Hydrogen Fuel Pumping and Metering for Supercritical Turbine Combustion
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Solution Overview
Problem
Pumping hydrogen at the necessary temperature, pressure, and flow rate required by a gas turbine engine is challenging, especially when stored as a liquid.
Innovation Solution
A fuel system comprising a fuel pump that operates on liquid hydrogen to provide supercritical hydrogen fuel downstream, with a fuel metering unit that controls fuel flow to ensure the required parameters, including a variable flow area and separate throttle valves for each injector to ensure equal distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If hydrogen is stored as liquid to improve density, then fuel density is improved, but pumping difficulty increases due to challenging temperature and pressure requirements
Solution Approach 1:
The system changes the physical state parameters of hydrogen by pumping it to supercritical conditions (temperature above critical temperature and pressure above critical pressure). This transforms the hydrogen from liquid to supercritical state, which maintains high density while improving pumpability and eliminating the need for complex cryogenic pumping systems.
Solution Approach 2:
The fuel pump facilitates a phase transition from liquid hydrogen to supercritical hydrogen. By applying sufficient pressure and temperature above critical values, the system transitions the hydrogen phase to supercritical, which resolves the contradiction between maintaining high density and achieving ease of pumping.
2Ease of operation
If hydrogen is pumped to supercritical conditions, then ease of pumping is improved, but device complexity increases due to additional conditioning requirements
Solution Approach 1:
The supercritical hydrogen fuel serves itself by maintaining its own combustion readiness. Once in supercritical state, the hydrogen requires no further heating or pressurizing conditioning before combustion, as the supercritical state directly enables efficient combustion. This eliminates the need for additional conditioning equipment.
Solution Approach 2:
The invention extracts and eliminates the need for additional heating or pressurizing equipment by incorporating the conditioning function directly into the fuel pump operation. The pump itself provides the necessary supercritical conditions, removing the need for separate conditioning systems.
3Device complexity
If a single fuel metering unit is used, then device complexity is reduced, but flow distribution uniformity deteriorates due to uneven heat pickup through metering valve
Solution Approach 1:
The fuel metering system is segmented into multiple independent throttle valves, one for each fuel injector passage. This segmentation allows each valve to independently control the fuel flow to its respective injector, compensating for uneven heat pickup and ensuring uniform flow distribution across all burners despite variations in thermal conditions.
Solution Approach 2:
Each throttle valve is positioned locally at its respective fuel injector passage, allowing localized control of fuel flow. This local quality approach enables individual adjustment of fuel delivery to each burner, accounting for specific thermal conditions at each location and ensuring uniform overall distribution.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables direct combustion of hydrogen in the gas turbine engine combustor without additional heating or pressurizing, maintaining supercritical conditions for efficient fuel delivery.
Implementation Method 1
the fuel pump is configured to provide hydrogen at an outlet above a critical temperature and pressure, to thereby provide supercritical hydrogen fuel downstream
Implementation Method 2
The fuel metering unit may comprise a throttle valve configured to provide a variable pressure reduction between an inlet and an outlet
Implementation Method 3
a gas turbine engine configured to combust hydrogen fuel
Data Source
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AI summary
A fuel system for a gas turbine engine (103) configured to combust hydrogen fuel is disclosed. The fuel system comprises a main fuel conduit (226) and a fuel pump (224) configured to operate on liquid hydrogen within the fuel conduit (226) to provide pressurised fuel to a combustor (236) of the gas turbine engine (103). A fuel metering unit (248) is configured to control fuel flow delivered to the combustor (236). The fuel pump (224) is configured to provide hydrogen at an outlet above a critical temperature and pressure, to thereby provide supercritical hydrogen fuel downstream. The fuel metering unit (248) is configured to provide a variable flow area downstream of the pump (224), to deliver fuel at required flow parameters.