Integrated Flow Control Devices for the Design of Enhanced Low Pressure Turbines
Final rept. 3 Jan 2003-2 Jan 2004
BRIGHAM YOUNG UNIV PROVO UT DEPT OF MECHANICAL ENGINEERING
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Flow separation limits the efficiency of low-pressure turbines LPTs in aircraft engines. Recent experiments with vortex generator jets VGJs, conducted in AFRLs low-speed cascade at Wright-Patterson AFB, have demonstrated dramatic reductions in separation losses. The critical science that wilt enable this design innovation to reach its potential is a comprehensive understanding of the effect of VGJs on a separating boundary layer. Experiments are underway at BYU to better understand the basic physics of the separation control phenomenon and establish the quantitative links between the underlying flow physics and LPT performance. Two-component velocity measurements of VGJ evolution have been made along a flat wall with no freestream pressure gradient and at pressure gradient conditions typical of a low pressure turbine suction surface. Initial measurements are also being taken in a linear cascade for comparison with the flat wall studies. Data clearly show the presence of streamwise vortices which provide the necessary boundary layer mixing to inhibit separation. Vortex development is modified when jet injection occurs in an adverse pressure gradient. The effects of freestream turbulence will also be considered. These detailed flow measurements are suitable for code validation.
- Jet and Gas Turbine Engines