrected for local conduction and radiation effects. These locally acquired data are laterally averaged to give the streamwise distributions of the effectiveness. An independent variation of the flow parameters blowing rate, density ratio, and turbulence intensity as well as the geometrical parameters streamwise ejection angle and hole spacing is examined. The influences of these parameters on the lateral effectiveness is discussed and interpreted with the help of surface distributions of effectiveness and heat transfer coefficients presented in earlier publications. Besides the known jet in cross-flow behavior of coolant ejected from discrete holes, these data demonstrate the effect of adjacent jet interaction and its impact on jet lift-off and adiabatic effectiveness. In utilizing this large matrix of measurements the effect of single parameters and their interactions are correlated. The important scaling parameters of the effectiveness are shaped out during the correlation process and are discussed. The resulting new correlation is designed to yield the quantitatively correct effectiveness as a result of the interplay of the jet in crossflow behavior and the adjacent jet interaction. It is built modularly to allow for future inclusion of additional parameters. The new correlation is valid without any exception within the full region of interest, reaching from the point of the ejection to far downstream, for all combinations of flow and geometry parameters.

[1]  Achmed Schulz,et al.  High Resolution Measurements of Local Effectiveness by Discrete Hole Film Cooling , 1999 .

[2]  Achmed Schulz,et al.  An Overall Correlation of Film Cooling Effectiveness From One Row of Holes , 1997 .

[3]  A. Bölcs,et al.  Utilization of the Transient Liquid Crystal Technique for Film Cooling Effectiveness and Heat Transfer Investigations on a Flat Plate and a Turbine Airfoil , 1997 .

[4]  Richard J Goldstein,et al.  Film Cooling With Large Density Differences Between the Mainstream and the Secondary Fluid Measured by the Heat-Mass Transfer Analogy , 1977 .

[5]  G. J. Sturgess.  FILM COOLING OPTIMIZATION FOR MINIMUM COOLING AIRFLOW IN AIRCRAFT GAS-TURBINES , 1968 .

[6]  C.J.P. Forth,et al.  SCALING PARAMETERS IN FILM-COOLING , 1986 .

[7]  David G. Bogard,et al.  Adiabatic Effectiveness, Thermal Fields, and Velocity Fields for Film Cooling With Large Angle Injection , 1995 .

[8]  D. Lampard,et al.  The Flow and Film Cooling Effectiveness Following Injection through a Row of Holes , 1980 .

[9]  Achmed Schulz,et al.  High-Resolution Measurements of Local Heat Transfer Coefficients From Discrete Hole Film Cooling , 2001 .

[10]  D. Metzger,et al.  Evaluation of heat transfer for film-cooled turbine components , 1971 .

[11]  J. H. Whitelaw,et al.  The prediction of wall temperature in the presence of film cooling , 1971 .

[12]  Achmed Schulz,et al.  Heat Flux Reduction From Film Cooling and Correlation of Heat Transfer Coefficients From Thermographic Measurements at Enginelike Conditions , 2002 .

[13]  David G. Bogard,et al.  Effects of Free-Stream Turbulence and Surface Roughness on Film Cooling , 1996 .

[14]  Achmed Schulz,et al.  In Situ Calibration for Quantitative Infrared Thermography , 1996 .

[15]  G. N. Abramovich.  The Theory of Turbulent Jets , 2003 .

[16]  D. Mukherjee.  Film Cooling With Injection Through Slots , 1976 .

[17]  Achmed Schulz,et al.  High Resolution Measurements of Local Heat Transfer Coefficients by Discrete Hole Film Cooling , 1999 .

[18]  Michael Scheurlen,et al.  CFD based sensitivity study of flow parameters for engine like film cooling conditions , 1996 .

[19]  R. J. Goldstein,et al.  ADIABATIC WALL TEMPERATURE AND HEAT TRANSFER DOWNSTREAM OF INJECTION THROUGH TWO ROWS OF HOLES. , 1977 .

[20]  Achmed Schulz,et al.  High-Resolution Measurements of Local Effectiveness From Discrete Hole Film Cooling , 2001 .

[21]  Richard B. Rivir,et al.  The Effect of High Freestream Turbulence on Film Cooling Effectiveness , 1994 .