采用5种稳定风速和4种变动风速,研究排湿风速对微波干燥过程湿度、干燥速率及其干后品质的影响.结果表明,排湿风速对微波干燥的湿度、干燥速率和干后品质有明显影响.稳定风速时,风速越小,湿度峰值越高,高湿维持时间越长,干燥速率峰值越低.若风速改变,升速变动风速对湿度曲线影响不大,但对干燥速率曲线影响较为明显,尤其是在干燥前期和中期阶段升风,干燥速率会快速上升;降速变动风速时,湿度会明显上升或维持峰值不变,同时干燥速率降低,但降低效果并不明显.阶梯升速前期干燥速率低,后期变大,整个干燥过程湿度较大,干后品质最优.另发现,稳定风速干燥时,湿度曲线的变化由干燥速率决定,二者在整个干燥过程同步变化,且起伏趋势一致.变动风速下,湿度曲线和干燥速率曲线的同步变化被打破,湿度曲线的变化受风速和干燥速率变化的共同影响.%The effect of flow rate on humidity, drying rate and product quality in microwave drying process was stud-ied under 5 kinds of safe flow rates and 4 types of varying flow rates. The results showed that the flow rate had a sig-nificant effect on humidity, drying rate and product quality. The smaller the flow rate was, the higher the humidity was, but the lower the drying rate was, and the product quality was relatively better. Under varying flow rates, the results need to be discussed separately. If the flow rate was increased, the curve of the drying rate was affected obvi-ously, especially in the early and middle stages. If the flow rate was decreased, the humidity would go up obviously or keep stable. In addition, the drying rate would slightly go down, but the effect was not obvious. The quality of carrots was the best when the flow rate was increased stepwise, in which the drying rate was low in the early stage and then rose up stepwise in the middle stage. Besides, the experiments also showed a relationship between the humidity and drying rate. If the flow rate was safe, the humidity was determined by the drying rate. Two curves of humidity and drying rate rose up or fall down synchronously. Under varying flow rates, the humidity and drying rate no longer varied synchronously, and the humidity depended on the combined effect of flow rate and drying rate.
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