A model is presented for the dewatering of a saturated two-phase medium in a screw press. The model accounts for the detailed two-phase rheological behaviour of the pressed material and splits the press into two zones, an initial well-mixed constant-pressure region followed by an axial transport region in which the total pressure steadily increases. In this latter region, a slowly varying helical coordinate transformation is introduced to help reduce the dynamics to an annular bi-axial compression of the two-phase medium. Unlike previous modelling, the transition point between the two zones is determined self-consistently, rather than set a priori, and the pressure along the length of the press is deduced from the rheology of the two-phase flow rather than averaging the two-phase dynamics over a cross section of the press. The model is compared to experimental observations of the dewatering of a paper-making fibre suspension and of a clay slurry, and is shown to reproduce operational data.

中文翻译：

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用螺旋压榨机脱水饱和的网状悬浮液

介绍了在螺旋压榨机中脱水饱和两相介质的模型。该模型考虑了被压制材料的详细两相流变行为，并将压机分为两个区域，一个初始混合良好的恒压区域，然后是一个总压力稳定增加的轴向传输区域。在后一个区域，引入了缓慢变化的螺旋坐标变换，以帮助将动力学降低到两相介质的环形双轴压缩。与之前的建模不同，两个区域之间的过渡点是自洽确定的，而不是先验设置，并且沿压机长度的压力是从两相流的流变学中推导出来的，而不是对两相进行平均压机横截面的动态。