密度可以解释熔融金属的性质和行为, 密度的变化特征反映了熔融金属内部原子距离和配位数等的基本变化。研制了一种测量熔融金属密度的浮子式光纤Bragg光栅传感器, 浸没在熔融金属中的浮子受浮力作用, 通过传递杆、等臂杠杆及连杆, 拉动等强度悬臂梁产生扰度变化, 根据检测粘贴在等强度悬臂梁表面的光纤Bragg光栅中心波长移位值, 测出浮力值, 进而检测熔融金属密度。该传感器的理论灵敏度为0.115 pm/(kg/m3), 4次实验得到熔融金属的平均密度为7.574×103 kg/m3, 略小于理论密度7.621×103kg/m3, 相对误差为0.62, 均方根误差为117.371kg/m3。

The quality and behavior of the molten metal can be defined by density, which is reflected the basic changes of the inter-atomic distance and coordination number of molten metal. A float-type fiber Bragg grating sensor is manufactured to measure the density of molten metal. The floater submerged in molten metal is controlled by buoyancy force. Through the driving rod, equal armed lever and connecting rod, pulling the equal strength cantilever beam, the deflection is changed. On the basis of detecting the wavelength shift of fiber Bragg grating which is pasted on the surface of cantilever beam the buoyancy values be obtained. The density of molten metal is detected. The theoretical sensitivity of the sensor is 0.115pm/(kg/m3). According to the four times experiment, the average density value of the molten metal is 7.574×103 kg/m3, which is less than the theoretical data for 7.621×103 kg/m3. The relative error is 0.62, the root mean square error is 117.371 kg/m3.