High-speed phosphor thermometry

Area of Science:

• Materials Science
• Optical Diagnostics
• Thermodynamics

Background:

• Phosphor thermometry measures surface temperature using luminescence from doped ceramics.
• Existing systems using Q-switched lasers (10 Hz) are limited to time scales >100 ms.
• This limits application in rapidly changing thermal environments.

Purpose of the Study:

• To develop and demonstrate a high-speed phosphor thermometry system.
• To enable temperature measurements at millisecond or faster timescales.
• To characterize a new phosphor material for high-repetition rate applications.

Main Methods:

• Employed a highly repetitive laser system (kHz regime) for phosphor excitation.
• Utilized a fast-decaying phosphor material.
• Characterized phosphor temperature-lifetime properties and measurement precision.
• Investigated laser power effects on phosphor coatings.
• Demonstrated the system in an optically accessible internal combustion engine.

Main Results:

• Achieved a 6 kHz measurement repetition rate (1 sample/crank angle degree at 1000 rpm).
• Successfully measured temperatures in a highly transient internal combustion engine environment.
• Characterized material properties and validated measurement precision.

Conclusions:

• The developed high-speed phosphor thermometry system overcomes previous temporal limitations.
• This technique is suitable for analyzing rapid temperature changes in dynamic systems.
• The system offers a novel diagnostic tool for internal combustion engine research and other transient thermal applications.