Hybrid Turbomachine Fluid Cooling Circuit for Lower Weight and Drag
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Solution Overview
Problem
Conventional air and oil heat exchangers in turbomachines are heavy, increase aerodynamic drag, and raise energy consumption due to their size and weight, while thermodynamic heat pumps reduce head losses but increase energy costs and weight.
Innovation Solution
A hybrid cooling system combining a passive third heat exchanger with an active refrigerant fluid circuit, including a compressor, expander, and heat exchangers, allowing for efficient heat transfer and reducing the need for the refrigerant fluid circuit during low cooling demands, thereby minimizing weight and energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If air and oil heat exchangers are used to cool the oil circuit, then heat exchange effectiveness is improved, but weight and size increase significantly
Solution Approach 1:
The patent replaces the conventional air-oil heat exchanger with a thermodynamic heat pump system that uses a refrigerant fluid cycle. This substitution allows for more efficient heat transfer with reduced component size and weight, as the heat pump can achieve higher temperature differences and better cooling performance in a more compact configuration.
Solution Approach 2:
The invention changes the operating parameters by using a refrigerant fluid with specific thermodynamic properties that allow for efficient heat absorption from the oil and heat rejection to the air. By optimizing the refrigerant cycle parameters (pressure, temperature, phase changes), the system achieves effective cooling with significantly reduced heat exchanger size and weight compared to conventional direct air-oil heat exchangers.
2Temperature
If air and oil heat exchangers are used to cool the oil circuit, then cooling performance is improved, but aerodynamic drag increases
Solution Approach 1:
The patent replaces the bulky air-oil heat exchanger with a compact thermodynamic heat pump system. This substitution reduces the physical footprint and aerodynamic profile of the cooling system, thereby minimizing interference with the air stream and reducing aerodynamic drag on the turbomachine while maintaining effective oil cooling performance.
Solution Approach 2:
The invention reconfigures the cooling system architecture by moving from a direct air-oil heat exchange approach to a refrigerant-mediated thermal cycle. This dimensional and architectural change allows the cooling function to be achieved with components that have a smaller aerodynamic footprint, reducing drag while maintaining cooling effectiveness through the refrigerant's phase change and heat transfer properties.
3Loss of energy
If thermodynamic heat pump is used to reduce head losses, then cooling system size is reduced, but energy consumption increases
Solution Approach 1:
The patent utilizes phase transitions of the refrigerant fluid (evaporation and condensation) as the core mechanism for heat transfer. During evaporation, the refrigerant absorbs latent heat from the oil, and during condensation, it releases latent heat to the air. This phase change mechanism enables highly efficient heat transfer with minimal temperature differences, reducing head losses and improving overall system efficiency compared to conventional heat exchangers that rely on conduction and convection alone.
Solution Approach 2:
The invention optimizes the refrigerant cycle parameters to maximize the coefficient of performance (COP) of the heat pump system. By carefully selecting operating pressures, temperatures, and refrigerant properties, the system achieves efficient heat transfer that reduces head losses in the oil circuit while minimizing the energy input required to drive the compressor, thereby balancing the trade-off between reduced head losses and energy consumption.
4Area of stationary object
If thermodynamic heat pump is used to reduce head losses, then heat exchanger surface area is reduced, but system weight increases
Solution Approach 1:
The patent replaces the large-surface-area air-oil heat exchanger with a thermodynamic heat pump system that uses refrigerant phase changes for heat transfer. This substitution allows for significantly reduced heat exchanger surface area because the refrigerant's latent heat of evaporation and condensation enables highly efficient heat transfer in compact evaporator and condenser components, thereby reducing the overall system weight despite the addition of the refrigerant cycle machinery.
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 hybrid system reduces weight and energy costs, maintains performance, and extends the lifespan of components by selectively using the refrigerant fluid circuit only when necessary, optimizing heat transfer and minimizing head losses.
Implementation Method 1
a second heat exchanger configured to exchange heat between the refrigerant fluid and the first fluid
Implementation Method 2
a first heat exchanger configured to exchange heat between the refrigerant fluid and air
Implementation Method 3
an expander located downstream from the first heat exchanger and upstream from the second heat exchanger in the flow direction of the refrigerant fluid
Implementation Method 4
a compressor located downstream from the second heat exchanger and upstream from the first heat exchanger
Data Source
AI summary
A cooling system for cooling a circuit of a first fluid of a turbomachine, the cooling system including a refrigerant fluid circuit including a first heat exchanger for exchanging heat between the refrigerant fluid and air, a second heat exchanger for exchanging heat between the refrigerant fluid and the first fluid, an expander located downstream from the first heat exchanger and upstream from the second heat exchanger in the flow direction of the refrigerant fluid, and a compressor located downstream from the second heat exchanger and upstream from the first heat exchanger; the cooling system further includes a third heat exchanger of the first fluid and air type.