| The swine breeding environment directly affects the health and production capacity of pigs.But at present,there is no substantive and effective measures in controlling the indoor environment of breeding places in china,and it also has not attracted much attention of the poultry feeders.These cause many problems to the breeding environment.Based on the fieldwork and measuring data,a 3D model of 1:1 was build for simulating,analyzing and evaluating the internal environment of fattening pig house by using ANSYS Fluent software.In order to solve the problems of temperature and velocity field of pig house,a reasonable optimization scheme was proposed and a new model was established.The results are as follows:1.A target pig house was selected for data measurement based on the field investigation,then a simulated 3D model was built.The comparison between the value of simulation and actuality indicates that there is little difference between the measured and simulated temperature,which follows the similar rules.The maximum absolute error of the measured and simulated temperature is 1.52 ℃,and the maximum relative error is about 5.9%.At the same time,the absolute error range of the measured and simulated values of wind speed is 0 m/s ~0.19m/s,and the relative error is less than 15%.The results prove that the simulated values are quite in accord with the measured values,and it is feasible to simulate the flow field in pig houses by using FLUENT software.2.According to the simulation results,the environment of pig house was analyzed and the following problems were discovered in piggery environment.The temperature of pigs activity area is basically maintained at 26℃~27℃ in summer,which beyond the optimum temperature for growing-finishing pigs.The wind speed is below 0.2m/s in most areas,and the areas less than 0.3m above the ground exist stagnant zones.At the same time,the nearer the ground is,the greater the area of stagnant zone is.Because the air has trouble moving,the heat and humidity dissipation of pig body is greatly reduced.3.Three reasonable optimization schemes were designed in order to solve the environment problems of the target pig house,and then three 3D models were established and simulated.Optimization scheme 1 changed the side air supply of the original scheme to top air supply model.Optimization scheme 2 arranged the outlet below the slatted floor based on scheme 1.Optimization scheme 3 retained the original side air supply mode,and the outlet mode was the same as the scheme 2.The simulation results of the three optimization schemes were analyzed,and the results shows that,scheme 1 and 2 can effectively improve the problem of low wind speed at pig activity area,and temperature decreased with the increasing of wind speed in the house.But because of the different settings of the outlet,the temperature and velocity field of the scheme 2 are more well-distributed and the improvement of the indoor environment is also the best.Optimization scheme 3 also can improve the problems existed in the original plan by the improvement on outlet mode,but the effect is not as good as scheme 1 and 2.This study proves that CFD technology is an effective tool for the simulation of piggery environment.It not only provides an economical and effective method for the study of piggery environment,but also provids a theoretical basis and guidance for the design and optimization of the ventilation system. |
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