The Application Ofwireless Sensor Network And The Coupled Heat And Moisture Field Simulation In Grain Monitoring

According to the data of the State Administration of Grain, more than100billion kilograms of post-harvest grain have been lostannually, accounting for more than9%of the nation’s grain production.Grain storage and transportation sectors lost about10billion kilograms. Therefore, in order to effectively reduce food losses during storage, monitoring the grain situation has been widely concerned. This paper developed a wireless monitoring system for grain monitor system and its main results are as follows:(1) For medium and large barn, we designed a wireless network monitor system which takes the cost and performance into account:Wireless sensor nodes are arranged in the upper of the grain bulk, so it can monitor multiple points of grain parameters in the vertical space beneath; routing nodes are equipped with caching and self-networking features in order to ensure security; gateway nodes are provided with GPRS data which can upload and cache. The whole system has multiple data protection mechanism to ensure the stability of the system.(2) For common wireless Grain Systems Research Institute, using2.4GHz technology has some disadvantages:the transmission distance, lack of stability and anti-jamming performance.This paper introduced470MHz-510MHz wireless ad hoc networks grain monitoring technology which is widely used in industry, into the barn for the first time. On the one hand,solve the problem of signal stability, on the other hand it also bypasses the2.4GHz technical barriers from abroad.(3) Using SHT11to monitoring temperature and humidity at the same time inside the food bulk, as well as to solve the problem of harsh environment’s negative impact on sensors, we use special protective measures to protect sensors against long-term pollution.(4) Study theinternal heat and mass transfer phenomena of grain under natural convection conditions. Established numerical simulation software models to simulate the variation of temperature and humidity and compare the results with the monitoring system. It shows that the numerical simulation results are in accordance with granary internal variation generally.It has some reference value, but the model still need further improvement and the parameters should be optimized.)...