Diode laser-based air mass flux sensor for subsonic aeropropulsion inlets

Area of Science:

• Aerospace Engineering
• Optical Sensing Technologies
• Combustion Science

Background:

• Accurate measurement of air mass flux is critical for gas turbine engine efficiency and control.
• Existing methods may lack the precision or real-time capability required for advanced engine diagnostics.
• Optical sensing offers a non-intrusive approach to in-situ measurements.

Purpose of the Study:

• To evaluate the performance of a new diode-laser-based optical air mass flux sensor.
• To assess the sensor's accuracy and precision across a range of gas turbine engine operating conditions.
• To compare data-reduction strategies for optimizing sensor performance in flight applications.

Main Methods:

• Development of a fiber-coupled, room-temperature diode laser sensor system.
• Simultaneous measurement of O(2) density and Doppler-shifted velocity.
• In-situ testing on a full-scale gas turbine engine from idle to full afterburner.

Main Results:

• The sensor demonstrated high accuracy and precision, achieving 1-2% of full scale for density, velocity, and mass flux.
• Achieved a precision-limited velocity measurement as low as 40 cm/s at atmospheric pressure.
• Quantitatively compared various data-reduction procedures for optimal sensor data processing.

Conclusions:

• The optical air mass flux sensor is a viable technology for precise, real-time measurements in gas turbine engines.
• The sensor's performance is robust across a wide range of engine power levels.
• Identified optimal data-reduction strategies for potential flight sensor packages, enhancing engine monitoring and control.