| China is the world’s largest egg breeding consumer.Since the 1980 s,China has gradually changed from the traditional free-range breeding mode to the modern intensive breeding mode,which has put forward higher requirements for the environmental quality of egg-laying hen houses.At present,in order to meet the needs of ventilation and cooling of egg-laying henhouse in high temperature environment in summer,the wet curtain fan cooling system adopted by breeding enterprises has achieved a better cooling effect,but it also has defects and deficiencies.When the outside is in a high temperature environment for a long time,the cooling effect of wet curtain is obviously insufficient,and there are problems such as low air volume in the activity area of laying hens,low wind speed and excessively high temperature at the end of the chicken house,which damage the health of laying hens and reduce the laying rate.In this paper,the Computational Fluid Dynamics(CFD)method is used to solve the problems of uneven airflow distribution and excessively high temperature at the end of egg hen house under longitudinal wet curtain and fan ventilation(no side wall wet curtain)mode under high summer temperature in China.CFD for short)simulated and evaluated the thermal environment and ventilation environment of egg-laying hen house,and proposed the optimization design of adding roof diversion board on the beam structure of egg-laying hen house.Finally,simulated and analyzed the working conditions of roof diversion board in egg-laying hen house under four different angles.The main contents include:1.Through field data collection,Solid Works software was used to establish a THREE-DIMENSIONAL model,and ANSYS Fluent software was used to conduct three-dimensional steady-state simulation of the thermal environment and ventilation environment of the laying hen house.The simulation results showed that: The average relative error between simulated wind speed and measured wind speed and temperature is less than 10%,which verifies the reliability of the 3D laying house CFD model.The distribution of air distribution in the existing laying hens’ houses is not uniform,and the coefficient of air distribution is as high as 44.9%.In addition,the heat emitted by laying hens in the houses flows along the longitudinal flow and gathers at the end of the fan,resulting in high temperature at the end of the houses,and the temperature difference between front and back in the activity area of laying hens is about 5℃.2.In view of the shortcomings and defects of the existing thermal and ventilation environment of the laying house,in order to reduce the non-uniformity coefficient of air flow in the house,improve the wind speed of air flow in the activity area of laying hens and reduce the temperature at the end of the house,the optimization scheme of installing 8 roof deflectors with different angles on the beam structure of the laying house was proposed.3.According to the actual structure and installation convenience of the laying house,8 roof diversion plates were set under the truss of the laying house,and the distribution of air flow field and temperature field in the laying house was simulated under four working conditions(i.e.,30° roof diversion plate,45° roof diversion plate,60° roof diversion plate and 90° roof diversion plate).The simulation results showed that the roof diversion board installed in the laying hens house under longitudinal ventilation mode(no side wall wet curtain)could improve the environment of laying hens house,make the air distribution in the house uniform,and reduce the temperature at the end of the house.4.Simulation results show that the laying hens shed roof installation guide plate,the inner air flow to improve,90 ° roof installation guide plate work condition,the inner air distribution is relatively uniform,laying hens activity area wind speed obviously improved,the temperature of the laying hens activity area less obvious guide plate and cooling effect,the inner end temperature to slash. |
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