Hydrogen Fuel System With Turbine-Driven Pump And Bypass Control
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Solution Overview
Problem
Challenges in conditioning liquid hydrogen for hydrogen fuelled aircraft include the high power required to raise temperatures and pressures at the required flow rate, as well as controlling complex pumping and heating systems to produce the necessary flow, pressures, and temperatures at all phases of flight.
Innovation Solution
A fuel system for a gas turbine engine comprising a main fuel conduit, a fuel pump, an auxiliary combustor, a fuel turbine, and a turbine bypass conduit, which efficiently conditions fuel by using the fuel turbine to drive the pump, with optional electric motor support, and includes a controller for independent control of temperature and pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If liquid hydrogen is used as fuel storage, then fuel density is improved, but high power is required to raise temperature and pressure at required flow rates
Solution Approach 1:
The fuel turbine utilizes the heated fuel itself to drive the fuel pump, creating a self-service system where the fuel preparation process powers its own delivery system. The turbine extracts energy from the high-temperature fuel stream to drive the pump, reducing external power requirements.
Solution Approach 2:
The system converts the high temperature of the heated fuel, which would otherwise be wasted energy, into useful mechanical work to drive the fuel pump. The thermal energy that needs to be managed becomes the power source for fuel delivery.
2Reliability
If complex pumping and heating systems are used to condition liquid hydrogen, then required flow and pressure are achieved, but system complexity increases
Solution Approach 1:
The system merges the fuel heating process with fuel pump operation by using the heated fuel to drive a turbine that powers the pump. This integration reduces the number of independent systems required and simplifies the overall fuel conditioning architecture.
Solution Approach 2:
The heated fuel serves multiple functions: it provides thermal energy for combustion preparation and simultaneously drives the fuel pump through the turbine. This multi-functionality reduces the need for separate power sources and simplifies system design.
3Power
If fuel turbine is used to drive fuel pump, then power efficiency is improved, but control flexibility may be reduced
Solution Approach 1:
The system dynamically adjusts fuel flow distribution between the turbine and bypass paths based on operational requirements. The bypass valve provides continuous adjustability, allowing the system to optimize between turbine-driven efficiency and direct pump control as conditions change.
Solution Approach 2:
The bypass valve acts as an intermediary control element that regulates the balance between fuel flowing through the turbine and fuel bypassing it. This mediator allows independent control of the turbine-driven pump while maintaining overall system flexibility.
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
The system efficiently and controllably conditions fuel, providing efficient driving power to the pump, allowing independent temperature and pressure control, and utilizes excess energy, while maintaining consistent fuel flow and pressure across varying flight conditions.
Implementation Method 1
an auxiliary combustor downstream in fuel flow of the fuel pump, and configured to combust a portion of fuel diverted from the main fuel conduit and to heat a remainder of fuel in the main fuel conduit
Implementation Method 2
a fuel turbine downstream in fuel flow of the auxiliary combustor, the fuel turbine being configured to be driven by the heated fuel from the auxiliary combustor
Implementation Method 3
a fuel pump configured to operate on hydrogen within the fuel conduit to provide pressurised fuel to a core combustor of the gas turbine engine
Data Source
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AI summary
A fuel system for a gas turbine engine (103) configured to combust hydrogen fuel. The fuel system comprises a main fuel conduit (226), a fuel pump (224) configured to operate on hydrogen within the fuel conduit (224) to provide pressurised fuel to a core combustor (236) of the gas turbine engine (103), an auxiliary combustor (228) downstream in fuel flow of the fuel pump (224), and configured to combust a portion of fuel diverted from the main fuel conduit (224) and to heat a remainder of fuel in the main fuel conduit (224), and a fuel turbine (234) downstream in fuel flow of the auxiliary combustor (228). The fuel turbine (234) is configured to be driven by the heated fuel from the auxiliary combustor (228) and configured to power the fuel pump (224). The fuel system comprises a turbine bypass conduit (240) configured to selectively bypass fuel around the fuel turbine (234). A method of operation is also described.