Structural Design of Ocean Temperature and Depth Sensor with Quick Response and High Sensitivity

Area of Science:

• Oceanography
• Sensor Technology
• Materials Science

Background:

• Traditional Expendable Bathythermographs (XBTs) suffer from low sensitivity and slow response times.
• The complex marine environment poses challenges for accurate depth measurements using empirical time-depth formulas.

Purpose of the Study:

• To design and develop a novel ocean temperature and depth sensor.
• To overcome the limitations of existing XBTs in terms of sensitivity, response time, and accuracy in marine environments.

Main Methods:

• Designed a sensor utilizing a brass diaphragm and liquid filling.
• Compared Fiber Bragg Gratings (FBGs) with varying lengths and different liquid materials for heat transfer time.
• Analyzed brass diaphragms of different radii and thicknesses for optimal elastic properties.
• Investigated the impact of inner metal shell section radius on temperature and depth sensitivity.

Main Results:

• Achieved a fast response time of 51 ms using GaInSn liquid for temperature sensing.
• Selected brass diaphragms with 10 mm radius and 1 mm thickness, maintaining elasticity up to 5 MPa.
• Optimized sensor configuration yielded a temperature sensitivity of 1.065 nm/°C and pressure sensitivity of 1.245 nm/MPa.
• Demonstrated close response times for both temperature and depth measurements.

Conclusions:

• The developed sensor offers improved data accuracy compared to traditional XBTs.
• Tunable sensitivity through internal metal shell adjustments meets diverse oceanographic data detection needs.
• The sensor provides high sensitivity and fast response times for ocean temperature and depth monitoring.