CFD Simulation Of Piglet Environment Parameters And Ventilation Optimization Design

The airflow speed,temperature and concentration of harmful gas in the pigsty are the main factors affecting the health and production performance of pigs.an assessment and analysis of the environmental parameters in the pigsty can effectively find out the environmental problems in the pigsty,and put forward reasonable optimization schemes to solve the problems,so as to improve the environmental quality in the pigsty,improve the production performance and reduce the economic losses.In this paper,computational fluid dynamics（CFD）technology was applied to evaluate and analyze the environmental quality（wind speed,temperature,CO₂ concentration）of piglets and optimize the ventilation structure.On the one hand,the research results can provide theoretical basis and guidance for the scientific design of the ventilation system and structure of piglets.On the other hand,mastering the distribution law of environmental parameters in piglets can effectively improve the level of feeding management and realize the maximization of economic benefits.With longitudinal natural ventilation for the test way of weaned piglets shed as the research object,on the basis of the field measured environmental factors,using the ANSYS software to establish three-dimensional model of 1:1,using CFD technology to natural ventilation piglet air velocity,temperature,CO₂ concentration in three-dimensional steady-state numerical simulation,analysis,evaluation,found that the flow field,temperature field,the problems existing in the CO₂ concentration field,and put forward reasonable optimization scheme in view of the problems,establish a model to research,the results are as follows:（1）Field measurement in piglet shed.3d model was established based on the measured data,boundary conditions were set,and the measured value was taken as the truth value to evaluate the accuracy of simulation results.The results showed that the relative errors of the air flow field,temperature field and CO₂ concentration in the six environmental measurement points ranged from 0.2%to 30%,2%to 13%,and 4.3%to24.2%,respectively.The measured values and the simulated values were not significantly different,showing the same distribution law.The results prove that the software FLUENT can be used to simulate the distribution law of the indoor environment.（2）The airflow,temperature and CO₂ concentration of piglets in longitudinal natural ventilation mode in winter were simulated.The simulation results were as follows:within the activity range of piglets,the wind speed was lower than 0.1m/s in the area with the breathing level of 0.4m,and there was a large area of airflow stagnation in the second half of the pigpen.Temperature distribution in the range of 15²1℃,the air inlet end get average temperature around 16℃,the average temperature 19℃;CO₂ concentration ranged from 0.16%to 0.25%,with an average concentration of 0.19%.The house temperature and CO₂ concentration could not meet the environmental requirements of piglets.（3）On the basis of the original structure of the pig house,two ventilation optimization schemes were designed to solve the defects of the current ventilation methods,establish models and conduct numerical simulation of environmental parameters.Scheme 1 is bottom to top vertical ventilation and scheme 2 is top to bottom vertical ventilation.The simulation results of the two optimization schemes were analyzed,and the following conclusions were drawn:both schemes 1 and 2 could improve the low temperature and high CO₂ concentration in the active area of pigs,and the CO₂ concentration in the shed decreased with the increase of wind speed.However,as the cesspool USES different methods to discharge harmful gas,the average CO₂concentration in plan 2 is slightly higher than that in plan 1,so plan 1 has the best effect on improving the environment in the pig house.