Optimum Lobe Tip Designs in Oil Injected Helical Twin Screw Compressors

The effects of lobe tip design parameters on compressor performance were evaluated by utilizing a computer simulation package and taking SRM-D asymmetric type rotor profile as an example. The result suggests that the requirements for high efficiency, large capacity, low inter-rotor contact force and low viscous friction loss do not always lead to the use of the same lobe tip designs. Of all the tip parameters, special attention should be given to the male rotor crest range angles and the female rotor addendum, since they have a greater influence than all other rotor tip parameters. A c NOMENCLATURE Addendum of the female rotor, mm Centre distance between the male and female rotors, mm Radius of the male rotor tip segment, mm Radius of the male rotor minor circular arc, mm Lobe numbers of the male and female rotors, respectively Leading angle of the male rotor tip segment, deg Trailing angle of the male rotor tip segment, deg