Development of an internal air cooling sprayed oil injection technique for the energy saving in sliding vane rotary compressors through theoretical and experimental methodologies

The present work highlights the energy saving potential of the lubricant fluid supplied in Sliding Vane Rotary air Compressors. A Lagrangian theoretical model of a sprayed oil injection technology assessed the cooling effect of the lubricant due to the high surface to volume ratio of the oil droplets and predicted a reduction of the indicated power. The model validation was carried out through a test campaign on a mid-size sliding vane compressor equipped with a series of pressure swirl atomizers. The oil injections took place along the axial length of the compressor. The reconstruction of the indicator diagram and the direct measurement of the mechanical power revealed a reduction of the energy consumption close to 7 % using an injection pressure of 20 bar. A parametric analysis on the injection pressure and temperature and on the cone spray angle was eventually carried out to identify an optimal set of operative injection parameters.