Assessment of an Integrated Fuel Metering Valve Control System for a Hydrogen-Powered Aero Engine

Hydrogen-fuelled gas turbine engines require accurate fuel metering, but relative to kerosene systems, gaseous hydrogen introduces greater uncertainty in fuel-flow measurement and metering accuracy. This simulation-based study investigates a sonic hydrogen fuel metering valve (FMV) integrated into a hydrogen-fuelled turboshaft engine to model and evaluate alternative control strategies. Focusing on fuel-flow controllability, pressure management, disturbance sensitivity and inlet-temperature effects, it provides an original closed-loop, system-level analysis framework coupling the FMV with the engine power controller. The adopted sonic FMV reduces the minimum upstream-to-downstream pressure ratio for choking to 1.32, compared with 2.08 for a conventional design, with a 10% margin applied to both values, thereby reducing the high-pressure (HP) pump pressure requirement. Fixed- and variable-pressure delivery schemes achieved satisfactory fuel-flow tracking with an absolute relative cumulative error of 0.1%. The fixed-pressure scheme provided closer transient agreement, whereas the variable-pressure scheme reduced part-load HP-pump power by up to 67–85%. This study provides a systematic analysis of measurement-uncertainty disturbances in an end-to-end hydrogen fuel system, demonstrating that FMV dynamics effects vary with the disturbance pathway: HP-pump pressure-feedback uncertainty produced the largest FMV dynamic deviations in fuel flow, high-pressure compressor exit pressure, and combustor outlet temperature, compared with power-turbine feedback and FMV inlet-temperature uncertainty. These findings indicate robust hydrogen fuel system design and control should prioritise validated and filtered power-feedback measurements, pressure sensing close to the FMV inlet, monitoring of the FMV pressure ratio to preserve the choking margin and FMV inlet temperature measurement to maintain metering authority.