Calculation on the Inter-Lobe Clearance Distribution of Twin-Screw Compressor by Optimization Method

Small rotor clearance is today a vital prerequisite for an efficient screw compressor. The clearance will increase compressor leakage, and thereby minimize both the volumetric and adiabatic efficiency. But, the inter-lobe clearance is necessary for compressor running. Therefore, a mathematical apparatus to quantify the inter-lobe clearance is precondition of taking a reasonable inter-lobe clearance. An optimization method is presented in this paper in which the inter-lobe clearance is calculated as the minimum distance between the two rotors along the contact line. And the actual position of the rotors in running state was considered, in which the rotors contacted with each other in the drive surface. Therefore the calculation of inter-lobe clearance is transformed to the calculation of the minimum distance distribution between the two rotors along the contact line in contact state. The results show that this algorithm obtains full inter-lobe clearance between the two rotor surfaces with higher accuracy.