Design And Implementation Of Wireless Monitoring System For High Temperature Point In Goaf

In recent years,with the widespread application and promotion of fully mechanized top coal caving technology in coal mining,fires in coal mine goaf have become a major safety hazard threatening coal mine production.The occurrence of fires in mined-out areas of coal mines is likely to cause problems such as waste of resources,environmental pollution,production stagnation,and even casualties,which seriously affect production efficiency and social stability.Due to the complex spontaneous combustion mechanism of coal mine goaf,the randomness and difference of spontaneous combustion occurrence,and the internal environment cannot be obtained by direct means,it is impossible to detect the high temperature point changes in the coal mine goaf and accurately locate it before the fire takes shape.The prevention and control measures are blind and lagging,resulting in frequent fire accidents in the coal mined-out area and threatening the safety of coal mine production.In view of the above problems,this paper first discusses the channel frequency selection and effective communication distance in the coal cover environment of the coal mine goaf.Through the theoretical analysis of electromagnetic waves and the construction of the porous medium model,the propagation and attenuation characteristics of electromagnetic waves in the coal cover environment of the coal mine goaf is explored.The communication channel frequency and node spacing of the high-temperature point monitoring system of the coal mine goaf are determined.Secondly,a polling mandatory data collection strategy is designed.By studying the energy consumption types and network protocols of wireless sensor networks,a route model energy consumption model applied to wireless monitoring of high temperature points in coal mine goaf is established.At the same time,the existing routing protocol and data dissemination process is improved,reduce the packet loss rate and failure rate in the dissemination,and improve the overall stability and energy saving of the wireless monitoring system of the high temperature point of the coal mine goaf.Based on the above design research,design and process impact-resistant flame retardant shell,low power circuit and simple host computer interface,using MSP430 low power chip as the main control,DS18B20 digital chip as the sensor,SX1278 wireless module as the transceiver,Completed the design and processing of the monitoring node circuit;used PTFE as the impact-resistant flame-retardant shell material;used LabVIEW to write the host computer program;and used the serial port to network port module to complete the circuit design and processing of the convergence node.Finally,the reliability and communication performance of the monitoring system are fully tested.The test results show that the system can work at a temperature of 0 ?-80 ?,withstand impact of 30 g,the temperature test accuracy is ± 0.5 ?,the working standby time is about 33 days,which can meet the actual requirements of high temperature point monitoring of coal mine goaf.Through the field test,the communication performance of the system was further tested,and the multi-hop performance of the system network and the transmission performance under the condition of soil burial were verified.The test results showed that the wireless monitoring system for the high temperature point of the coal mine goaf can complete the Long-term stable monitoring of high temperature points in empty areas.