Micro-Turbine Thermal Isolation for Generator Heat Protection
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Solution Overview
Problem
Micro-turbine alternators face challenges in efficiently managing thermal exposure, which can lead to demagnetization of permanent magnets in electric generators due to heat from the turbine, limiting their operational duration and efficiency, especially in applications like unmanned aerial vehicles (UAVs) where lightweight and high-power density are crucial.
Innovation Solution
The implementation of a turbine thermal isolation system using forced air cooling and ceramic thermal isolators to protect the electric generator from heat, combined with a blower that directs airflow through the generator cavity and turbine, effectively reducing operating temperatures and preventing heat transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the electric generator is placed close to the turbine for compact design, then the device complexity is reduced, but the temperature of the electric generator increases due to heat exposure from the turbine
Solution Approach 1:
A blower is introduced as an intermediary component between the turbine and electric generator. The blower forces cooling air through the generator cavity, creating a thermal barrier that protects the electric generator from turbine heat while maintaining the compact integrated design. This mediator component enables close proximity placement without direct thermal contact.
Solution Approach 2:
The system uses pneumatic cooling by forcing air flow through the generator cavity using the blower. This pressurized air flow carries heat away from the electric generator, allowing the system to maintain compact dimensions while actively managing thermal exposure through fluid dynamics.
2Device complexity
If conventional internal combustion engines are used for power generation, then the device complexity is reduced, but the loss of energy increases due to inefficiency at low power levels
Solution Approach 1:
The system changes the operating parameters by using a micro-turbine alternator operating in the 1-30 KW power range, where turbines are inherently more efficient than conventional engines. This parameter change in power level and mechanism type reduces energy loss while maintaining practical complexity for UAV applications.
3Device complexity
If batteries are used for power supply, then the device complexity is reduced, but the duration of action is limited due to low energy density
Solution Approach 1:
The system changes the power source parameter from chemical energy storage (batteries) to thermal-to-mechanical energy conversion (micro-turbine). This parameter change enables sustained operation for medium-sized UAVs by providing continuous power generation capability with higher energy density than batteries in the 1-30 KW range.
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 significantly reduces the operating temperature of the electric generator, increases the critical speed of the turbine shaft, and enhances the stiffness of the rotating components, thereby extending the operational duration and improving the efficiency of the micro-turbine alternator system.
Implementation Method 1
The blower is configured to blow air through the generator cavity through or around the electric generator. The air is configured to exit the generator cavity to enter the turbine.
Implementation Method 2
a turbine thermal conduction choke located between the turbine shaft disc and the turbine. The turbine thermal conduction choke has a smaller outer diameter than remaining portions of the turbine shaft, the turbine shaft disc, and the turbine.
Data Source
AI summary
An electrical power generation system including: a micro-turbine alternator, including: a decomposition chamber; a turbine including blades driven by combustion gases from the decomposition chamber; a blower operably connected to the decomposition chamber to provide a blown airflow thereto; one or more shafts connecting the turbine to the blower such that rotation of the turbine drives rotation of the blower; an electric generator disposed along the one or more shafts such that electrical power is generated via rotation of the one or more shafts; and a housing enclosing the electric generator within a generator cavity formed therein. The blower is configured to blow air through the generator cavity through or around the electric generator. The air is configured to exit the generator cavity to enter the turbine.