Light Scattering Aerosol Monitoring For Fire Evacuation

Fire is a major disaster threatening people’s lives and property.Realizing early fire warning can reduce fire hazards and buy precious time for fire evacuation.At present,domestic fire and fire early warning are mainly realized through specific smoke detectors and video image monitoring.They have rapid early warning capabilities in specific occasions,but they have a small range of adaptation,low flexibility and high costs.Therefore,it is imperative to design a more flexible and stable fire monitoring system.Based on the characteristics of smoke and aerosols in the early stage of a fire,the paper studies laser measurement and flow measurement technology,and designs and implements a light scattering aerosol monitoring system for fire evacuation.The hardware platform of the system collected aerosol wind speed,temperature and concentration data,and transmitted the data to the control terminal for calibration and processing,and completed the comparative verification of various model fitting methods.The software side of the system realizes the corresponding data recording,display,analysis and early warning functions.The system has a faster response speed,higher flexibility and lower cost,and has a variety of working modes at the same time,which can complete active or passive monitoring according to different environments and requirements.The work done in the paper is as follows:(1)According to the composition and formation principle of aerosol,analyze the indoor aerosol particle monitoring method,and select the method of laser measurement combined with flow measurement.Based on the characteristics of indoor aerosol particles and the principle of scattering,a specific design plan for collecting aerosol data by light scattering is obtained.Completed the optical tracking simulation and the design and realization of the laser cavity structure.Using the constant temperature measurement method,a mathematical model of aerosol flow is established.(2)According to the selected concentration light scattering measurement method and flow constant temperature measurement method,the hardware construction of the monitoring system is completed.In order to enhance the stability and sensitivity of the hardware platform,amplifying,filtering and feedback circuits have been added,and each module circuit has been designed and improved.The physical circuit board was produced,and the test and calibration were completed.(3)Based on the established mathematical models of flow and concentration,the embedded software and control terminal software were designed and implemented,and the measured data were analyzed.The software system receives the concentration,wind speed and temperature data from the hardware side,completes data processing tasks such as noise reduction,fitting,and calibration,and records the working mode,power state and laser working state.Finally,these data and status are visualized and transformed into intuitive working conditions,aerosol concentrations,and related analysis charts.The light scattering aerosol monitoring system for fire evacuation achieves the expected results in the test.It ensures the reliability and flexibility while monitoring aerosol at a high reaction rate,and has a wide application prospect.