低浓度甘蔗渣化学浆流变特性的研究

    Rheological properties of low consistency chemical pulp of bagasse

    • 摘要: 该文对不同浓度、打浆度、剪切速率对低浓度甘蔗渣化学浆流变特性的影响进行了实验研究,对不同因素引起浆料表观黏度变化的机理进行了分析,结果表明:随浆料浓度增加,纸浆表观黏度呈指数式增加;打浆度影响浆料的微观结构,随打浆度升高,纸浆表观黏度呈下降趋势;低浓度纸浆的表观黏度随剪切速率提高而递减。在实验测量范围内,甘蔗渣低浓度纸浆为满足幂律关系的非牛顿流体,拟合的本构方程的流变特性指数n<1,因此其在测量范围内为拟塑性流体。另外,随着纸浆浓度的降低,流变特性指数n增加,表明随低浓度纸浆逐渐变稀,所表现出的流变特性向着牛顿流体的方向趋近。低浓度纸浆流变特性的研究为纸浆模塑生产线流送系统提供了设计基础。

       

      Abstract: The rheological properties of low consistency chemical pulp of bagasse influenced by different consistencies, beating degrees and shearing velocities were studied experimentally, the mechanism of such changes on rheological property was also analyzed. The results showed that with the increase of pulp consistency, the apparent viscosities of pulp increased exponentially; the beating degree of pulp had an effect on microstructure of pulp, therefore the apparent viscosities of pulp decreased with the increase of beating degree of pulp, and the apparent viscosities of pulp decreased with the increase of shearing rates. Based on the above results, the rheological models for the low consistency chemical pulp of bagasse were also set up. In addition, from the experimental results, it is found that the rheological property indexes n are less than 1 wholly according to the drawn constitutive equations, which reveals that all the experimental low consistency pulp fluids can be described as pseudoplastic fluids whose relationship of rheological property indexes is in accordance with that of non-Newtonian fluid. Also, it indicates that the values of n increase as the consistency becomes lower, and shows that the rheological properties are close to that of Newtonian fluid when the pulp consistency getting lower. The property data of low consistency chemical pulp of bagasse can be used to model machine-products of pulp molding interactions taking place in the transferring equipment of pulp transferring system.

       

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