Research On Reflective Optical Fiber Detection Technology Of Oil Contamination Degree

Oil contamination is one of the main reasons for mechanical equipment failure and reduced working life.In view of the fact that 70% of hydraulic equipment failures are caused by oil contamination and solid particles are the main contaminations,and most of the commonly used oil contamination detection technology equipment has complex structure,expensive and inconvenient online detection status,a reflective type is proposed.The principle of optical fiber oil contamination detection and the design of corresponding optical fiber sensors.The following are the main tasks completed:(1)The working principle of the reflective optical fiber detection sensor for oil contamination degree is analyzed.According to the working principle of the reflective optical fiber sensor,combined with the light intensity attenuation caused by the blocking of light by oil contamination particles,the working principle of the reflective optical fiber oil contamination degree detection sensor is proposed.Therefore,based on the assumption of the optical field distribution,the fiber end optical field distribution model of the reflective optical fiber oil contamination degree detection sensor was established,and the shadow ratio of the contaminated oil particles in the optical field and the influence factors of the light intensity change were established.The modulation function of the relationship between the degree of oil contamination and the received light intensity.(2)The mathematical model of the reflective optical fiber detection sensor for oil contamination degree was established.According to the working principle of the reflective optical fiber sensor,combined with the light intensity attenuation caused by the blocking of light by the oil contamination particles,the mathematical models of the output characteristics of the reflective optical fiber detection sensor with single emission and single reception and single emission and dual reception are established respectively.(3)The output characteristic simulation of the Reflective optical fiber oil contamination degree detection sensor was carried out,the sensor parameters were determined,and the structural design of the sensor was completed.Through simulation analysis,the function curve between sensor output and contamination concentration under different conditions is obtained.According to the simulation results,it is determined to adopt the double-loop coaxial optical fiber layout,and the numerical aperture,core diameter,reflection distance and other parameters of the optical fiber sensor are determined.On this basis,the sensor structure design is completed.(4)The conditioning circuit and signal acquisition program of the reflective optical fiber detection sensor for oil contamination degree are designed.Analyze the principle of photoelectric conversion and signal amplification,and design the sensor conditioning circuit.So,the design of the signal acquisition program is completed by Labview.(5)The construction of the experimental platform and the calibration experiment of the reflective optical fiber detection sensor for contaminated oil degree have been completed.According to the contamination level standard,oil samples of different contamination levels were manually prepared,the experimental plan of the sensor characteristic experiment was designed,and the corresponding experimental platform was built to calibrate the Reflective optical fiber oil contamination degree detection sensor.Experimental results show that,As the concentration of contaminated particles in the contaminated hydraulic oil increases,the sensor’s received light power gradually decreases.The reflective optical fiber oil contamination degree detection sensor designed in this paper can realize the detection of hydraulic contamination oil with different contamination degree standards.