School of Aerospace Engineering MITE A Ph.D. Proposal Saeid Niazi Advisor:Lakshmi N. Sankar School of Aerospace Engineering Georgia Institute of Technology Supported by the U.S. Army Research Office Under the Multidisciplinary University Research Initiative (MURI) on Intelligent Turbine Engines Numerical Monitoring of Numerical Monitoring of Rotating Stall and Rotating Stall and Separation Control in Axial Separation Control in Axial Compressors Compressors
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A Ph.D. Proposal Saeid Niazi Advisor:Lakshmi N. Sankar School of Aerospace Engineering
Numerical Monitoring of Rotating Stall and Separation Control in Axial Compressors. A Ph.D. Proposal Saeid Niazi Advisor:Lakshmi N. Sankar School of Aerospace Engineering Georgia Institute of Technology - PowerPoint PPT Presentation
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School of Aerospace Engineering
MITE
A Ph.D. Proposal Saeid Niazi
Advisor:Lakshmi N. Sankar
School of Aerospace EngineeringGeorgia Institute of Technology
Supported by the U.S. Army Research Office Under the Multidisciplinary University Research Initiative (MURI) on Intelligent Turbine Engines
Numerical Monitoring of Rotating Numerical Monitoring of Rotating Stall and Separation Control in Axial Stall and Separation Control in Axial
CompressorsCompressors
School of Aerospace Engineering
MITE
OverviewOverview Objectives and Motivation Surge and Rotating Stall Mathematical and Numerical Formulation NASA Axial Rotor 67 Results
Literature Survey of NASA Rotor 67Literature Survey of NASA Rotor 67• Computation of the stable part of the design speed operating
line: • NASA Glenn Research Center (Chima, Wood, Adamczyk, Reid, and Hah)• MIT (Greitzer, and Tan)• U.S. Army Propulsion Laboratory (Pierzga) • Alison Gas Turbine Division (Crook)• University of Florence, Italy (Arnone )• Honda R&D Co., Japan (Arima)
• Effects of tip clearance gap: • NASA Glenn Research Center (Chima and Adamczyk)
• MIT (Greitzer)
• Shock boundary layer interaction and wake development: • NASA Glenn Research Center (Hah and Reid).
• End-wall and casing treatment: • NASA Glenn Research Center (Adamczyk)
0.00 0.36 0.73 1.09 1.45 1.82 2.18 Time (Rotor Revolution)
Pre
ssur
e
Onset of the Stall (Disturbed Inlet)Onset of the Stall (Disturbed Inlet)
•Inlet distortion simulated by dropping the stagnation pressure in one block by 20%
•Flow is no longer symmetric from blade to blade.
•Frequency of rotating stall is N, where : blade passing frequency
School of Aerospace Engineering
MITE
Bleed Valve ControlBleed Valve Control
Bleed Area
Hub
Shroud
• Pressure, density and tangential velocities are extrapolated from interior. .• Un = mb/(Ab)
School of Aerospace Engineering
MITE
Bleed Valve ControlBleed Valve Control3% Bleeding nearly eliminates reversed flow near LE
School of Aerospace Engineering
MITE
Bleed Valve ControlBleed Valve Control
-50
-30
-10
10
30
50
-40 -20 0 20 40
-50
-30
-10
10
30
50
-40 -20 0 20 40
% Mass Flow Rate Fluctuations
% Total Pressure
Fluctuations
Without Control
With Bleed Valve
3% bleed air reduces the total pressure fluctuations by 75%
School of Aerospace Engineering
MITE
Bleed Valve ControlBleed Valve ControlAxial Velocity Near LEAxial Velocity Near LE
% F
rom
Hub
After 1.5 Rev.
After 0.5 Rev.
Bleed Valve.
School of Aerospace Engineering
MITE
ConclusionsConclusions•The CFD compressor modeling was applied to the NASA Rotor 67 axial compressor.
•The calculated shock strength and location at the peak efficiency are in good agreement with experimental results.
•For the axial compressor, tip leakage vortex is stronger under off-design conditions compared to peak efficiency conditions.
School of Aerospace Engineering
MITE
•Results revealed that instabilities during the onset of stall in NASA Rotor67 is of mild surge type. The mild surge was followed by a modified surge. (Surge and rotating stall interaction)
•When flow in the inlet at the onset of the stall was disturbed, flow-field became asymmetric and rotating stall was triggered.
•Stall and surge can be eliminated by the use of small amounts of bleeding from the diffuser.
Conclusions (Continued…)Conclusions (Continued…)
School of Aerospace Engineering
MITE
Proposed WorkProposed Work
• Should recent Rotor 37 rotating stall data become publicly available (Contact: Dr. Michelle Bright, NASA Glenn), rotating stall control of Rotor 37 will be attempted.
• Two additional types of bleed control will be studied.Bleed