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.