CFD Numerical Study On The Flow Field,Temperature Field And Atmosphere In The Refrigerated Compartment

With material life becoming more and more abundant,people’s pursuit of food quality is gradually increasing,especially the demand for freshness and quality of fruits and vegetables.In order to improve the quality of fruits and vegetables in refrigerated transportation,an improved internal structure is proposed to improve the distribution of cooling capacity in refrigerated container.Firstly,a three-dimensional computational fluid dynamics model was established,and the porous media theory was used to simplify the stack.The resistance characteristics of the porous media were obtained by combining theory and numerical simulation,which was verified with data of previous paper.Secondly,three baffles were added to reduce the loss of cold airflow by blocking the airflow through air-gaps,and improve the uniformity of temperature distribution.Finally,to facilitate the study of modified atmosphere,three physical quantities were defined to measure the uniformity and efficiency of modified atmosphere.Based on the verified CFD(Computational Fluid Dynamics)model,the velocity and temperature of the previous refrigerated container and the improved refrigerated container were obtained and compared.The cold airflow distribution in the improved refrigerated container is more uniform.The improvement of vertical velocity in all stacks is in the range of 5.24%-425.04%.The cooling performance of the two refrigerated truck compartments were also obtained.The variation of temperature distribution is within±1 ~oC and the cooling time is also reduced by at least 22.9%in the improved refrigerated container.In addition,the temperature rise reduction rate of different fruits and vegetables is between 34.0%and 59.5%,which shows the applicability of the improved internal structure to different fruits and vegetables.In terms of atmosphere control,the improved internal structure significantly improved the uniformity of the atmosphere in the stacks for the refrigerated truck compartment without controlled atmosphere.In the refrigerated truck compartment with controlled atmosphere,this article fits the relationship between the air-conditioning inlet(outlet)with the atmosphere control time and compares the uniformity of the atmosphere.The results show that the improved internal structure improved the uniformity of the atmosphere distribution by about 28%,while the rate of controlled atmosphere increases by 18%-29.71%.