Design Of Cross Section For Counter-Rotating Twin-Screw Elements And Surface Reconstruction

This thesis consists of two parts. At first, Based on design theory of cross section of counter-rotating twin-screw, Algebraic condition for the existence of conjugate algebraic curves was obtained. Mathematic models of conjugate curves were deduced via enveloping theory and dentiform normal method. Because of the flexibility of enveloping method than dentiform normal method, three new screws are designed by enveloping method with flow field analysis. By comparing the flow, pressure field and average shear stress, effects of cross section on flow are concluded preliminary. Consequently, cross sections of screw can be designed according to flow effectively.Secondly, twin screw surfaces are reconstructed based on reverse engineering, firstly Initial 3D point clouds are obtained by scanning Twin-Screw element via 3D laser scanner. By pre-processing the initial...