Research On Shell And Tube Condensing System Of Logistics Vehicle With Vacuum Drying Function

Grain is not only an important food source for human beings,but also an important industrial raw material for the production of alcohol and starch.But the grain contains more water when harvested.Therefore,drying and dehydration has become one of the most important links in grain production.However,the speed of grain dehydration by natural methods such as ventilation and drying is slow.Hot air drying can improve the drying efficiency,but it has an impact on the quality of grain.After drying and transportation in the above way,the secondary moisture in the transportation process will make the grain quality unable to meet the standard.In view of the above problems,this paper designs a logistics vehicle with the function of vacuum condensation drying in the transportation process.Vacuum condensation drying is low-temperature drying,which can ensure the quality of grain,and can continue to dry grain in the long-term transportation process,which improves the proportion of grain drying to safe moisture.The main device of the vacuum condensation drying logistics vehicle is the vacuum condensation drying system.The main equipment of the system is composed of material mixing system,heat exchange system and vacuum circuit.The heat exchange system is the researchobject of this paper,and the condenser is the core heat exchange component.In order to achieve the best working performance of the condenser in the vacuum condensation drying system and improve the working efficiency of the vacuum condensation drying system,the main research of this paper is as follows:(1)A scheme of vacuum condensation drying system suitable for logistics vehicle is proposed,and the structure design and simulation analysis of shell and tube condenser are carried out.The results show that the temperature of cooling water in tube side increases and that of steam in shell side decreases,and the volume fraction of condensate increases along the heat transfer direction.(2)An experimental method of segmented measurement for shell and tube condenser was proposed,and the influence of cooling water temperature,flow rate and steam temperature on the heat transfer performance of the condenser under set vacuum pressure was studied.Through the experimental research and numerical simulation analysis of this paper,the foundation for the development of logistics vehicle with vacuum drying function is laid,and has a certain reference value.