果蔬热风穿流干燥换向通风的研究
Study on Vegetable and Fruit Drying by Alternating-direction Hot-air Penetrating
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摘要: 以豇豆为典型物料,利用热风穿流干燥试验台,进行了换向通风干燥的试验研究,得出了不同换向时间对干燥过程的影响规律,及其与能耗关系的回归方程式,得换向时间为0.5h时,能耗最低的结论,并在箱式穿流干燥机上进行了验证试验。Abstract: The result of study and test on alterating direction hot-air drying with compeas as a kind of typical vegetable and fruits was described. The drying test was carried out on the hot-air penetrating drying test-bed. There were twelve layers of vegetable and fruits in the drying test tank. The initial moisture content of compeas was 88%~89%.The hot - air reversion time varied by 1/2 hour interval from 1/2 hour to four hours. The average ladder of the moisture content of different layers of vegetable and fruits was used as an index to estimate the evenness of distribution of drying.The results showed that alternating direction hot-air drying had important effect upon the evenness of drying espe-cialy in the middle period of drying.The study on the effect of different hot-air reversion time upon the drying process gave drying curves and drying speed curves showing that alternating direction hot-air could increase drying rate in the initial and middle periods of drying. In the middle and last periods of drying the drying rate was much less than that of drying with no alternating direction hot-air. By means of alteruating direction hot-air drying time could be shortened.From studying the influence of hot-air reversion drying upon energy consumption, regression equation of hot-air reversion time and energy consumption could be obtained (y=3. 347341 + 0. 089777x2). When hot -air reversion time is 0. 5 hour, energy consumption was the towest.