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

Abstract Hydrogen-enriched fuel has been proposed as a cost-effective solution for continued use of the gas grid for clean electricity, despite known changes in combustion products and heat transfer. It has been tested successfully in the radial swirl-stabilized dry low-emission (DLE) combustor for the OP16 gas turbine. This study assessed the effect of hydrogen on combustor lifetime; this requires accurate temperatures as local hotspots or sharp gradients trigger various failure mechanisms. In this work, wall temperatures for two flame tubes in a radial 2MW gas turbine (tested at Destinus Energy) were measured comparing fuels (natural gas vs natural gas-hydrogen mix) with no design, fuel injection or cooling modifications. Temperatures were measured using Thermal History Coatings (THCs), applied for the first time on a combustor with hydrogen fuel. THCs relay past temperatures through luminescent measurements, output in high-resolution digitized format. Here, an improved analysis methodology for THCs was employed. Over 20,580 measured temperatures permitted a detailed insight on temperature distributions, clearly identifying the effectiveness of impingement cooling. A significant rise in heat transfer is clearly observed with the addition of hydrogen, resulting in local temperatures above typical design, thus requiring further cooling improvements for acceptable lifetime performance. The data provides a useful benchmark for the design and modelling of enhanced cooling. These findings propose the use of THCs for rapid assessment of fuel, design and cooling modifications in gas turbines.