1

2

Thermal Barrier Coating Applied to the

Structural Shroud of the Inside-Out Ceramic Turbine

Patrick K. Dubois1, Benoît Picard2, Antoine Gauvin-Verville1, Dominik Thibault1, Jean-Sébastien Plante1, Mathieu Picard1

1Createk Design Lab, Université de Sherbrooke (Canada)2Exonetik, Turbo Division (Canada)

The ICT rotor configuration converts

compressive loading in ceramic blades1

to hoop stresses in an air-cooled

rotating composite structural shroud2

Thermal Barrier Coating in the ICT could

1. Reduce cooling requirements

2. Increase TIT capability

3. Eliminate hot spots in cooling ring

4. Keep the ceramic blades at a higher operating

temperature

2

TBC

Does the ICT configuration support TBC?

1. Hoop Strain

2. Blade Indentation

Slope = 1

TBC

Spalling

complete

Spalling begins

Substrate yields

Substrate Strain

TBC

Strain

0.98%

Universal Testing Machine

3D Image Correlation System

Camera 1 Camera 2

Load Cell

Sample

Motivation• The composite matrix limits Turbine Inlet

Temperature, Tmax ≈ 320 °C

• Cooling flow significantly reduces cycle

efficiency and counteracts TIT gains

• Relatively cold blade induces local stresses

In-plane compliance

TBC adheres to substrate

until yield, with no effect

on elastic properties

So what?

The entire elastic range is

available for designing the

cooling ring

What is the Inside-Out Ceramic Turbine? ICT

TBCTIT

Hydraulic Press

Load Cell

Indenter

Sample

High out-of-plane strength

Tested TBC resists

indentation up to 1000 MPa

So what?

TBC will withstand the

centrifugal loading of the

ceramic bladesIndenter Pressure (MPa)

1000 2800

70

Damage

Depth

(µm)

Damage Range

0

ICT Operating

Range

0 10

Shroud Cooling

(% of compressor output)

Cycle

efficiency

(%)

TIT

38

49

TBC

Rotor Testing

ICT Loads

Test conditions

• 5 minutes at TIT = 900 °C

• 3D-printed Inconel 718 Blades

• 1mm TBC thickness

• 80 000 RPM

Test Results

✓50% reduction in cooling flow

✓No damage to TBC

! Composite hoop split due to

added mass

Approach Results

Compressive

Loading

Rotating

Structural

Shroud

ICT

Dovetail

Tensile

Loading

1

Rotor Hub

Structural Shroud

Carbon-Polymer

Blades slide up and

down the dedicated

track to compensate

displacement

Radial displacement

under centrifugal loadTIT > 1200 °C

Ceramic Blades

Shroud-Cooling

Confocal Microscopy

ConclusionsThe Inside-Out Ceramic Turbine configuration

supports TBC thanks to its orthotropic behaviour

TBC should allow the use of lightweight Ti alloy

shroud-cooling, allowing higher RPMs and

lower thermal stresses

Acknowledgments

Thanks go out to personnel at École de technologie supérieure – LAMSI and development partners Exonetik Turbo.

Funding was provided by the National Sciences and Engineering Research Council of Canada (NSERC) CRD PJ 477320-14,

the Government of Quebec, Defence Research and Devlopment Canada Contract W7714-196710/001/SV.