Journal of Visualization

, Volume 14, Issue 2, pp 121–127 | Cite as

Unsteady surface signature of a pulsed vortex generator jet

Regular Paper

Abstract

Porous pressure-sensitive paint (PSP) is employed as a visualization technique for unsteady flow features on a low-pressure turbine blade. Recognizing that the measurement of high-frequency pressure fluctuations in unsteady flows—especially in turbomachinery—has proven to be difficult, recent advancements in the development of porous PSP have enabled the high-resolution measurement of pressure fields with frequency content of at least 20 kHz. In this work, PSP is applied to an L1A low-pressure turbine blade section (Re = 20,000 based on axial chord) to visualize the surface dynamics of a vortex generator jet (VGJ) pulsed at 10.6 Hz with nitrogen gas. Intensity-based, time-resolved PSP measurements reveal the development and the surface structure of the VGJ as well as the spanwise variation in the blowing profile.

Graphical Abstract

Keywords

Low-pressure turbine stage Pressure-sensitive paint Unsteady flow Vortex generator jet 

List of symbols

B

Blowing ratio, B = Ujet/Uinlet, measured in quiescent conditions

Cx

Blade axial chord, 0.143 m

d

Diameter of cylindrical jet exit orifice, 2.6 mm

Ioff/Ion

Emitted light intensity ratio between wind-off and wind-on images

Rec

Reynolds number based on axial chord, UinletCx/ν

T

VGJ pulsing period (ms)

t

Instantaneous time (ms)

Uinlet

Cascade inlet velocity magnitude (m/s)

Ujet

Jet exit velocity magnitude (m/s)

Δt

Phase delay (ms)

λ

Excitation light wavelength (nm)

ν

Kinematic viscosity of air (m2/s)

References

  1. Bell JH, McLachlan BG (1996) Image registration for pressure-sensitive paint applications. Exp Fluids 22(1):78–86CrossRefGoogle Scholar
  2. Bell JH, Schairer ET, Hand LA, Mehta RD (2001) Surface pressure measurements using luminescent coatings. Annu Rev Fluid Mech 33:171–179CrossRefGoogle Scholar
  3. Bencic TJ (1998) Rotating pressure and temperature measurements on scale-model fans using luminescent paints, 34th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit, AIAA 1998–3452Google Scholar
  4. Bons JP, Sondergaard R, Rivir RB (2002) The fluid dynamics of LPT blade separation control using pulsed jets. J Turbomachinery 124(1):77–85CrossRefGoogle Scholar
  5. Bons JP, Pluim J, Gompertz K, Bloxham M, Clark JP (2008a) The application of flow control to an aft-loaded low pressure turbine cascade with unsteady wakes. ASME Turbo Expo 2008: Power for Land, Sea, and Air, GT2008–50864Google Scholar
  6. Bons JP, Reimann D, Bloxham MJ (2008b) Separated flow transition on an LP turbine blade with pulsed flow control. J Turbomachinery 130(2):021014–021022CrossRefGoogle Scholar
  7. Bourgois S, Favier J, Tensi J, Sommier E (2005) Experimental investigations on fluidic control over an airfoil. J Flow Vis Image Processing 13(3):265–286CrossRefGoogle Scholar
  8. Gregory JW (2004) Porous pressure-sensitive paint for measurement of unsteady pressures in turbomachinery, AIAA 2004–0294, 42nd AIAA Aerospace Sciences Meeting and ExhibitGoogle Scholar
  9. Gregory JW, Sullivan JP (2006) Effect of quenching kinetics on the unsteady response of pressure-sensitive paint. AIAA J 44(3):634–645CrossRefGoogle Scholar
  10. Gregory JW, Sullivan JP, Raman G, Raghu S (2007) Characterization of the microfluidic oscillator. AIAA J 45(3):568–576CrossRefGoogle Scholar
  11. Gregory JW, Asai K, Kameda M, Liu T, Sullivan JP (2008) A review of pressure-sensitive paint for high-speed and unsteady aerodynamics. Proc Inst Mec Eng, Part G: J Aerosp Eng 222(2):249–290CrossRefGoogle Scholar
  12. Lepicovsky J, Bencic TJ (2002) Use of pressure-sensitive paint for diagnostics in turbomachinery flows with shock. Exp Fluids 33(4):531–538Google Scholar
  13. Liu T, Torgerson S, Sullivan JP, Johnston R, Fleeter S (1997) Rotor blade pressure measurements in a high speed axial compressor using pressure and temperature sensitive paints. AIAA 97–0162, 35th AIAA Aerospace Sciences Meeting and ExhibitGoogle Scholar
  14. Navarra KR, Rabe DC, Fonov SD, Goss LP, Hah C (2001) The application of pressure- and temperature-sensitive paints to an advanced compressor. J Turbomachinery 123(4):823–829CrossRefGoogle Scholar

Copyright information

© The Visualization Society of Japan 2011

Authors and Affiliations

  1. 1.Department of Mechanical and Aerospace EngineeringThe Ohio State UniversityColumbusUSA

Personalised recommendations