Bladeless Compression System - ICOPE presentation Part 2

Theoretical treatment Part 2

1. A Bladeless Turbocompressor Concept:
Shear Driven Gas Compression with Deformable Structures –
Part 2: Operating Principles and Theory
ASME 2017 Power & Energy Conference
June 26-30, 2017, Charlotte, North Carolina
Hooshang Heshmat, PhD
José Luis Córdova, PhD
www.mohawkInnovative.com

2. Introduction
NovelApproachtoBladelessCompressorDesign
•Operating principle: balance between viscous and pressure
forces
•Establish shear flow between driven rotating disk and
compliant surface counterface
•Convert shaft power into hydrodynamic pressure
•Similar to self-pressurized compliant foil Thrust bearings and
Axial seals which operate in the Elasto-hydrodynamic regime

3. Evolution from Bladed to Bladeless
Compression in traditional turbo-
compressors is a balance between
inertial and pressure forces
•Rotating blades impart
momentum to the flow.
•As the flow reaches the diffuser,
momentum is converted into
pressure

4. What
Happens
if You
Remove
Blades?

5. Baseline
Blade
Height

7. 50%
Reduction

10. 90%
Reduction

11. Bladeless

12. 100% Bladeless

13. Modeling For Effect of Blade Height Reduction
Baseline
Bladeless

14. Limit of Conventional Compressor Analysis for
Blade Height Reduction to Smooth Disc
Baseline Height
½ x Baseline
1/4x Baseline
1/10x Baseline
2x Baseline Height

15. Schematic of Bladeless Turbocompressor Concept

16. Proof of Concept, Prototype Experimental Performance

17. Elasto-Hydrodynamic Model
Coupled Flow/Structure Interaction
•Flow viscous/pressure force balance modeled via
Reynolds equation
•Valid if nominal gap to characteristic length ratio is small,
i.e., h
0/R
o≈0.001,
•Inertial effects in Navier-Stokes equations are negligible
since they are order (h
0/R
o)
2
and need only be considered
for large values of the modified Reynolds number Re
z.
•At the rotational speeds and characteristic dimensions
relevant to bladeless air compression,
Re
z<1500 i.e., Laminar Flow
•Compliant Bump/Smooth Foil interactions modeled
via thin-plate theory with Frictional interactions

18. Model Equations for Pressure and Fluid Film Gap, h
Highly non-linear system must be solved
numerically

19. Smooth Elastic Top Foil Deflection Using FDA & FEA (Visually Enhanced)
19

20. Proof of Concept: Operating Conditions
Model is solved to simulate
experimental system conditions:
•Effective disk size:
•R
i= 7.6 mm, R
o= 14.1 mm
•Four sector compliant counterface,
•Disk operating speed:
•(50,000 to 360,000 rpm)
•Nominal initial gap:
•0.03 mm < h
0< 0.635 mm
Solution for EH-pressure over a single
compliant foil pad

21. Calculated Velocity Vector Field

22. Calculated Flow Velocity and Volumetric Flow

23. Parametric Study Results –P vs. Gap & Speed
0.00001
0.0001
0.001
0.01
0.1
1
10
100
0 50 100 150 200 250 300 350 400
Maximum Pressure [kPa]
Rotating Speed [kRPM]
Maximum Pressure vs. Rotating Speed for Varying Gap
0.03 mm 0.05 mm 0.07 mm 0.1 mm 0.2 mm 0.61 mm
0.03 mm
0.61 mm
{h
0/R
o≈ 0.044 >>> 0.001}

24. Parametric Study Results –Flow vs. Gap & Speed
1
10
100
0 50 100 150 200 250 300 350 400
Flow
[L/min]
Rotating Speed [kRPM]
Flow vs. Rotating Speed for Varying Gap
0.03 mm 0.05 mm 0.07 mm 0.1 mm 0.2 mm 0.61 mm
0.03 mm
0.61 mm

25. Required Power as a function of Speed and Gap
0
10
20
30
40
50
60
0 50 100 150 200 250 300 350 400
Power [W]
Rotating Speed [kRPM]
Power vs. Rotating Speed for Varying Gap
0.03 mm 0.05 mm 0.07 mm 0.1 mm 0.2 mm 0.61 mm
0.03 mm
0.61 mm
0.05 mm

26. Performance Map, Bladeless Compressor Concept
0.1
1
10
100
0 20 40 60 80
Pressure [kPa]
Flow [L/min]
Experimental Data Overlaid on Theoretical Performance Map
T7R1-S1-Tip
T8R2-S2-CDP
Experiment Stage 1
Experiment Stage 2

27. Compression Efficiency --Theory vs Experiment

28. Pressure and Flow approximation via Centrifugal Model

29. Comparison of Models: EHD vs Centrifugal
Centrifugal Model
EH Model
Gap: 0.2 mm
0.635 mm

30. Comparison of Theoretical Models, EHD vs Centrifugal
Centrifugal Model
EH Model
.2 mm
.635 mm
.635 mm
.2 mm

31. Bladeless Technology
•Unconventional theoretical methodology was explored and applied.
•Good agreements between theory and experiment were achieved.
•Design optimization based on developed numerical technique is
underway.
Performance
•Bladeless compression concept appears to be impervious to
surge/choke phenomena during off-design operation.
•Speed/Size limitations are directly related to the ultimate yield
strength of disk materials.
•Counterintuitively, this novel concept proved to be highly efficient
system for a wide range of operating parameters.

32. Concluding Remarks
It doesn’t matter how beautiful our theoretical treatment is,
It doesn’t matter how innovative our novel concept is,
If the experimental concept doesn’t work and/or theory doesn’t
agree with the experiment, …
One may conclude simply that, “both are wrong!”
Yet the scientific views end in awe and mystery, lost at the edge
in UNCERTAINTY.
We have presented here today a novel and practical concept,
backed by EHD theoretical model that shall pave the road for
opening many windows of opportunity and products.

33. Conceptual Multi-Stage Configuration

34. MiTi
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