Efficient Optical Shear-Stress Sensors with High Temperature Ranges

Directly Quantifies Skin Friction Drag in High-Temperature Environments

This device uses sensors to accurately and quickly process wall shear-stress in applications for the aircraft industry. The measurement of skin friction drag is vitally important to the aircraft industry, and skin friction drag causes an estimated 50 percent of the total vehicle drag for a typical transport aircraft. The macro-scale measurement systems that are widely in use cannot sufficiently meet the demands for directly obtaining accurate shear stress data. And while optical-MEMS-based laser-Doppler anemometers have shown promise, they lack the ability to generate small measurement volumes in high numbers.

Researchers at the University of Florida have created a floating-element shear stress sensor that allows direct, high temperature measurements of skin friction. This device allows for quick, accurate quantitative measurements and covers high-ranging temperatures, providing advantages in efficiency, applicability, and functionality when compared to available shear-stress sensing systems.

Application

A sensing system that accurately and quickly processes wall shear-stress in aircraft industry applications

Advantages

• Delivers quantitative, easily measurable results, providing a unique competitive advantage over existing devices
• Provides data in environments exceeding temperature ranges of competing products, increasing sensor efficiency and applicability
• Reverses and separates flows, allowing the sensor to detect the direction of the flow to yield greater accuracy
• Uses materials that can transmit, absorb, or reflect optical signals, maintaining sensor interoperability with sensors of the same type
• Utilizes high-temperature materials, such as sapphire, allowing the device to function upon distant placement for various temperature-sensitive electronics

Technology

This sensing system uses floating-element shear stress sensors that enable the direct, high temperature measurement of skin friction based on geometric and/or interferometric optical techniques. Since they use materials able to transmit, absorb, or reflect optical signals, the sensors maintain functionality at higher temperatures. Additionally, the use of high-temperature materials such as sapphire allows use of the sensing system at a distance for various temperature-sensitive electronics.