Compressor Cascade Pressure Rise Prediction
ME 491 ProjectDepartment of Mechanical Engineering, IUPUIJulia Zafian-ShortDecember 2004
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Outline
• Goals and Approach
• Computational Setup
• Results
• Summary and Conclusions
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Goals and Approach
• To model flow around a NASA/GE E3 rotor blade.
• Apply 2-D CFD using Star-design.
• Quantitative post processing using starviz.
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Computational Setup• Domain and boundary conditions
• Mesh
– Parameters
– Cell type and sizes (near wall and far field)
• Solution parameters
– Method
– Convergence criteria
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Domain, Boundary Conditions and Mesh
Inlet, velocity
60 m/s
30 m/sPeriodic
Periodic
SymmetryNo change Normal to Surface
Pressure
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MeshTetrahedral Cells
Prismatic Cells
7 layersSurface size 0.1
Subsurface Thickness 0.5
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Method
• Incompressible flow assumptions
• Upwind differencing
• High Reynolds number K-epsilon
• Convergence on 0.001Mass Flow Residual
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Results
• Velocity
• Pressure
• Pressure rise characteristic
• Flow features
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Tangential Velocity, Vy -70 to –20 m/s, increment of 5 m/s
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Axial Velocity, Vz15 to 45 m/s, increment of 3 m/s
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Pressure97,900 to 100,400 Pa, increment 250Pa
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Stagnation Pressure100,400-101,600 Pa, increment 120 Pa
Wake
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Stagnation Pressure Coefficient-0.4 to 0, increment of 0.04
Dimensionless Stagnation Pressure(using reference values from the inlet)
Cp=(P-Pref)/(0.5rVref2)
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Similar Calculations for a Range of Inlet Axial Velocities.
Pressure Coefficient Vs. Axial Velocity
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0 10 20 30 40
Axial Velocity
Pre
ss
ure
Co
eff
icie
nt
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Streamline Comparison for Different Inlet Velocities
Inlet Velocity
60 m/s
30 m/s
Inlet Velocity
SeparationBubble
60 m/s
16 m/s
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Summary and Conclusions
• The operating limit for the incoming axial velocity is found to be 20 m/s for maximum pressure gradient.
• As the mass flow drops further, the angle between the flow and the leading edge of the blade increases, increasing the wake.
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