Micro-Turbine Recuperator and Bottoming Cycle for Low-Power UAVs
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Solution Overview
Problem
Unmanned aerial vehicles (UAVs) and similar systems face short mission times due to low energy density of batteries and inefficiency of conventional engines at low power levels, limiting their operational height and distance, and there is a need for a lightweight, high power density power source.
Innovation Solution
A micro-turbine alternator system with a multi-stage turbine, recuperator, thermal electric generator array, and bottoming system that utilizes a catalytic converter to enhance efficiency and reduce fuel consumption, while integrating a waste heat recovery and inlet pressure boost system to optimize power generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional internal combustion engines are used for low power levels (1 KW to 30 KW), then the system can provide mechanical propulsion, but the engine efficiency becomes very low
Solution Approach 1:
The patent replaces the conventional mechanical internal combustion engine with a micro-turbine system that operates on a different thermodynamic principle (Brayton cycle). This substitution enables efficient operation at low power levels (1-30 KW) where traditional engines fail, achieving both high power density and acceptable efficiency through aerodynamic compression and expansion processes rather than purely mechanical piston operations
Solution Approach 2:
The patent changes the operating parameters by using a micro-turbine design optimized for low-power Brayton cycle operation. The system operates at rotational speeds and pressure ratios suitable for the 1-30 KW range, fundamentally altering the operational regime from conventional engine parameters to turbine parameters that are more efficient at these power levels
2Use of energy by moving object
If batteries are used to provide electrical power, then the system can operate electrically, but the energy density is far too low to effectively work in the 1 KW to 30 KW power range
Solution Approach 1:
The patent substitutes battery-based electrical power systems with a micro-turbine-based power generation system. This replacement provides continuous operational capability at 1-30 KW power levels with effectively unlimited duration, overcoming the fundamental energy density limitations of battery systems while maintaining electrical power output
3Duration of action of moving object
If a tethered UAV system is used to increase mission duration, then the UAV can operate longer, but the operating height and distance are reduced due to the tether constraint
Solution Approach 1:
The patent extracts and eliminates the tether constraint by implementing an autonomous micro-turbine power source on the UAV itself. This removal of the external power connection enables the UAV to operate freely in three-dimensional space without height or distance limitations imposed by tether length, while the micro-turbine provides unlimited mission duration
4Power
If a micro-turbine alternator system is used to provide high power density, then the system achieves efficient power generation, but the device complexity increases with multiple components
Solution Approach 1:
The patent merges multiple functions into integrated components: the micro-turbine alternator combines compression, combustion, expansion, and electricity generation in a single rotating assembly; the waste heat recovery system integrates heat exchangers that simultaneously preheat combustion air and generate additional power; the catalytic converter combines emissions treatment with heat recovery. These mergers reduce overall system complexity while maintaining high power density
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 system increases mission duration by providing a high power density, efficient, and lightweight power source, reducing fuel consumption, and enhancing the operational efficiency and power density of UAVs and similar systems.
Implementation Method 1
a recuperator configured to transfer heat from the exhaust exiting the at least one turbine to the compressed airflow from the at least one compressor entering the combustor
Implementation Method 2
The thermo electric device being configured to generate an electrical current based on a temperature difference between the cold side heat transfer surface and the hot side heat transfer surface
Implementation Method 3
a hot side passageway configured to receive the exhaust from the recuperator, a hot side heat transfer surface thermally connected to the hot side passageway
Implementation Method 4
a cold side passageway configured to transfer air to the at least one compressor, a cold side heat transfer surface thermally connected to the cold side passageway
Data Source
AI summary
The electrical power generation system including a micro-turbine alternator. The micro-turbine alternator including a combustor, at least one turbine configured to be driven by an exhaust from the combustor, at least one compressor operably connected to the combustor to provide a compressed airflow to the combustor, one or more shafts connecting the at least one turbine to the at least one compressor such that rotation of the at least one turbine drives rotation of the at least one compressor, and a recuperator configured to transfer heat from the exhaust exiting the at least one turbine to the compressed airflow from the at least one compressor entering the combustor.