Combustible Cooling Fluid as Secondary Fuel Source
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Solution Overview
Problem
Aircraft systems face challenges in efficiently managing high heat loads from sophisticated systems like directed energy weapons, power electronics, and communication systems, while also needing to mask the aircraft's heat envelope for military applications. Existing solutions, such as using cryogenic liquids, add significant weight and parasitic load.
Innovation Solution
The system utilizes a combustible and soluble cooling fluid, such as liquid natural gas or ammonia, which is stored in a tank and supplied to a thermal load. The cooling fluid is then mixed with aviation fuel and burned in the aircraft's gas turbine engine, eliminating the need for post-use storage and providing energy benefits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If cryogenic liquid is used as heat sink, then cooling effectiveness is improved, but weight and parasitic load increase significantly
Solution Approach 1:
The cooling fluid serves dual functions: it cools the thermal load and simultaneously acts as fuel for the gas turbine engine. This multi-functionality eliminates the need for separate storage tanks and handling systems for waste cooling fluid, significantly reducing the overall system weight and parasitic load while maintaining effective cooling performance
Solution Approach 2:
The system changes the physical and chemical parameters of the cooling fluid by selecting substances that are both effective coolants and combustible fuels. The controller adjusts the amount of cooling fluid diverted to fuel based on engine fuel requirements and thermal load conditions, optimizing the balance between cooling effectiveness and energy utilization
2Use of energy by moving object
If cooling fluid is combusted in engine, then energy utilization is improved, but mixing precision requirements increase
Solution Approach 1:
The controller continuously monitors engine operating conditions and thermal load requirements, dynamically adjusting the amount of cooling fluid diverted to the fuel system. This feedback control ensures optimal mixing ratios are maintained across varying operating conditions, preventing combustion issues while maximizing energy utilization
Solution Approach 2:
The system uses an intermediary mixing mechanism where cooling fluid is introduced into the fuel stream downstream of the fuel metering unit. This intermediary approach allows for controlled mixing of the cooling fluid with fuel without requiring precise pre-mixing, as the mixing occurs in the fuel line where turbulence and flow conditions facilitate homogeneous mixing
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
This solution effectively cools high thermal loads, reduces the aircraft's heat envelope, and provides energy benefits by utilizing the cooling fluid's energy content within the engine, all while minimizing weight and parasitic load.
Implementation Method 1
a cooling liquid... supplied to a thermal load
Implementation Method 2
The controller is programmed to determine a percentage solubility of the cooling fluid into the fuel
Implementation Method 3
The fuel metering unit is configured to deliver a mixture of the cooling liquid and the fuel into a combustor
Data Source
AI summary
An aircraft system includes a thermal load, a controller, a tank for storing a cooling liquid, and a supply system for moving the cooling liquid outwardly of the tank and through a control valve to the thermal load. A controller is programmed to control the supply system. A conduit downstream of the thermal load is configured to communicate the cooling liquid to a fuel metering unit. The fuel metering unit also receives fuel from a high pressure pump. The fuel metering unit is configured to deliver a mixture of the cooling liquid and the fuel into a combustor on an associated aircraft engine. The controller programmed to determine a percentage solubility of the cooling fluid into the fuel at a detected temperature and pressure of the fuel reaching the fuel metering unit. The cooling fluid is combustible and soluble in the fuel. An aircraft and a method are also disclosed.