A universal rotor design method for twin-rotor fluid machines with a parameterized sealing line considering inter-lobe clearances

The sealing line is a major leakage path affecting various performances of twin-rotor fluid machines (TRFMs). The rotor profile generation methods using a sealing line proposed previously are improvable further. A key factor, inter-lobe clearance, can be considered at the initial design stage of rotor profile; and a more universal model suitable for opened and closed sealing lines can be studied further to generate varied rotor profiles for different applications. Therefore, this study proposes a parameterized sealing line (PSL) with predefined inter-lobe clearance as a universal method, named the gap-distributed sealing line (GDSL) method, to generate the rotor profile for varied twin-rotor fluid machines. The PSL with opened or closed forms is predefined by explicit equations to generate different rotor profiles more flexibly. The inter-lobe clearance is directly given and distributed along the PSL to form a pair of rotor profiles with a gap. Additionally, the proposed method is also used to generate a conical rotor profile. The results presented in the numerical examples verify the flexibility and practicability of the proposed method. •A universal parameterized sealing line (PSL) with opened or a closed form is proposed.•Various types of rotor profiles for twin-rotor fluid machines are generated using the PSL.•Inter-lobe clearance between two rotors can be pre-considered on the PSL in advance of rotor profile design.•Conical screw rotors are able to be generated using the PSL.