Harnessing their Hydrophobic Potential to Provide ... · Harnessing their Hydrophobic Potential to...

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Session:

Rare-earth Oxides:

Harnessing their Hydrophobic Potential to

Provide Infrastructural Upgrades in

Hydropower Plants

Sami Khan | Advisor: Kripa K. Varanasi

Ph.D. Candidate in Mechanical Engineering ‘16

Massachusetts Institute of Technology

Wettability overview

Most previous research has focused on developing more complex surface

textures; only few have address the key challenge of robust hydrophobic

materials.

1

Hydrophobicity applications

Steam turbines:

reducing moisture-

induced efficiency

losses

Condensers:

increasing heat transfer by

promoting dropwise

condensation

Aircrafts & wind turbines:

preventing ice formation

and degradation due to

erosion

Minimizing Food Waste Resisting drop impact

2

Lack of robust hydrophobic materials

Although durable materials such as metals and ceramics, which are generally

hydrophilic, can be rendered hydrophobic by polymeric modifiers, these

deteriorate in harsh environments.

1 mm

3

Can we find a material that is both robust

and intrinsically hydrophobic and derive

viable applications for hydropower?

4

Hydrophobic Rare Earth Oxides

5

Adhesion Layer for Improving Longevity

6

With Adhesion LayerWithout Adhesion Layer

Problem with Typical Coatings

7

Longevity of Rare-earth Oxide Coatings

8

Applications to Hydropower

9

Anti-Biofouling

Anti-Corrosion/ErosionScale Resistance

Drag Reduction

Conclusions and Recommendations

• Hydrophobic rare-earth oxide coatings present an attractive

multi-dimensional array of enhancements for the hydropower

industry

• These benefits include: bio-fouling resistance, drag reduction,

corrosion and erosion resistance, and overall, a reliable, long-

term form of protection

• Further research to evaluate the long-term capital and

operating costs and justify benefits for a typical plant, as well

as prove longevity and versatility of applications

• These coatings can be retrofitted in existing systems or

applied in new plants, and should be considered by

hydropower facilities in the overall scheme of infrastructure

modernization.

10

Thank you for your attention!

Contact: khansami@mit.edu

12

Robustness: Abrasive Wear Resistance

5 mm

Sustained hydrophobicity after abrasive wear

Robustness: Thermal Stability

2 mm

2 mm

Sustained hydrophobicity after high temperature exposure

Hydrophobicity applications

Steam turbines:

reducing moisture-

induced efficiency

losses

Condensers:

increasing heat transfer by

promoting dropwise

condensation

Aircrafts & wind turbines:

preventing ice formation

and degradation due to

erosion

Minimizing Food Waste Resisting drop impact

15