Optimization design of an explicitly defined rack for the generation of rotors for twin-screw compressors

In conventional rotor pro. le generation for the twin-screw compressor, the designed parameters are often decided by trial-and-error method and cannot distinctly predict the changed difference when adjusting one of parameters. Refer to previous rack-generated rotor profiles, explicit equations of the rack with two specific normal-equidistant trochoids are first disclosed in this paper to replace the implicit form. The feasible parameters are designed on the rack in order to more instinctively and flexibly adjust each compound curve. The parametric study and non-undercut limits are presented for the rotor profile optimization with SUMT (sequential unconstrained minimization technique) method. A numerical example is presented to show the validation of the proposed optimization model and a practical experiment is conducted to test the excellent compressor performance. (C) 2008 Elsevier Ltd. All rights reserved.