s-CO2 Gas Turbine Engine with Independent Shafts
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Solution Overview
Problem
Gas turbine engines are inefficient due to low-density air operation, leading to large and heavy components, high fuel consumption, and increased operational and maintenance costs, as they require significant power to compress and heat air to high pressures and temperatures for propulsion and power generation.
Innovation Solution
Implementing a super-critical carbon dioxide (s-CO2) system in a closed-loop cycle that operates above the critical point of CO2, allowing for a dense, efficient power source with optimized rotational speeds for each component, reducing system size and improving thermodynamic efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If air is compressed to very high pressure ratios and heated to very high temperatures to achieve needed power output, then the power output is sufficient, but the engine size and weight increase significantly
Solution Approach 1:
The patent changes the working fluid from air to supercritical carbon dioxide (sCO2), fundamentally altering the thermodynamic parameters of the cycle. sCO2 operates at higher densities and allows for more efficient heat transfer, enabling the same power output with smaller, lighter components. The critical point of CO2 (31°C, 73 atm) is exploited to achieve superior thermodynamic performance compared to air-based Brayton cycles.
Solution Approach 2:
The invention employs a closed-loop sCO2 Brayton cycle system with dedicated compression, heat addition, expansion, and heat rejection components. The sCO2 fluid is circulated through these pneumatic/hydraulic components in a continuous cycle, replacing the open-loop air intake and exhaust system. This closed-loop approach with sCO2 enables higher efficiency and compact component design.
2Quantity of substance
If significant volume flow rate of low density air is pumped through high pressure ratio, then adequate mass flow rate is achieved, but significant power is consumed
Solution Approach 1:
The patent changes the working fluid from low-density air to high-density supercritical CO2. The sCO2 maintains high density across the operating range, significantly reducing the volumetric flow rate required to achieve the same mass flow rate. This reduces the power consumption of compressors and the overall size of the system while maintaining adequate mass flow for heat transfer and power generation.
3Power
If high combustion temperatures are used to achieve needed power output, then power output is sufficient, but operational and maintenance expenses increase
Solution Approach 1:
The patent modifies the thermal cycle parameters by using sCO2 as the working fluid, which allows for efficient heat addition at lower peak temperatures compared to conventional air-breathing combustion cycles. The sCO2 Brayton cycle can achieve high thermal efficiency with reduced combustion temperatures, lowering thermal stresses on components and reducing maintenance requirements while maintaining power output.
4Volume of stationary object
If s-CO2 system is implemented to reduce component size, then system size is reduced, but system complexity increases
Solution Approach 1:
The patent divides the sCO2 Brayton cycle into distinct functional segments: sCO2 compression system, heat addition system (combustor or heat exchanger), expansion system (turbine), and heat rejection system. Each segment is independently optimized and can be separately maintained or replaced, managing system complexity through modular segmentation while achieving compact overall size.
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 s-CO2 system significantly reduces engine size and complexity while enhancing power density and overall efficiency, allowing for flexible propulsion system design and reduced fuel consumption across various flight regimes.
Implementation Method 1
a phase-diagram of CO2, as is commonly known, includes a 'triple point' as the point that defines the temperature and pressure where solid, liquid, and vapor meet. Above the triple point the fluid can exist in liquid, vapor, or in a mixture of the both states. However, at higher temperature and pressure, a critical point is reached which defines a temperature and pressure where gas, liquid, and a super-critical region occur.
Data Source
AI summary
A gas turbine engine includes a first shaft coupled to a first turbine and a first compressor, a second shaft coupled to a second turbine and a second compressor, and a third shaft coupled to a third turbine and a fan assembly. The turbine engine includes a heat rejection heat exchanger configured to reject heat from a closed loop system with air passed from the fan assembly, and a combustor positioned to receive compressed air from the second compressor as a core stream. The closed-loop system includes the first, second, and third turbines and the first compressor and receives energy input from the combustor.