Research On Optical Methods To Measure Flux And Concentration Of Water Mist Field

With the development of science and society,the nozzle atomization technology is increasingly used in fire protection,agriculture,industry and aerospace.It is of great significance to accurately measure the mist field’s parameters.The mist field has dynamic characteristics,so it is not suitable for contact measurement.Mechanical method or electrical method is used for collection and measurement,such as test tube collection method and other simple methods.Generally,the measuring cup method or weighing method is used to measure the concentration distribution of mist field.However,it is difficult to realize online real-time measurement by these methods,which brings great difficulties to the mist mistfield research.To effectively solve the difficult problem of on-line real-time measurement of mist field’s flow and concentration distribution,the optical path is built by using the refraction of geometrical optics and the scattering of spectroscopy.The photoelectric signal is respectively collected by photoelectric coupling and image devices.The signal is processed in real time.A prototype for measuring the flow distribution of mist field is developed.The concentration distribution experiment is completed,and the image processing method is studied.The experimental results of flow rate distribution and concentration distribution in the mist field are analyzed,and the expected results of the experiment are obtained.The main work is as follows:1.According to the optical refraction law,a liquid level-time difference method for measuring the mist field flow distribution is proposed.Photoelectric sensors are arranged at the same height of the transparent sampling tube array.The time when the water flow fills the sampling tube is independently collected.The collection time is converted into instantaneous flow value to realize the measurement of mist field flow distribution.2.A test platform for flow distribution of mist field is developed.The acquisition and motion mechanism of the test platform is designed and processed,and the data acquisition hardware scheme is established by using the array photocoupler as the light source and sensor.By using 32-bit microcomputer,the photoelectric acquisition and motion control circuit board are developed.3.The prototype was used to carry out mist field flow distribution experiments.The results of different nozzles types were visually displayed and analyzed.The feasible results are obtained.4.Based on the scattering principle,the experiment of mist field concentration distribution is carried out by using monochromatic light source and image acquisition system.The calculation results of mist field concentration processed by digital image method and the results measured by the prototype are analyzed.By comparing the experimental results of flow distribution and concentration distribution of mist field,the actual effect of the measurement method is verified.