超声导波温度传感器是目前工业领域中新兴的测温仪表,其导波的选取对传感器的测温性能有着重要的影响。 磁致伸 缩扭转波具有易于产生与拾取、衰减小的特点,且其波速随温度呈线性关系,适合应用于超声导波温度传感器的设计。 本文选 用磁致伸缩材料 Fe83Ga17 丝产生和传导磁致伸缩扭转波,通过固定距离内扭转波的飞行时间与温度的关系,计算扭转波的波速 与温度的拟合关系,根据该拟合关系与实测扭转波波速实现温度测量,并提出了基于磁致伸缩扭转波温度传感器的输出电压模 型。 实验可得,在室温~500℃下,磁致伸缩温度传感器的输出电压幅值达到 215. 7 ~ 465. 2 mV,与本文提出的输出电压模型一 致,能够满足一定温度范围内的测温要求。 为提高温度传感器的测温上限,将 Fe83Ga17 丝与热敏材料 Ni 20Cr80 丝耦合成新的波 导丝,得到了结构优化后的温度传感器。 在室温~1 200℃温度区间内,传感器能够输出幅值范围为 44. 9~ 85. 6 mV 的输出电压 信号,温度与扭转波波速的拟合关系始终保持高度线性,有能力实现 1 200℃以下的可靠测温。
The ultrasonic guided wave temperature sensor is currently an emerging temperature measuring instrument in the industrial field, and the selection of its guided wave has important impact on the performance of the sensor. Magnetostrictive torsional wave is suitable for the application, as the basis for temperature measurement with its wave speed proportional to the temperature as well as the characteristics of low decay and easily pick-up. In this article, the magnetostrictive material Fe83Ga17 wire is selected to generate and conduct magnetostrictive torsional waves. The relationship between the flight time and temperature of the torsional wave at a fixed distance is calculated to achieve the fitting relationship between the wave velocity and temperature. According to the fitting relationship and the measured torsional wave velocity, the temperature measurement is realized, and an output voltage model based on a magnetostrictive torsional wave temperature sensor is proposed. In experiments, the output voltage of the magnetostrictive temperature sensor reaches 215. 7~ 465. 2 mV under the room temperature up to 500℃ . The fitting relationship between the measured temperature and the wave velocity can be used as a basis for temperature measurement. To increase the upper temperature measurement limit of the temperature sensor, Fe83Ga17 wire is coupled with the heat sensitive material Ni 20Cr80 wire into a new waveguide wire, and the temperature sensor after structural optimization is obtained. The unamplified output voltage of the optimized sensor reaches 44. 9~85. 6 mV under the temperature from room temperature up to 1 200℃ . The wave speed of the torsion wave remains highly proportional to the temperature in the temperature region, which is capable for reliable temperature measurement under 1 200℃ .