Design parameter study to extend the capacity range of dry twin screw compressors

The possibility for extending the capacity range oil-free dry twin screw compressors has been studied. Basic geometry parameters influence on compressor performance derived. two shaft speed and rotor diameter are critical. lower limit depends maximum acceptable speed, considering bearings, gearbox or power electronics. higher size, machining costs tolerances large diameters. Thermodynamic efficiency optimal tip dependent internal throttling leakage losses. Simplified analytical modelling applied, neglecting detailed with minor performance. kinematic relations give as non-dimensional specific displacement, (moderately of machine size), capacity. also define dependence these three parameters, displacement; profile geometry, i.e. number lobes, lobe depth/diameter, male width/diameter; well length/diameter ratio wrap angle determine displacement. displacement is hence independent size Also path lengths in mesh between rotors casing, outlet port will be determined by major parameters. Here means relation to diameter. A fixed pressure (volume ratio) assumed. simplified computerized model was developed calculate necessary data particular from basic For case constant clearances (non-dimensional), constant, absolute clearances, slightly simplified, non-female addendum, point generated, asymmetric Rotor details have then omitted. cylindrical part would allow a bigger while maintaining built-in volume ratio. theoretical results this study indicate that should primarily lobes depth, result enable design than commonly used 4:6 configuration, without exceeding drive train high constraint. reduced (rotor diameter). It having problems too Considering both potential extension efficiency, low fewer e.g. 2:4, might most promising option.