Hydrogen Fuel System Preheating to Reduce Pump Cavitation
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Solution Overview
Problem
Pumping liquid hydrogen in gas turbine engines requires high power and is prone to cavitation due to the risk of forming bubbles, which can damage equipment and increase pumping work, especially in varying external pressures during flight.
Innovation Solution
A fuel system that includes a pre-heater to heat hydrogen downstream of the pump, a return line to maintain tank pressure, and a mixer to control the temperature and phase of the returned hydrogen, along with multiple pumps in series to manage pressure and reduce cavitation risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If liquid hydrogen is pumped at high flow rates and pressures, then sufficient fuel delivery to the gas turbine is achieved, but high power is required and cavitation risk increases
Solution Approach 1:
The system pre-heats the liquid hydrogen before it enters the pump, raising its temperature and reducing its viscosity. This preliminary thermal treatment makes the hydrogen easier to pump, reducing the power required by the pump while maintaining the necessary flow rates for fuel delivery.
Solution Approach 2:
The invention changes the temperature parameter of the hydrogen fuel by heating it before pumping. This parameter change reduces the density and viscosity of the hydrogen, allowing the pump to operate more efficiently with lower power consumption while achieving the required productivity.
2Productivity
If liquid hydrogen is pumped at high flow rates and pressures, then sufficient fuel delivery to the gas turbine is achieved, but cavitation within the pump increases
Solution Approach 1:
The system pre-heats the liquid hydrogen before it enters the pump, raising its temperature and reducing its viscosity. This preliminary thermal treatment makes the hydrogen easier to pump, reducing the power required by the pump while maintaining the necessary flow rates for fuel delivery.
Solution Approach 2:
The invention changes the temperature parameter of the hydrogen fuel by heating it before pumping. This parameter change reduces the density and viscosity of the hydrogen, allowing the pump to operate more efficiently with lower power consumption while achieving the required productivity.
3Ease of operation
If hydrogen is heated before delivery to the gas turbine, then combustion is enabled and icing is prevented, but additional heating energy is required
Solution Approach 1:
The system combines the heating function with the fuel delivery system by using a heat exchanger that is integrated into the fuel line. This allows the hydrogen to be heated during its normal flow path without requiring a separate heating system, thereby enabling combustion while minimizing additional energy requirements through efficient heat transfer.
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
Maintains positive tank pressure and prevents cavitation, reducing equipment damage and pumping work, allowing for efficient hydrogen delivery to the gas turbine engine.
Implementation Method 1
a pre-heater configured to heat at least a portion of pressurised hydrogen fuel downstream of the pump
Implementation Method 2
a pump configured to provide pressurised hydrogen at an outlet thereof
Data Source
AI summary
A fuel system for a hydrogen fuelled gas turbine engine comprises a tank configured to store hydrogen, a pump configured to provide pressurised hydrogen at an outlet thereof, and a pre-heater configured to heat at least a portion of pressurised hydrogen fuel downstream of the pump. A preheater return offtake is configured to return at least a portion of hydrogen fuel heated by the preheater to the tank.