Study On Drying Experiment And Equipment Of Solar Hot-air And Vacuum Combination

Drying is an important part of the deep processing of agricultural products,with the continuous development of drying technology,drying methods and all kinds of drying equipment are increasingly growing.Among them,Combined drying equipment that combines the advantages of a variety of single drying technology to achieve complementary advantages of drying technology has a good prospect.In this paper,on the basis of the solar combination drying equipment in the laboratory,the drying process of fruits and vegetables is researched.It provides the theoretical and technical basis for the modular design of the combined drying equipment.In addition to that,the design of the experimental combination drying equipment is optimized to achieve the requirements of low energy consumption,and high drying efficiency and high product quality.In this paper,the combination drying process of fruits and vegetables is researched in the first place.The hot air and vacuum combined drying experiment is carried out with fruits and vegetables as the experimental materials.The poor analysis and variance and the Duncan multiplicity analysis of the results are accomplished by the intuitive method and Excel and SPSS data processing software.The influence of the experimental factors on the experimental results and the ideal drying process scheme are obtained.Through the study of drying experiment,there are two problems of the existing drying equipment is found:(1)Although the drying tests of fruits and vegetables are carried out in summer,the water temperature of the solar water heating system is low.The auxiliary heating time is longer,and the energy consumption is higher in the process of drying;(2)The fruits and vegetables are dried unevenly in the hot-air drying stage.In other words,the material in the upper and lower trays have a big difference in the degree of dehydration,so the quality of products is poor.The study of the combination drying process of fruits and vegetablesprovides the theoretical basis for the structural design of the drying equipment.In order to solve the first problem,the solar water heating system is analyzed and designed.The calculation,analysis and comparison of several typical solar collectors are completed.Two sets of ?58×1800mm×35 full glass vacuum tube collector and a 500-liter cylindrical heating storage tank should be applied to the solar collector system.It makes the current temperature of hot water rise from 60? to 80?in summer.In view of the uneven drying problem,in this paper,two new structures of drying oven are designed.They are on the basis of the structure of traditional experimental drying oven to be designed by changing the way of hot air enters the oven.In this paper,the Solidworks 3D modeling software,Gambit grid partitioning software,FLUENT analysis software and Tecplot post-processing software are used for completing the task.They are applied to verify,analyze and compare the design schemes for choosing the better structural design.It is carried out numerical simulation analysis on the experimental traditional drying device and two new ones that are static pressure parallel air supply drying device and lateral hanging drying device.The simulation results of the hot air velocity field and the temperature field are analyzed and compared in the three kinds of drying device.The conclusion is drawn that the structure of the lateral hanging drying device is the better design scheme.Then the influence of the angle of side inflatable chamber of the lateral hanging drying device on the flow field distribution is further analyzed.The width h of the side inflatable chamber is changed and numerical simulation analysis is carried out on the drying device.That further verify the rationality of the design and determine the size of the structure.The design of the structure of the new combination drying equipment is completed.The design of the new combined drying device solves the problems of drying unevenly and high energy consumption of the experimental traditional drying device.It improves the drying rate and the quality of products and shortens the drying time.The design of the new experimental combination drying equipment has a certain reference value for the design of large-scale combined drying equipment applied to the drying industry.The study of this subject provides a theoretical basis for the further development of the processing technology of drying fruits and vegetables.At thesame time,it plays a important role in the design of the drying equipment and the application of solar energy in drying equipment.It has an important reference value for the study of the design and popularization of large-scale solar energy combined drying equipment in the drying industry.