Session: 13-01: Heat transfer in turbines engine testing

Paper Number: 152181

Utilising Thermal History Coatings for the Assessment of Hydrogen Fuel on Combustor Temperatures 

With the phasing out of natural gas, hydrogen appears to be a cost-effective solution for continuing to use the gas grid and, at the same time, to realize clean electricity and heat in the industry. The addition of hydrogen has been tested successfully in the radial swirl-stabilized dry low-emission (DLE) combustor for the OP16 gas turbine. The addition of hydrogen changes the combustion products, thus the heat transfer to the components will change. The aim of this study was to measure the effect of hydrogen on gas turbine combustors to determine the expected impact it has on the lifetime of the components. An accurate temperature map is crucial for a detailed understanding of the impact on lifetime. Local hotspots or temperature gradients could trigger various combustor failure mechanisms.

This project saw the measurement of the maximum wall temperature of two flame tubes in a radial 2MW gas turbine. The two flame tubes were tested at Destinus Energy. Two fuel configurations were compared in one test: natural gas and a natural gas-hydrogen mix respectively. Hereby the hydrogen addition has been tested on the natural gas combustor configuration, no design modifications on fuel injection or cooling were implemented.

The chosen temperature technique was the novel Thermal History Coating (THC). These thermal memory materials are uniquely able to relay past maximum temperature of exposure across a component surface. This technique sees the application of a robust, luminescent coating via Atmospheric Plasma Spray. After heat exposure, laser-based instrumentation enables high-resolution measurements of the coating luminescence using an automated system. Through calibration, each measurement point (down to 1x1 mm resolution) is translated into temperature. This enables the objective data, in the 1,000s of points, to be provided both in its raw form and digitised on 3D models; this is vital for easy comparison against thermal models and alternative measurement techniques.

The use of Thermal History Coating brings various advantages compared to other measurement techniques. Conventionally, thermochromic paints are used which are nowadays challenging to source, typically show limited temperature transitions (in the order of 50-100 °C, which could have a major impact on lifetime predictions) and have a limited exposure time, challenging the test campaign for full-scale gas turbine tests. Thermocouples may provide very accurate local readings but cannot provide a full overview of the temperature, whereby local hot spots can be missed.

This work successfully delivered 20,581 of temperature measurements across both combustors. Temperature data was generated using the recently developed spectral method for the THCs. The results provide a detailed insight in the temperature distribution over the combustor. The impact and effectiveness of the impingement cooling can be clearly identified. The results can be used to validate and improve the calculation models. The comparison of natural gas and hydrogen-enriched natural gas clearly indicate that the heat transfer is enhanced significantly by the addition of hydrogen. Locally, temperatures are observed above typical design temperatures for combustor parts. This indicates that further cooling improvements are required to increase the combustor lifetime with the addition of hydrogen. The test data provides useful input for the design process of enhanced cooling as benchmark data. These findings showcase the potential use of Thermal History Coatings in enabling rapid assessment of fuel, design and cooling modifications in gas turbines.

Presenting Author: Silvia Araguas Rodriguez Sensor Coating Systems

Presenting Author Biography: Silvia Araguas Rodriguez is the Technical Director at Sensor Coating Systems (SCS) Limited, where she leads the technical team and delivers customer contracts to global clients. She has a background in Materials Science and Engineering with a Doctor of Philosophy from Imperial College London. Silvia has extensive experience in research and development and its implementation in industrial settings.

Authors:

Silvia Araguas Rodriguez Sensor Coating Systems
Thijs Bouten Destinus Energy
Elmira Parsa Sensor Coating Systems
Ilora Ishaque Sensor Coating Systems
Carl Parsons Sensor Coating Systems
Goran Krsic Sensor Coating Systems
Joseph Counte Sensor Coating Systems
Lars-Uno Axelsson Destinus Energy
Solon Karagiannopoulos Sensor Coating Systems
Jörg Feist Sensor Coating Systems