床层不均匀对散羊毛干燥过程的影响

THE INFLUENCE OF UNEVENNESS OF THE WOOL MAT ON THE DRYING OF LOOSE WOOL

以均匀床层模型为基础,用数值方法分析了羊毛床层不均匀性对抽气转鼓干燥机性能的影响。重排后的床层厚度沿转鼓宽度的分布以下列幂函授描述:y=bexp(-k/w)其中,参数k定义为厚度不均均因子;b为极限厚度。计算结果表明,羊毛在转鼓上的不均匀分布导致干燥产物平均湿含量增大,湿含量不均匀性增大从而产品中干燥不足和过干燥羊毛的百分率增大,同时干燥机生产能力降低。因此,对工业实践来说十分重要的问题是:干燥机进料装置的设计和操作应使进料羊毛尽可能均匀地分布在转鼓上。

The influence of the unevenness of the wool mat en the overall performance of the suction-drum dryer is analysed numerically with the model for the dryer processing an even wool mat as the basis. A rearranged distribution fun-ction of the wool mat thickness over the drum width is introduced, being desc-ribed mathematically by the exponential function with the parameter k defined as the unevenness factor and b the limiting thick-ness. The results of the calculation show that the uneven distribution of the wool mat on the drums causes an increased moisture content variation,and thus the increased percentages of both underdr'y and overdry wool in the product, with also a decreased throughput of wool. Therefore it is essential for indus-trial practice that the feed wool is distributed onto the drums as uniformlly as possible.