Optimised Chirped Fibre Bragg Gratings for Detonation Velocity Measurements

Area of Science:

• Optics and Photonics
• Combustion Science
• Materials Science

Background:

• Chirped fibre Bragg gratings (CFBGs) are increasingly utilized in detonation velocity experiments.
• Understanding the impact of CFBG design parameters on measurement linearity is crucial for accurate detonation studies.

Purpose of the Study:

• To investigate how CFBG design parameters (chirp-rate, reflectivity, apodisation) influence linearity in detonation velocity measurements.
• To identify optimal CFBG configurations for enhanced detonation velocity probing.

Main Methods:

• Experimental analysis of CFBG performance under detonation conditions.
• Systematic variation of CFBG chirp-rate, reflectivity, and apodisation.
• Measurement of detonation velocity using optimized CFBG probes.

Main Results:

• High chirp-rate, low reflectivity, and absence of apodisation were found to be optimal CFBG design parameters for linear detonation velocity measurements.
• A 24 cm optimized CFBG was successfully used to measure detonation velocity, representing the longest test of its kind.
• Demonstrated significant improvements in measurement linearity with optimized CFBG configurations.

Conclusions:

• The study provides clear guidelines for designing optimal CFBG detonation velocity probes.
• Optimized CFBGs offer a promising approach for accurate and linear detonation velocity measurements.
• The findings contribute to advancing diagnostic techniques in high-speed combustion research.