The Study On Drying Process Of The In-bag Drying Of High Moisture Paddy

The paper focuses on applications on In-Bag Drying of High Moisture Paddy and the CFD Technology used on the progress of paddy drying.Take the paddy newly gathered in 2014 as experimental resources.This paper analyses thin layer drying characteristics of the In-bag Drying by combining indoor thin layer drying experiments,outdoor drying experiments with the CFD technology.The main research achievements are as follow:1.The beginning characteristics of the In-bag drying.During the In-Bag drying process,temperature and humidity have significant different impacts on the changing of the moisture content and the drying speed.The higher temperature of the In-Bag drying is,the lower humidity is,and the faster moisture content rate changes.Meanwhile,moisture content decreases more rapidly with a higher speed of drying.When the humidity is 40%,the temperature of drying is 35?.The moisture content of paddy prepared for drying can reach the secure level to store in 32 hours.2.The impact of drying condition on the speed of in-bag drying and unit energy consumption.With different unit air flow and different weight of paddy in package,paddy with different original moisture contents have obvious different speed of drying and consume different unit energy.With the increasing amount of original moisture content,the drying speed increases firstly,and then decreases.The lighter weight of paddy in package is,the faster drying rate is.And the drying rate goes up when provided a stronger dry air flow.As to the influence on unit energy consumption of in-bag drying,the weight of paddy in package has the greatest impact,followed with the amount of original moisture content.And unit air flow has the smallest influence.There is a positive correlation among the unit energy consumption,weight of paddy in package,the amount of original moisture content and unit air flow of in-bag drying.In-bag drying exhausts more energy with higher weight,amount of original moisture content and stronger unit air flow.3.Parameter determination of optimum expectancy of in-bag drying.Adopting Design-Expert 8.05 software for regression analysis,multiple formulates models of in-bag drying rateand unit energy consumption have been established.By the analyses via software,we know temperature of air intake,unit amount of air flow and weight of paddy have a positive correlation with drying speed,but the negative correlation with weight of paddy in package.Temperature of air intake,unit amount of air flow and weight of paddy have a positive correlation with unit amount of energy consumption.And we obtain Parameter determination of optimum expectancy of in-bag drying by modals.When the temperature of air intake is 35?,the unit amount of air flow is 0.48m3/(kg.h)and weight of paddy in package is 600 kg,the speed of drying is maximum with 0.517079%/h,while drying unit energy consumption is minimum with 3.30935 ??thk W)(%.4.CFD Stimulation during the process of in-bag drying.By CFD simulation technology,the progress of drying from the bottom to the top layer by layer is more vivid observed.Comparing the actual value of temperature and moisture to the experimental ones,they are very close.That is to say,the CFD simulation technology can be used in the research of the In-Bag drying.Mixing the paddy of the bottom with the top can reduce not only the degree of over drying of the bottom ones,but also the time of drying.