Simulation Study Of Air Flow Field And Temperature Field In A Livestock Truck Based On CFD

With the improvement of people’s living standard and the increasing demand for pig quality,the demand for pigs is increasing year by year.In order to meet the market demand,some special vehicle manufacturers have developed new type of van type pig transporters.Compared with the fenced pig transporters,the van type pig transporters have unique advantages.However,during long-distance transportation,how to ensure that the environment inside the van meets the survival needs of pigs and reduces mortality has been the focus of attention in this industry.Therefore,it is necessary to conduct a simulation study to investigate the airflow organization distribution and temperature field evaluation inside the compartment.In this paper,a company’s pig transport carriage is selected as the research object to address the problems of uneven air flow and high temperature at the end of the carriage under the forced ventilation mode of high temperature in summer.The distribution of air flow and temperature field of the vehicle under no-load and full-load conditions is simulated by computational fluid dynamics(CFD)method,and the optimization scheme for the full-load condition is proposed and simulated.Finally,two optimization schemes are simulated,and the main contents of the study include:(1)collecting data through the real vehicle,using the pre-processing software ANSA to process the model,meanwhile measuring and analyzing the temperature and wind speed at key locations inside the compartment,and finally using the STAR-CCM+ software to carry out 3D steady-state simulation of the airflow temperature and airflow wind speed inside the compartment pig transport car,and comparing with the actual measured values.The results showed that the maximum relative error between simulated and measured values was 7.6% at no load,and the NMSE of temperature at the measurement point was only 0.0053(<0.25).Wind speed value relative error range of 10% or less in 16 points,the maximum relative error of 11%,the measured point wind speed NMSE of 0.0026(<0.25),the simulated value and the measured value of a high degree of agreement,the use of STAR-CCM + software simulation of the wind speed field and temperature field inside the compartment is reliable.(2)By analyzing the results of temperature and wind velocity fields in the compartment under simulated full load conditions,it was found that the temperature at the end of the compartment was higher than the front of the compartment,and the temperature at the upper level was higher than the lower level,and there was a more obvious dead zone of airflow at the location near the exhaust port,and the average wind velocity was only 0.9m/s,which was lower than the comfortable wind velocity of pigs by 1m/s,which was not conducive to the heat dissipation of the skin surface of pigs in the compartment;the average temperature was high,and the temperature The average temperature was high,and the temperature was maintained at 32℃,and the pigs in the compartment were easy to have stress reaction.(3)In order to avoid the stress reaction of pigs in the process of transporting pigs,in order to improve the air velocity in the active area of pigs and reduce the temperature at the end and the upper layer of the compartment as the optimization target,the optimization plan was proposed to change the diameter and the number of air supply round holes and increase the number of air supply ducts in the compartment.The results show that after changing the diameter and number of air supply holes and increasing the number of air supply ducts under full load,the airflow in the compartment is improved,the uniformity of temperature field is increased by 30% compared with the original model under full load,the air speed in the pig activity area is significantly increased,and the temperature at the end of the compartment is significantly reduced compared with the simulation results of the original model under full load.