Study On Temperature And Thermal Environment Monitoring And CFD Model Of Pig House With Longitudinal Ventilation Based On WSN

In today's society,pork has become the daily needs of people,and the pig industry has gradually become a pillar industry in China.Therefore,pig health problems in the process of pig breeding have become the focus of attention of pig farms.The influence of pig house thermal environment on pig health is particularly obvious,so how to effectively obtain and analyze the thermal environment of pig house is particularly important,and a set of wireless sensor network needs to be developed to replace human measurement,which can not only monitor in real time,but also do not need people to enter the pig house,which can reduce the harm of harmful gases to human body.In this study,the thermal environment of the common longitudinal ventilation pig house was monitored,and combined with the relatively mature CFD simulation technology,the thermal environment change of the pig house was simulated and analyzed.The analysis results are of great significance for the research on the distribution law of the thermal environment in the pig house and the control of the pig house in the later stage.There are many factors that affect the thermal comfort of pig house,including wind speed and thermal radiation in addition to temperature and humidity.The thermal comfort of pig body is the result of the comprehensive action of these factors.The traditional temperature and humidity index can not express the real thermal comfort of pig body.In this paper,based on the human PMV(average prediction vote)index,the corresponding pig PMV index is proposed.At the same time,a thermal environment monitoring system based on wireless sensor network is designed.The multi-point simultaneous measurement of pig house is realized through wireless network,and the thermal environment of pig house is monitored continuously for three days.The experimental site is a typical longitudinal ventilation pig house in Central China.The wireless sensor nodes are evenly distributed according to the plan of the pig house.The measured data at a certain time of the day under the action of wet curtain are selected for CFD simulation to verify the thermal environment of the pig house under the action of wet curtain,and the PMV index of pig body is used to evaluate the thermal environment of the pig house.Computational fluid dynamics(CFD)was used to establish a credible temperature and humidity model field for pig house under the action of wet curtain in summer.On this basis,the PMV field simulation model of pig body was calculated.Compared with the data of wireless sensor network,the error fluctuation of the model was less than 6%.The simulation results show that the temperature of pig house under the action of wet curtain is reduced by about 4 ?,and the air flow presents high and medium low on both sides.There is a certain area of airflow dead zone near the wall and the corner of pig house.The fluctuation range of PMV index of pig body under the action of wet curtain is between-0.5 + 0.5,which belongs to the comfortable index range.Through this study,we can better understand the distribution of thermal comfort in pig living areas,and provide a solid foundation for optimizing the living environment of pigs in the future.