Mathematical Simulation Of The Contact Type Fiber Liquid Level Sensor And Its Pollution

The sensor head of fusion fiber-optic single-point liquid-level sensor is investigated experimentally and theoretically in this paper, which is sensitive to the refractive index of surrounding media. The sensor head's operation principle and optical characteristic of this type sensor is analyzed. The mathematic model of the sensor is established. The simulation software of ray-tracing is developed in VC++ language. Theoretical calculations accord with experimental results basically, verifying the rationalities of the mathematic model. The model can supply the fabrication of the tips with effective references. It is found that the fusion sensor head in the ratio of one point two to one has the maximum optical modulation depth-20dB.The contamination mechanism of the sensor head has been studied for increasing the operating life time of the sensor system. Two different working medium, oil and water, is tested respectively. The method that can improve resistance to pollution by coating technique of liquid phase deposition TiO2 film on the surface of the fiber tip is tested. The experimental results in the water indicate that the anti-pollution capacity of the coated fiber sensor head is much better than uncoated one.