差速螺旋啮合双转子端面型线的统一几何设计及模拟.PDF

53 3 Vol.53 No. 3 2017 2 JOURNAL OF MECHANICAL ENGINEERING Feb. 2017 DOI 10.3901/JME.2017.03.051 ( 100029) λ 3:1Polyflow TH122 United Geometrical Design and Simulation of Sectional Profiles for Twin Rotors in Differential Screw Coupling WANG Kejian WANG Tingfei (College of Mechanical and Electrical Engineering, Beijing University of Chemical Technology, Beijing 100029) Abstract For comprehensive description of differential rotors’ sections, one united geometrical design model is developed using relative motion method by introducing minus-plus transition coefficient λ for design sectional profiles of both co-rotational and counter-rotational twin rotors. From which, different types of novel rotors’ sectional profiles can be established by varying differential ratio and screw head number as well as other structural parameters. As an example, the model is used to form one mixing part constituted from double screw rotors of the same diameter and the different screw pitches with differential ratio of 3:1 either in co- or in counter-rotation. Polyflow software is used in finite element analysis numerical simulation of high density polyethylene melt in flow mixing for both coupling directions. It is shown that double differential counter-rotors exhibit uniform, longer residence time and smaller range of residence time distribution showing better distributive mixing capability in contrast with stronger extensional mixing and shear function showing better dispersive mixing capability for double differential co-rotors. Key wo