An experimental investigation on fluid flow characteristics in a real coolant channel of LP turbine blade with PIV technique

Abstract Using a planar particle image velocimetry (PIV) system, the fluid flow characteristics including mean velocity and pressure fields in a real coolant channel of a low pressure (LP) turbine blade have been investigated. To understand the flow characteristics within the real LP turbine blade in detail, the studied channel has a real blade-similar cross section, and the entire channel consists of two dividing walls, three passes, a 180° bend, 2 tip exits and 25 trailing edge exits. At first, the flow structures in the channel are captured by the PIV system at an inlet Reynolds number of 44,000, when all the exits are open. The experimental results exhibit different secondary flow features from the previous investigations, which were conducted mostly in simplified two-pass square or rectangular channels. Secondly, through a statistical post-processing of measured instantaneous velocity fields, the Reynolds-averaged Navier–Stokes (RANS) equations are solved to obtain the mean pressure distributions at several typical cross sections. At last, the effects of the inlet Reynolds numbers and coolant ejection from the tip exit above the 1st pass on the flow characteristics are discussed. From the comparisons of the flow characteristics obtained at different flow conditions, it can be concluded that the flow characteristics are sensible to the inlet Reynolds number and coolant ejection from tip exit.

[2]  J. Köngeter,et al.  PIV with high temporal resolution for the determination of local pressure reductions from coherent turbulence phenomena , 1999 .

[3]  Fulvio Scarano,et al.  Non-intrusive aerodynamic loads analysis of an aircraft propeller blade , 2011 .

[4]  Je-Chin Han,et al.  Recent Studies in Turbine Blade Cooling , 2004 .

[5]  Zeyuan Xu,et al.  Experimental assessment of the effects of Prandtl number and of a guide vane on the thermal development in a ribbed square-ended U-bend , 2007 .

[6]  G. Naterer,et al.  Measured turbulent entropy production with large eddy particle image velocimetry , 2007 .

[7]  Fulvio Scarano,et al.  Lagrangian and Eulerian pressure field evaluation of rod-airfoil flow from time-resolved tomographic PIV , 2011 .

[8]  S. V. Prabhu,et al.  Effect of Turn Region Treatments on the Pressure Loss Distribution in a Smooth Square Channel with Sharp 180° Bend , 2004 .

[9]  L Rathjen,et al.  Detailed Heat/Mass Transfer Distributions in a Rotating Two Pass Coolant Channel With Engine‐Near Cross Section and Smooth Walls , 2001, Annals of the New York Academy of Sciences.

[10]  A. Bölcs,et al.  PIV Investigation of the Flow Characteristics in an Internal Coolant Passage With Two Ducts Connected by a Sharp 180° Bend , 1998 .

[11]  Gongnan Xie,et al.  Gas Turbine Blade Tip Heat Transfer and Cooling: A Literature Survey , 2010 .

[12]  Joseph Katz,et al.  Instantaneous pressure and material acceleration measurements using a four-exposure PIV system , 2006 .

[13]  J. K. Sveen.  An introduction to MatPIV v. 1.6.1 , 2004 .

[14]  S. Prabhu,et al.  Pressure Drop Distribution in Smooth and Rib Roughened Square Channel with Sharp 180° Bend in the Presence of Guide Vanes , 2004 .

[15]  Jens von Wolfersdorf,et al.  The Effect of Turning Vanes on Pressure Loss and Heat Transfer of a Ribbed Rectangular Two-Pass Internal Cooling Channel , 2011 .

[16]  Heinz Herwig,et al.  Flow in Channels With Rough Walls—Old and New Concepts , 2010 .

[17]  M. Elfert,et al.  Detaild flow investigation using PIV in a typical turbine cooling geometry with ribbed walls,GT-2004-53566 , 2004 .

[18]  Fulvio Scarano,et al.  Surface pressure and aerodynamic loads determination of a transonic airfoil based on particle image velocimetry , 2009 .

[19]  Hiroshi Nakayama,et al.  Fluid Flow and Heat Transfer in Two-Pass Smooth Rectangular Channels With Different Turn Clearances , 2006 .

[20]  T. Astarita,et al.  3D reconstruction of the flow and vortical field in a rotating sharp “U” turn channel , 2010 .

[21]  S. Chang,et al.  Heat transfer and pressure drop in two-pass rib-roughened square channels with bleed from sharp bend , 2010 .

[22]  A. Bölcs,et al.  Flow Characteristics in Two-Leg Internal Coolant Passages of Gas Turbine Airfoils With Film-Cooling Hole Ejection , 2002 .

[23]  N. Fujisawa,et al.  Evaluation of pressure field and fluid forces on a circular cylinder with and without rotational oscillation using velocity data from PIV measurement , 2005 .

[24]  R. P. Vedula,et al.  Pressure drop characteristics in a rotating smooth square channel with a sharp 180° bend , 2000 .

[25]  Cameron V. King,et al.  Assessment of pressure field calculations from particle image velocimetry measurements , 2010 .

[26]  Fulvio Scarano,et al.  Evaluation of integral forces and pressure fields from planar velocimetry data for incompressible and compressible flows , 2007 .

[27]  Greg F. Naterer,et al.  Experimental uncertainty of measured entropy production with pulsed laser PIV and planar laser induced fluorescence , 2005 .

[28]  Je-Chin Han,et al.  PIV flow measurements for heat transfer characterization in two-pass square channels with smooth and 90° ribbed walls , 2002 .

[29]  Zeyuan Xu,et al.  Experimental study of thermal development in a rotating square-ended U-bend , 2009 .

[30]  Je-Chin Han,et al.  Recent Studies in Turbine Blade Internal Cooling , 2010 .

[31]  M. Elfert,et al.  PIV-Measurement of Secondary Flow in a Rotating Two-Pass Cooling System With An Improved Sequencer Technique , 2012 .

[32]  Yuichi Murai,et al.  Particle tracking velocimetry applied to estimate the pressure field around a Savonius turbine , 2007 .