Combined Wake and Pulsed-Jet Effects on Separation on a Turbine Airfoil

pressure-gradientregionwithmaximumjetvelocityequaltothelocalfreestreamvelocityandajetdutycycleof10%. Several different timings of the vortex generator jets with respect to the wakes were considered. In cases without vortex generator jets, the boundary layer momentarily reattached in response to the wake passing, but separated between wakes. The vortex generator jets also caused reattachment, and if the vortex-generator-jet pulsing frequency was sufficiently high, separation was largely suppressed for the full wake passing cycle. The timing of the vortex generator jets with respect to the wakes was not very important. The jet pulsing frequency needed for separation control was about the same as found previously in cases without wakes. The background freestreamturbulence effect was negligible in the presence of the larger wake and vortex-generator-jet disturbances.

[1]  Jeffrey P. Bons,et al.  Separated Flow Transition on an LP Turbine Blade With Pulsed Flow Control , 2008 .

[2]  Howard P. Hodson,et al.  Combined Effects of Surface Trips and Unsteady Wakes on the Boundary Layer Development of an Ultra-High-Lift LP Turbine Blade , 2005 .

[3]  Jeffrey P. Bons,et al.  Synchronizing Separation Flow Control With Unsteady Wakes in a Low-Pressure Turbine Cascade , 2009 .

[4]  H. Hodson,et al.  BLADEROW INTERACTIONS, TRANSITION, AND HIGH-LIFT AEROFOILS IN LOW-PRESSURE TURBINES , 2005 .

[5]  Kazutoyo Yamada,et al.  Experimental and Numerical Investigations of Wake Passing Effects upon Aerodynamic Performance of a LP Turbine Linear Cascade With Variable Solidity , 2006 .

[6]  R. Volino,et al.  Experimental and Computational Investigations of Low-Pressure Turbine Separation Control Using Vortex Generator Jets , 2009 .

[7]  Howard P. Hodson,et al.  Separation and Transition Control on an Aft-Loaded Ultra-High-Lift LP Turbine Blade at Low Reynolds Numbers: Low-Speed Investigation , 2006 .

[8]  J. Bons,et al.  Turbine Separation Control Using Pulsed Vortex Generator Jets , 2000 .

[9]  Ralph J. Volino,et al.  STRUCTURE OF OSCILLATING VORTEX GENERATOR JETS , 2005 .

[10]  Terrence W. Simon,et al.  Transition in Low-Pressure Turbines: Effects of Unsteady Acceleration and Turbulence Intensity , 2005 .

[11]  James P. Johnston,et al.  Vortex Generator Jets—Means for Flow Separation Control , 1990 .

[12]  Mounir B. Ibrahim,et al.  LES Flow Control Simulations for Highly Loaded Low Pressure Turbine Airfoil (L1A) Using Pulsed Vortex Generator Jets , 2010 .

[13]  Ralph J. Volino,et al.  Separated Flow Transition Under Simulated Low-Pressure Turbine Airfoil Conditions—Part 1: Mean Flow and Turbulence Statistics , 2002 .

[14]  R. Eldredge,et al.  Active Control of a Separating Boundary Layer with Steady Vortex Generating Jets - Detailed Flow Measurements , 2004 .

[15]  Meinhard T. Schobeiri,et al.  Effect of Turbulence Intensity and Periodic Unsteady Wake Flow Condition on Boundary Layer Development, Separation, and Reattachment Along the Suction Surface of a Low-Pressure Turbine Blade , 2007 .

[16]  R. Volino,et al.  Experimental and Computational Investigations of Separation and Transition on a Highly Loaded Low-Pressure Turbine Airfoil: Part 1 — Low Freestream Turbulence Intensity , 2008 .

[17]  Ali Mahallati,et al.  Aerodynamics of a Low-Pressure Turbine Airfoil at Low-Reynolds Numbers: Part 2 — Blade-Wake Interaction , 2007 .

[18]  Jamey Jacob,et al.  Effect of Chord Location on Separation Control with Vortex Generator Jets on Low Pressure Turbine Blades , 2004 .

[19]  Thomas Corke,et al.  Plasma Actuators for Separation Control of Low-Pressure Turbine Blades , 2006 .

[20]  Ralph J. Volino,et al.  Measurements in Separated and Transitional Boundary Layers Under Low-Pressure Turbine Airfoil Conditions , 2000 .

[21]  Ralph J. Volino.  Separation Control on Low-Pressure Turbine Airfoils Using Synthetic Vortex Generator Jets , 2003 .

[22]  Howard P. Hodson,et al.  Effects of Reynolds Number and Freestream Turbulence Intensity on the Unsteady Boundary Layer Development on an Ultra-High-Lift Low Pressure Turbine Airfoil , 2010 .

[23]  Gregory J. Walker,et al.  Investigation of the Calmed Region Behind a Turbulent Spot , 1996 .

[24]  Terrence W. Simon,et al.  Influence of Wake Passing Frequency and Elevated Turbulence Intensity on Transition. , 2005 .

[25]  Ralph J. Volino,et al.  Effect of Unsteady Wakes on Boundary Layer Separation on a Very High Lift Low Pressure Turbine Airfoil , 2010 .

[26]  Jeffrey P. Bons,et al.  Designing a High Fidelity Wake Simulator for Research Using Linear Cascades , 2009 .

[27]  Meinhard T. Schobeiri,et al.  Effect of reynolds number and periodic unsteady wake flow condition on boundary layer development, separation, and intermittency behavior along the suction surface of a low pressure turbine blade , 2007 .

[28]  Mounir B. Ibrahim,et al.  Separation control on high lift low-pressure turbine airfoils using pulsed vortex generator jets , 2012 .

[29]  Mounir B. Ibrahim,et al.  Separation Control on a Very High Lift Low Pressure Turbine Airfoil Using Pulsed Vortex Generator Jets , 2011 .

[30]  Jeffrey P. Bons,et al.  Combined Unsteady Wakes and Active Flow Control on a Low-Pressure Turbine Airfoil , 2011 .

[31]  J. Wills.  The correction of hot-wire readings for proximity to a solid boundary , 1962 .

[32]  Ralph J. Volino.  Passive Flow Control on Low-Pressure Turbine Airfoils , 2003 .

[33]  Howard P. Hodson,et al.  Prediction of the Becalmed Region for LP Turbine Profile Design , 1998 .

[34]  Ali Mahallati,et al.  Aerodynamics of a low-pressure turbine airfoil at low reynolds numbers-part ii: Blade-wake interaction , 2013 .

[35]  Mounir B. Ibrahim,et al.  LES and URANS Computational Investigations of LPT Blade (L1A) Separation Control using Vortex Generator Jets , 2009 .

[36]  John P. Clark,et al.  The Application of Flow Control to an Aft-Loaded Low Pressure Turbine Cascade With Unsteady Wakes , 2012 .

[37]  R. E. Mayle,et al.  The 1991 IGTI Scholar Lecture: The Role of Laminar-Turbulent Transition in Gas Turbine Engines , 1991 .

[38]  J. Bons,et al.  The Fluid Dynamics of LPT Blade Separation Control Using Pulsed Jets , 2001 .

[39]  John P. Clark,et al.  Predicting Transition in Turbomachinery—Part I: A Review and New Model Development , 2007 .

[40]  Ralph J. Volino,et al.  Experiments With Three-Dimensional Passive Flow Control Devices on Low-Pressure Turbine Airfoils , 2005 .

[41]  R. Volino.  Separated Flow Measurements on a Highly Loaded Low-Pressure Turbine Airfoil , 2008 .