Reflection Control Layer for Mobile Body Air Resistance
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Solution Overview
Problem
Existing methods for reducing air resistance in mobile bodies, such as railway vehicles, are ineffective in utilizing infrared radiation and oxygen absorbing regions, leading to low reflectance and increased air temperature near the vehicle, which hampers the reduction of air resistance.
Innovation Solution
A reflection control layer is formed on the surface of the mobile body, with a refractive index outside the range of the body-side substance and air, and a thickness between 187.5 nanometers and 275,000 nanometers divided by the refractive index, to reflect light in the wavelength region from 0.75 micrometers to 100 micrometers, thereby heating the air and reducing air resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a conventional reflection control method (increasing reflectance in 0.78-2.1 micrometer range) is used, then near-infrared ray reflection performance is improved, but reflectance remains low in the infrared radiation region (>=2.5 micrometers) and oxygen absorbing region (0.75-0.78 micrometer)
Solution Approach 1:
The patent changes the optical parameters of the reflection control layer by selecting materials with refractive indices outside the range between the body-side substance and air, and by controlling the layer thickness within a specific range (187.5/n to 275,000/n nanometers). This enables the layer to reflect light across a broad spectrum including the infrared radiation region (>=2.5 micrometers) and oxygen absorbing region (0.75-0.78 micrometer), resolving the limitation of conventional methods that only addressed the near-infrared range.
2Temperature
If the air temperature in the mainstream is not increased, then the air resistance of the mobile body remains high, but increasing the temperature requires effective utilization of infrared radiation which has low reflectance
Solution Approach 1:
The patent modifies the optical parameters of the reflection control layer to achieve high reflectance in the infrared radiation region (wavelength >= 2.5 micrometers) and oxygen absorbing region (0.75-0.78 micrometer). By selecting materials with refractive indices outside the range between the body-side substance and air, and controlling the layer thickness within 187.5/n to 275,000/n nanometers, the system can effectively reflect infrared radiation to heat the mainstream air, thereby reducing air resistance.
3Temperature
If the reflectance in the infrared radiation region is increased, then the air temperature in the mainstream can be increased to reduce air resistance, but the refractive index and thickness parameters must be precisely controlled
Solution Approach 1:
The patent specifies precise parameter ranges for the reflection control layer: refractive index must be outside the range between the body-side substance and air, and thickness must be between 187.5/n and 275,000/n nanometers (where n is the refractive index). These controlled parameters enable the layer to reflect infrared radiation effectively, heating the mainstream air to reduce air resistance.
Solution Approach 2:
The patent employs composite material structures where the reflection control layer is formed on the surface of the mobile body. This composite structure combines the base material with a specialized reflection layer having specific optical properties, enabling broad-spectrum infrared reflection while maintaining structural integrity and functional performance.
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 solution effectively reduces air resistance by heating the air in the mainstream, leading to a density reduction of approximately 2%, resulting in a significant decrease in air resistance and improved fuel efficiency.
Implementation Method 1
a reflection control layer is formed on a surface of the mobile body... to reflect light in the wavelength region from 0.75 micrometers to 100 micrometers, thereby heating the air
Implementation Method 2
heating the air in a mainstream by light reflected on the surface of the mobile body
Data Source
AI summary
A mobile body has a reflection control layer that reflects light in a wavelength region of sunlight or in a wavelength region of infrared radiation formed on a surface thereof. A mainstream outside the mobile body is heated by the reflected light to reduce air resistance of the mobile body. A refractive index of the reflection control layer is a value outside a range between a refractive index of a body-side substance and a refractive index of air. A thickness of the reflection control layer is equal to or larger than a value obtained by dividing 187.5 nanometers by a refractive index of the reflection control layer, and equal to or smaller than a value obtained by dividing 275,000 nanometers by a refractive index of the reflection control layer.