Experimental Investigation of the Distribution of Two-Phase Flow in Oil-Injected Twin-Screw Compressors

Oil-injected twin-screw compressors are the dominating compressor type in the industry. Compressors differ, depending on the manufacturer, in the rotor profile, the lobe number combination, the rotor diameter ratios, the wrap angle, the oil injection position, the oil injection quantity, etc. Historically, they all were probably mainly designed and optimised by trial and error, e.g. by experimentally varying the oil injection quantity, the injection nozzle and its position, or by modifying the profile. However, for some years now, computational modeling has taken an increasingly large part. Although the efficiency of the compressors is satisfying, there is still a remaining potential for improvements. In order to optimise machines by simulation a detailed knowledge of the loss mechanisms due to oil in the working chambers and approaches for their calculation are required. Therefore, for this work, as a first step for developing these models a series compressors’ housing is exchanged with a transparent glass housing in order to visualise the oil during the whole working process. First approaches for calculating the hydraulic losses are proposed and analysed in combination with the measurements.