Air-Breathing Laser Heat Engine Using Solid Absorbers
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Solution Overview
Problem
Existing methods for powering unmanned aerial vehicles (UAVs) with laser-powered heat engines face limitations due to wavelength and power density constraints of photonic receptors and inefficiencies in using ambient air as a working fluid, particularly with direct absorption leading to low absorption and molecular disassociation at high power densities.
Innovation Solution
An open-cycle, air-breathing heat engine that uses ambient air as the working fluid, where laser radiation is absorbed by solid absorbers and transferred to heat exchangers, heating the air without direct absorption, allowing for longer wavelength lasers and improved efficiency by avoiding chemical changes or plasma-state conversion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If direct absorption of laser radiation by ambient air is used, then power density can be increased, but absorption efficiency decreases and molecular disassociation occurs
Solution Approach 1:
The patent introduces a working fluid as an intermediary substance that absorbs laser radiation more efficiently than ambient air. This working fluid serves as a mediator between the laser energy source and the propulsion system, enabling effective energy transfer without the molecular disassociation problems that occur with direct air absorption.
2Power
If photonic receptors are used to convert laser radiation, then power can be generated, but wavelength range is limited and power density is constrained
Solution Approach 1:
The patent replaces photonic receptors (electronic conversion system) with a thermal-based heat engine system. Instead of converting laser radiation directly to electricity through semiconductor materials, the system converts laser energy to thermal energy in a working fluid, then to mechanical work, thereby eliminating semiconductor wavelength limitations.
3Quantity of substance
If ambient air is used as working fluid with direct laser absorption, then no additional fluid needs to be carried, but absorption is insufficient and plasma state conversion occurs
Solution Approach 1:
The patent changes the physical and chemical parameters of the working fluid to optimize laser absorption. By selecting a working fluid with specific absorption characteristics matched to the laser wavelength, the system achieves reliable and efficient energy transfer without requiring plasma state conversion or carrying large quantities of fluid.
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 enables reliable and efficient remote powering of UAVs and other vehicles within the terrestrial atmosphere, overcoming previous limitations by utilizing ambient air as a sustainable and abundant resource, enhancing power density and wavelength compatibility, and reducing complexity and inefficiency.
Implementation Method 1
laser radiation is absorbed by solid absorbers
Implementation Method 2
transferred to heat exchangers, heating the air
Implementation Method 3
harvesting mechanical work from expanding working fluid in the heat engine
Data Source
AI summary
Methods of powering a heat engine with a remote lasers are disclosed, where the ambient air surrounding the engine is used as the working fluid. All methods include inputting the ambient air into the engine, absorbing laser optical radiation, turning it into heat, supplying the heat to the air, harvesting mechanical work from expanding air and releasing the air back into surrounding atmosphere.