考虑离心作用的螺杆挤出机固体输送理论模型

Modeling Solid Conveying in Novel Screw Extruder Considering Centrifugal Force and Compressibility

在固体输送段,物料由散粒体逐渐被压缩,形成压力梯度。离心力对固体输送有较大的影响,由于离心力的作用,物料与机筒之间的径向作用力大于物料与螺杆之间的径向作用力。在固体输送段压力沿螺杆轴向逐渐增大,输送角逐渐减小。文中根据实验现象,考虑离心力,建立了可压缩体的固体输送物理模型,并求出数学模型的解析解。理论计算表明,即使机筒与固相的摩擦系数小于螺杆与固相的摩擦系数,仍会有固体输送。

As observed, centrifugal force and material compressibility are important for setting up pressure in solid conveying zone of screw extruder. The solids compressed gradually in solid conveying zone and this induced the building of pressure gradient. The force on solids by barrel is larger than that by screw owing to centrifugal force. Pressure is increased gradually while traction angel is decreased gradually in screw axial direction. One model considering both centrifugal force and material compressibility is first developed and the analytical solutions are obtained. By the theory, it is concluded that solid conveying can still be carried out even though the friction coefficient between barrel and solid is smaller than the friction coefficient between screw and solids.