Modeling And Testing The Thermal Effect Of Lubricating Oil Sprayed In Sliding-Vane Air Compressors Using Pressure-Swirl Nozzles

A number of studies report the benefit of proper oil spraying in positive-displacement compressors. This work presents a thermodynamic model for simulating sliding-vane air compressors that employ an injection system for the lubricating oil based on both plain orifices and pressure-swirl nozzles to exploit the thermal effect of sprayed oil inside the compression chambers. An experimental campaign on a large-size compressor is conducted measuring, among all, the pressure within a chamber. This measurement is used to validate the model. Oil droplet diameters depend strongly on the injection technology, nozzles generating a finer atomization than orifices, as well as the differential pressure. In any case, the proper positioning of the nozzles allows for an effective heat transfer from the air to the oil.