Design Of Wireless Monitoring System For Dangerous Gas And Study On Gas Source Localization Algorithm

Dangerous gas often appears in people’s daily production and lives. The gas’s leakage may cause terrible harm, such as residential natural gas, industrial gas for industrial use, toxic gas following with natural disaster or safety accident and so on. Meanwhile, if the monitored area is a large area, it is often difficult to locate the position of the gas source after the gas leakage. For the above reasons, this paper designed a monitoring system for hazardous gas based on wireless sensor networks, and then studied the gas source localization algorithm.In order to monitor the gas leak and locate the position of the gas source, this paper designed a monitoring system for hazardous gas based on ZigBee wireless sensor technology. The system was mainly divided into lower computer system for monitoring nodes and computer remote monitoring platform. The lower computer monitoring nodes were mainly divided into gas monitoring fixed nodes, gas monitoring mobile nodes, router nodes and coordinator nodes. The gas monitoring fixed nodes were mounted in fixed position to monitor gas concentration. The gas monitoring mobile nodes were equipped with robots or professional staffs to monitor gas concentration for free movement and eliminate dangerous case. Fixed or mobile gas monitoring nodes sent gas concentration detected out through the ZigBee network. The routers were mainly responsible for information relay and information transfer to expand the scope of monitoring system. At the same time some routers provided their own routing node ID for gas monitoring nodes nearby, so that the gas monitoring nodes could judge the routing area according to the routing ID from the routers. The coordinator nodes collected data from gas monitoring nodes and uploaded the data to the host computer monitoring platform. At last the computer remote monitoring platform based on C# classified, processed the data, displayed the gas concentration of each node by region, and drew history graph of each node’s gas concentration.To be able to locate the gas source after gas leakage, this paper studied the gas source localization algorithm. Firstly this paper analyzed some different gas source localization methods, and selected a kind of method based on the model of locating gas source. Then, this paper described the different gas diffusion models, was focused on the Gaussian plume models, and simulated Gaussian plume model for different height planes, different atmospheric stability, different gas leak sources and wind conditions, which could be directly applied in the model location algorithm. Finally, according to the method of least squares search method, this paper divided the area to be measured into a plurality of grid regions, and searched the region whose sum of square of the difference between actual outputs with the model outputs was the smallest. The searched region was further divided and searched until finding the gas source location that met the requirements. According to the simulation results, this method of gas source locating met the demand of gas source localization.