A Numerical Method for Reversely Generating a Pair of Conjugated Rotor Profiles of Twin-screw Compressor from the Measured Profile Data

Reverse engineering technique is generally practiced to reconstitute the original conjugated rotor profiles from the measured point data with profile deviation for further evaluating performance of the competitor's same-level products in the twin-screw compressor manufacturing industry. However, it is time-consuming when synthesizing and restoring the original rotor profiles via either trial or enveloping methods. This paper proposed a numerical method, named meshing clearance elimination (MCE) method, for approaching pairs of conjugated male and female rotor profiles from the discrete measured profile points. By using this method, the clearance between two screw rotors can be attained via the normal rack generation computation and then eliminated by proportionally distribute the normal compensation onto the measured rotor profiles to obtain the "ideal" rotor profiles to avoid numerical divergence in the following compressor performance computation. Two kinds of rotor profiles measured from CMM (Coordinates Measurement Machine) were demonstrated in the numerical examples to show the effectivity and advantages of the MCE method.