A double-lobe type rotor design process includes a process for forming a defined rotor and a process for forming a conjugate rotor, wherein the defined rotor and the conjugate rotor intermesh and conjugate to each other. The rotor profile curves suitably for the completed operation period of carryover, suction and exhaust could be well defined by proper parameters, thereby optimizing rotor performance, enhancing compression ratio, providing a smooth suction and exhaust process and avoiding noise and vibration.
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