Evaluation of the Lubrication Regime for Rotary Compressors. Influence of Thermal Expansions on the Minimum Film Thickness.

In this work, the lubrication regime of a rotary compressor is studied in the regions of the roller, cylinder, shaft, and bearings. A code is programmed so it can solve multiple cases with different suction-discharge pressures, angular velocity, viscosity, and geometrical conditions, among others. In order to study the lubrication regime, the balance of the different forces that act on the roller is computed. To calculate the oil pressure forces, the Reynolds equation coupled with an iterative method is used to find the minimal distance and pressure distribution that balances the external forces. This process is repeated for a discrete number of rotation angles to evaluate the overall rotation of a cycle. In addition, the effect that the thermal expansion of the different materials can have on the lubrication regime is studied. If the materials get too hot, the distances between surfaces might increase or reduce with respect to the distances at room temperature. These changes might lead to a point where the lubrication regime changes. The objective is to include this thermal expansion effect in the model and evaluate how it can affect the lubrication regime.The author Jordi Vera has been financially supported by the Ministerio de Educación y Ciencia (MEC), Spain, (FPI grant PRE2018-084017). The author E.Schillaci acknowledges the financial support of the Programa Torres Quevedo (PTQ2018-010060).Postprint (published version