转鼓中皮革运动特征及其对化学品传质的影响

Motion characteristics of leather in drum and influence on mass transfer for chemicals

皮革在转鼓内吸收化学品期间,会持续地受到浴液的冲刷和转鼓的机械作用,自身发生剧烈形变,因而化学品进入皮革的传质过程十分复杂。针对此过程,采用透明可视装置探究了皮革在转鼓内的运动特征,并分析运动参数对化学品传质过程的影响。研究结果表明:转鼓转速从8 r/min提高至16 r/min时,皮革平均运动速率会从185 mm/s增大至284 mm/s、平均加速度从516 mm/s~2提升至656 mm/s~2;其下降运动状态时间占比从59%增加至65%,化学品传质速率从31.19 mg/(m^(2)·s)提高至38.36 mg/(m^(2)·s),转速高时皮革的纤维分散度好,说明转鼓中皮革的运动特征随转速增大而明显变化,并对化学品在皮革内的传质速率有显著影响。

The mass transfer process during the leather absorbing chemicals in drum is significantly complicated,because the leather is severely deformed under the combined continuous washing from the bath liquid and the mechanical loads from the rotating drum.With aim to clarify the process,this study concerned the motion characteristics of the leather in rotating drum through transparent visual device,and thereby the effect of kinetic parameters on mass transfer was analyzed.The results show that with the drum rotating speed increased from 8 r/min to 16 r/min,the corresponding average velocity of leather rises from 185 mm/s to 284 mm/s and the average acceleration of leather grows from 516 mm/s~2 to 656 mm/s~2,time ratio of downward motion states changes from 59% to 65%,mass transfer rate of chemicals accelerates from 31.19 mg/(m^(2)·s) to 38.36 mg/(m^(2)·s),and the fiber dispersion of the leather becomes better.The research indicates that motion characteristics of leather in drum change obviously with the rotating speed increase,and have a significant effect on mass transfer rate of chemicals in leather.