Film Cooling Effectiveness Distributions on a Turbine Blade Cascade Platform With Stator-Rotor Purge and Discrete Film Hole Flows

An experimental investigation to obtain detailed film cooling effectiveness distributions on a cooled turbine blade platform within a linear cascade has been completed. The Reynolds number of the freestream flow is 3.1 × 10 5 , and the platform has a labyrinthlike seal upstream of the blades to model a realistic stator-rotor seal configuration. An additional coolant is supplied to the downstream half of the platform via discrete film cooling holes. The coolant flow rate through the upstream seal varies from 0.5% to 2.0% of the mainstream flow, while the blowing ratio of the coolant through the discrete holes varies from 0.5 to 2.0 (based on the mainstream velocity at the exit of the cascade). Detailed film cooling effectiveness distributions are obtained using the pressure sensitive paint (PSP) technique under a wide range of coolant flow conditions and various freestream turbulence levels (0.75% or 13.4%). The PSP technique clearly shows how adversely the coolant is affected by the passage induced flow. With only purge flow from the upstream seal, the coolant flow rate must exceed 1.5% of the mainstream flow in order to adequately cover the entire passage. However, if discrete film holes are used on the downstream half of the passage, the platform can be protected while using less coolant (i.e., the seal flow rate can be reduced).

[1]  T. Schulenberg,et al.  Prediction and Measurement of Film Cooling Effectiveness for a First-Stage Turbine Vane Shroud , 1990 .

[2]  H. Hodson,et al.  Heat Transfer Committee Best Paper of 1995 Award: Distribution of Film-Cooling Effectiveness on a Turbine Endwall Measured Using the Ammonia and Diazo Technique , 1996 .

[3]  Howard P. Hodson,et al.  The Design of an Improved Endwall Film-Cooling Configuration , 1999 .

[4]  Je-Chin Han,et al.  Film Cooling Effectiveness on the Leading Edge of a Rotating Turbine Blade , 2004 .

[5]  Terrence W. Simon,et al.  Turbine Endwall Aerodynamics and Heat Transfer , 2006 .

[6]  Je-Chin Han,et al.  Assessment of Steady State PSP and Transient Ir Measurement Techniques for Leading Edge Film Cooling , 2005 .

[7]  L. Langston,et al.  Secondary Flows in Axial Turbines—A Review , 2001, Annals of the New York Academy of Sciences.

[8]  R. Goldstein,et al.  Turbulent Transport on the Endwall in the Region Between Adjacent Turbine Blades , 1987 .

[9]  Howard P. Hodson,et al.  AERODYNAMIC ASPECTS OF ENDWALL FILM-COOLING , 1997 .

[10]  Terrence W. Simon,et al.  Measurements Over a Film-Cooled, Contoured Endwall With Various Coolant Injection Rates , 2001 .

[11]  A. E. Forest,et al.  Endwall heat transfer and film cooling measurements in a turbine cascade with injection upstream of leading edge , 2004 .

[12]  Je-Chin Han,et al.  Assessment of Steady State PSP, TSP, and IR Measurement Techniques for Flat Plate Film Cooling , 2005 .

[13]  L. Langston,et al.  Three-Dimensional Flow Within a Turbine Cascade Passage , 1977 .

[14]  Je-Chin Han,et al.  Film Cooling Effectiveness Distribution on a Gas Turbine Blade Platform With Inclined Slot Leakage and Discrete Film Hole Flows , 2008 .

[15]  Je-Chin Han,et al.  Influence of Mainstream Turbulence on Heat Transfer Coefficients From a Gas Turbine Blade , 1994 .

[16]  L. S. Langston,et al.  Crossflows in a Turbine Cascade Passage , 1980 .

[17]  Je-Chin Han,et al.  Film-Cooling Effectiveness on a Gas Turbine Blade Tip Using Pressure-Sensitive Paint , 2005 .

[18]  Terrence W. Simon,et al.  Effects of Slot Bleed Injection Over a Contoured Endwall on Nozzle Guide Vane Cooling Performance: Part I — Flow Field Measurements , 2000 .

[19]  Luzeng Zhang,et al.  Turbine Nozzle Endwall Inlet Film Cooling: The Effect of a Back-Facing Step , 2003 .

[20]  Je-Chin Han,et al.  Film Cooling Effectiveness on the Leading Edge of a Rotating Film-Cooled Blade Using Pressure Sensitive Paint , 2005 .

[21]  G. Barigozzi,et al.  Fan-Shaped Hole Effects on the Aero-Thermal Performance of a Film-Cooled Endwall , 2006 .

[22]  Karen A. Thole,et al.  Effects of Mid-Passage Gap, Endwall Misalignment and Roughness on Endwall Film-Cooling , 2005 .

[23]  E. R. G. Eckert,et al.  Film Cooling of the Gas Turbine Endwall by Discrete-Hole Injection , 1996 .

[24]  S. P. Harasgama,et al.  Film Cooling Research on the Endwall of a Turbine Nozzle Guide Vane in a Short Duration Annular Cascade: Part 1—Experimental Technique and Results , 1992 .

[25]  Hugh W. Coleman,et al.  Experimentation and Uncertainty Analysis for Engineers , 1989 .

[26]  MINKING K. CHYU.  Heat Transfer near Turbine Nozzle Endwall , 2001, Annals of the New York Academy of Sciences.

[27]  R. P. Roy,et al.  Flow and Heat Transfer at the Hub Endwall of Inlet Vane Passages — Experiments and Simulations , 2000 .

[28]  Sunao Aoki,et al.  An Experimental Study of Heat Transfer and Film Cooling on Low Aspect Ratio Turbine Nozzles , 1990 .

[29]  Richard J Goldstein,et al.  Flow visualization in a linear turbine cascade of high performance turbine blades , 1995 .

[30]  Martin Nicklas,et al.  Film-Cooled Turbine Endwall in a Transonic Flow Field: Part II—Heat Transfer and Film-Cooling Effectiveness , 2001 .

[31]  M. F. Blair,et al.  An Experimental Study of Heat Transfer and Film Cooling on Large-Scale Turbine Endwalls , 1974 .

[32]  Karen A. Thole,et al.  Adiabatic Effectiveness Measurements of Endwall Film-Cooling for a First-Stage Vane , 2005 .

[33]  Terrence W. Simon,et al.  Film Cooling Experiments With Flow Introduced Upstream of a First Stage Nozzle Guide Vane Through Slots of Various Geometries , 2002 .

[34]  Je-Chin Han,et al.  Film-Cooling Effectiveness on Squealer Rim Walls and Squealer Cavity Floor of a Gas Turbine Blade Tip Using Pressure Sensitive Paint , 2005 .

[35]  Luzeng J. Zhang,et al.  Turbine Nozzle Endwall Film Cooling Study Using Pressure-Sensitive Paint , 2001 .