Session: 04-05 High Hydrogen I

Paper Number: 122593

122593 - Considerations for Hydrogen Fueled Aerospace Gas Turbine Combustion Sub-System Design 

As part of its commitment to the decarbonisation of the aviation sector, Rolls-Royce is actively developing hydrogen combustion gas turbine engine technology capable of powering a range of aircraft from the mid-2030s onwards. These innovative technologies are undergoing integration and validation through a demonstrator project, which involves the modification of a Pearl-15 engine for ground testing using both gaseous and liquid hydrogen.

The design of an aerospace combustor needs to satisfy conventional requirements such as cost, weight, aero-thermal performance and lifespan. However, the introduction of hydrogen as the primary fuel introduces additional challenges, including potential novel failure modes, operability considerations and pollutant emissions. with potentially novel failure modes, operability considerations and pollutant emissions.

The NOx emissions resulting from hydrogen combustion are currently the subject of extensive research and are considered to be one of the key considerations which will ultimately influence the design of the optimum hydrogen combustion sub-system for aerospace applications. There are a number of potential design possibilities, but the central question remains as to which is the most appropriate for an aerospace product.

This paper outlines the requirements of a hydrogen fuelled aviation product in terms of NOx emissions and describes the development of the first prototype combustion technology at Rolls-Royce. Innovative fuel injection concepts were developed to enable operation with 100% hydrogen on the Pearl 15 combustor architecture. The paper details the process of initial development on a single sector atmospheric test rig, including a design of experiments approach to map the design space and understand sensitivities. This process led to the selection of four leading configurations based on NOx emissions, flame stability measurements using optical, UV, and infrared methods, as well as ignition and weak extinction performance.

The paper then proceeds to describe intermediate pressure rig testing, which was conducted at engine-representative low power conditions. This testing aimed at identifying challenges related to flame stability and combustor temperature distribution using optical measurement methods, thereby mitigating risks associated with engine combustor testing. Finally, it discusses tests undertaken in a full annular, high pressure combustion rig at engine-representative maximum take-off conditions.

Aerothermal performance, as measured by NOx emissions, weak extinction and exit temperature traverse, demonstrated promising comparisons to kerosene-based experience. These results, in conjunction with sector rig testing and numerical predictions, suggest significant progress not only in hydrogen combustion technology development but also in numerical and experimental capabilities.

The tests confirm the feasibility of an aerospace combustion system with 100% Hydrogen with acceptable NOx emissions and no thermoacoustic resonances. This marks a major milestone for the Rolls-Royce Hydrogen Accelerator program, facilitating progress toward an engine test with 100% gaseous hydrogen in the near future.

Rolls-Royce receives support for hydrogen research through the UK’s Aerospace Technology Institute HyEST programme, Germany’s LUFO 6 WOTAN programme, and the European Union’s Clean Aviation CAVENDISH programme.

Presenting Author: Carsten Clemen Rolls-Royce Deutschland Ltd Co KG

Presenting Author Biography: Dr. Carsten Clemen, born 1975, works since 2001 for Rolls-Royce Deutschland, he received his PhD from Technical University on the topic of three-dimensional inverse compressor blade design, Carsten worked in several roles in Compressor and External Aerodynamics before joining the Combustion team in 2012.
Carsten is a Business Specialist for Combustion Experimental Methods and he is project lead for the so called Low Emission Rich Burn Programme as well as for the Rolls-Royce Deutschland part of the Hydrogen Combustion Development Programme.

Authors:

Carsten Clemen Rolls-Royce Deutschland Ltd Co KG
Murthy Ravikanti Rolls-Royce plc
Nicholas La Bianca Rolls-Royce plc
Ruud Eggels Rolls-Royce Deutschland Ltd Co KG
Benno Wurm Rolls-Royce Deutschland Ltd Co KG
Ken Young Rolls-Royce plc