The challenge of stereo PIV measurements in the tip gap of a transonic compressor rotor with casing treatment

This contribution is aimed at summarizing the effort taken to apply stereoscopic PIV (SPIV) measurements in the tip clearance of a transonic compressor rotor equipped with a casing treatment. A light sheet probe was placed downstream of the stator and aligned to pass the light sheet through a stator passage into the blade tip clearance of the rotor. A setup with three cameras has been used in order to record the entire 2C velocity field and the smaller area of 3C field of view at the same time instance for comparison with earlier 2C PIV results. A homogeneous seeding distribution was achieved by means of a smoke generator. The main emphasis of the SPIV measurement was to establish a data set with high spatial resolution close to the compressor casing, where the aerodynamic effects of a CT are known to be strong. The paper will discuss some major aspects of the utilized PIV data processing and point out a variety of frequently underestimated error sources that influence the overall quality of the recovered data in spite of the fact that the individual PIV recordings seemed to be of very good quality. Thus, the authors will not focus on the PIV results and related interpretation of the flow field, but on the optimization and procedures applied during setup of the experiment and data processing, respectively.

[1]  Bernhard Wieneke,et al.  Stereo-PIV using self-calibration on particle images , 2005 .

[2]  H. D. Joslyn,et al.  A Fundamental Criterion for the Application of Rotor Casing Treatment , 1979 .

[3]  Nicolas Gourdain,et al.  Unsteady Simulation of an Axial Compressor Stage With Casing and Blade Passive Treatments , 2009 .

[4]  Ryan J. Lowe,et al.  Intensity Capping: a simple method to improve cross-correlation PIV results , 2007 .

[5]  Hong Yang,et al.  Numerical Investigation of Casing Treatment Mechanisms With a Conservative Mixed-Cell Approach , 2003 .

[6]  Wuli Chu,et al.  The Effects of Bend Skewed Groove Casing Treatment on Performance and Flow Field Near Endwall of an Axial Compressor , 2005 .

[7]  Wei Yuan,et al.  Experimental Investigation on the Effects of Unsteady Excitation Frequency of Casing Treatment on Transonic Compressor Performance , 2011 .

[8]  Jürgen Kompenhans,et al.  Particle Image Velocimetry - A Practical Guide (2nd Edition) , 2007 .

[9]  Melanie Voges,et al.  PIV Application for Investigation of the Rotor Blade Tip Interaction with a Casing Treatment in a Transonic Compressor Stage , 2008 .

[10]  T. Roesgen,et al.  Optimal subpixel interpolation in particle image velocimetry , 2003 .

[11]  Christian Willert,et al.  Adaptive PIV processing based on ensemble correlation , 2008 .

[12]  Carl D. Meinhart,et al.  Second-order accurate particle image velocimetry , 2001 .

[13]  Mark P. Wernet,et al.  Application of DPIV to study both steady state and transient turbomachinery flows , 2000 .

[14]  Christian E. Willert,et al.  Assessment of camera models for use in planar velocimetry calibration , 2006 .

[15]  Melanie Voges,et al.  INVESTIGATION OF BLADE TIP INTERACTION WITH CASING TREATMENT IN A TRANSONIC COMPRESSOR – PART 2: NUMERICAL RESULTS , 2008 .

[16]  J. Westerweel,et al.  Universal outlier detection for PIV data , 2005 .

[17]  Ajay K. Prasad,et al.  Stereoscopic particle image velocimetry , 2000 .

[18]  J. Westerweel.  Theoretical analysis of the measurement precision in particle image velocimetry , 2000 .

[19]  Nicholas J. Lawson,et al.  Three-dimensional particle image velocimetry: error analysis of stereoscopic techniques , 1997 .

[20]  Melanie Voges,et al.  Application of particle image velocimetry to a transonic centrifugal compressor , 2007 .

[21]  Michael D. Hathaway,et al.  Self-Recirculating Casing Treatment Concept for Enhanced Compressor Performance , 2002 .

[22]  Z. C. Liu,et al.  Distortion compensation for generalized stereoscopic particle image velocimetry , 1997 .

[23]  Melanie Voges,et al.  Investigation of Blade Tip Interaction With Casing Treatment in a Transonic Compressor—Part II: Numerical Results , 2011 .

[24]  Mark P. Wernet,et al.  Development of digital particle imaging velocimetry for use in turbomachinery , 2000 .

[25]  Huijing Yuan,et al.  Application of SPIV in turbomachinery , 2006 .

[26]  Markus Raffel,et al.  Particle Image Velocimetry: A Practical Guide , 2002 .

[27]  Dale E. Van Zante,et al.  Characterization of the tip clearance flow in an axial compressor using 3-D digital PIV , 2005 .

[28]  W. Sanz,et al.  Laser-optical investigation of turbine wake flow , 2003 .

[29]  Melanie Voges,et al.  Investigation of Blade Tip Interaction With Casing Treatment in a Transonic Compressor—Part I: Particle Image Velocimetry , 2011 .

[30]  Nicholas J. Lawson,et al.  Three-dimensional particle image velocimetry: experimental error analysis of a digital angular stereoscopic system , 1997 .