光加热光纤光栅阵列液位测量方法研究OA北大核心CSTPCD

A safe and reliable level meter is an indispensable device in modern industry.A liquid level measurement method based on optical heating and optical fiber grating array is proposed.The principle is that a laser heats the cobalt-doped optical fiber,controls the temperature field of the fiber,and the grating array is used to measure the temperature field distribution.Due to the difference of gas-liquid thermal conductivity,the temperature at the gas-liquid interface changes abruptly,so as to realize the determination of the liquid level.In the experiment,the cobalt-doped optical fiber and the dense grating array are tightly fixed together,and the temperature change is atten-uated as an exponential function along the direction of light propagation when 1.5 W high power pumped light is input into the cobalt-doped optical fiber with attenuation coefficients of 0.71dB/cm and 0.28dB/cm,respectively.The accuracy and range of liquid level meas-urement mainly depend on the pump light power and the absorption coefficient of cobalt doped optical fiber.After comparison,0.28 dB/cm cobalt doped optical fiber is finally selected as the heating optical fiber for liquid level experiment.The temperature field distributions at different liquid levels are measured.The experiment proves that it is feasible to measure the liquid level by measuring the temperature dis-tribution.The error is 2 mm within the range of 0-88 mm.The experiments show that the proposed sensing system is simple in structure and low in cost,and has potential applications in liquid level measurement.