Laser-Powered UAV Heat Engine Using Optical Absorber

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

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, inefficiencies in air-breezing heat engines, and the need for consumable working fluids.

Innovation Solution

The use of laser-powered heat engines that absorb optical radiation to heat a working fluid, replacing traditional fuel combustion with laser-generated heat, and employing fiber-optic power delivery systems to optimize heat transfer and efficiency, including the use of highly absorptive working fluids and synchronized pulsed laser power to enhance engine performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If semiconductor photonic receptors are used to convert laser photons into electricity, then power conversion is achieved, but the wavelength range is limited to approximately 2 micrometers or less due to low photon energy at longer wavelengths

Engineering Contradiction:

Improvewavelength conversion rangeVSAvoidpower conversion efficiency

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent replaces semiconductor photonic receptors with a thermal conversion system consisting of an optical absorber and heat engine. Instead of directly converting photons to electricity, the system converts optical energy to thermal energy, then to mechanical work, and finally to electrical power. This substitution enables utilization of longer wavelength laser radiation (including CO2 laser at 10.6 micrometers) that semiconductor materials cannot efficiently convert.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Power

If highly concentrated laser light is absorbed directly by air to cause molecular disassociation and increase pressure, then laser-powered propulsion is achieved, but the process is inefficient and requires very high laser power density

Engineering Contradiction:

Improvelaser power densityVSAvoidenergy absorption efficiency

Core Design Contradiction:

PowerVSLoss of energy

Solution Approach 1:

The patent introduces an optical absorber as an intermediary substance between the laser beam and the air. The optical absorber efficiently captures laser energy and transfers it as thermal energy to the air, causing controlled heating and expansion. This intermediary approach dramatically improves energy transfer efficiency compared to direct air absorption, reducing the required laser power density while maintaining effective propulsion.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Productivity

If dedicated working fluids are carried by the vehicle for laser-powered heat engines, then efficient energy conversion is achieved, but the vehicle requires periodic replenishment of consumable fluids

Engineering Contradiction:

Improveenergy conversion efficiencyVSAvoidworking fluid consumption

Core Design Contradiction:

ProductivityVSLoss of substance

Solution Approach 1:

The patent makes the heat engine system self-sufficient by using ambient air as the working fluid. The air intake system continuously supplies fresh air to the optical absorber, eliminating the need to carry consumable working fluids. The system converts optical energy to thermal energy in the air, then uses the heated air expansion to drive the heat engine, creating a closed-loop process that only requires ambient air intake and exhaust.

Inventive Principle:

Principle #25Self-service

4Quantity of substance

If ambient air is used as working fluid with direct laser absorption, then no consumable fluids are needed, but the absorption is too low requiring very high laser power density

Engineering Contradiction:

Improveworking fluid availabilityVSAvoidlaser power density requirement

Core Design Contradiction:

Quantity of substanceVSPower

Solution Approach 1:

The patent introduces an optical absorber material as an intermediary with high absorption coefficients for laser wavelengths. This absorber captures laser energy efficiently and transfers it as heat to the ambient air flowing through the system. The intermediary absorber enables effective utilization of ambient air as working fluid without requiring prohibitively high laser power densities, as the absorber concentrates and transfers energy to the air in a controlled manner.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 approach provides reliable and efficient power to UAVs, overcoming wavelength and power density limitations, improving engine efficiency, and eliminating the need for consumable fluids, while simplifying control systems by direct optical power delivery.

Implementation Method 1

devices for absorbing laser optical radiation, converting the light into heat

Methodology Applied

Scientific EffectAbsorption of optical radiation: Absorption (EM radiation)

Implementation Method 2

harvesting mechanical work from expanding working fluid in the heat engine

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS9920706B1Methods of laser powering unmanned aerial vehicles with heat engines

Publication Date: 2018.03.20 YAVID DMITRIY MR

AI summary

Methods of laser powering unmanned aerial vehicles (UAV) with heat engines are disclosed. The laser powered heat engines are used in conjunction with devices for absorbing laser optical radiation, turning the laser optical radiation into heat, supplying the heat to a working fluid of the heat engine and harvesting mechanical work from expanding working fluid in the heat engine.