考虑离心作用的螺杆挤出机固体输送理论分析

应用前文考虑离心作用和物料可压缩性建立的模型,考察了离心力对物料运动速度和加速度的影响,并分析讨论了固体输送段输送角、压力分布和固体输送段的长度,并和实验值作了对比。在固体输送段开始处牵引角最大,最大牵引角和螺纹升角是互补关系,此处压力最小,螺杆的离心作用最小,在固体输送结束处,牵引角最小,压力最大,螺杆的离心作用最强。物料与螺杆、机筒的摩擦热正比于局部压力,界面温度也密切服从于局部压力。压力温度关系对形成很高压力是一内在安全机理,挤出机自己可调节固体输送段中形成的极限压力。

Solid Conveying in Screw Extruder Considering Centrifugal Force and Compressibility

Based on the established model of solid conveying in screw extruder,the effects of centrifugal force and material compressibility on material velocity,acceleration,traction angle,pressure distribution and the required length for solid-convey were analyzed and the results were contrasted to experimental data.The maximum of traction angle is at the beginning in solid conveying corresponding to the zero pressure and minimum centrifugal force and the maximum of traction angle is supplementary to helix angle.The minimum of traction angle is at the end of solid conveying zone corresponding to the maximum pressure and minimum centrifugal force.Friction heat of barrel and screw on solids is proportional to local pressure and interface temperature also is corresponding to local pressure.Extruders can adjust the limited pressure in solids conveying zone by themselves through the relation of pressure and temperature which is the internal mechanism of extruders.