Simulation of friction on the wetted contact area of the pair «rotor-stator» in a two-rotor vacuum pump
DOI:
https://doi.org/10.31734/agroengineering2020.24.131Keywords:
vacuum pump, coefficient of friction, lubrication, fluid movementAbstract
The important factor that determines reliability of the product is the choice of structural materials from which the friction pairs of vacuum pumps are made. Therefore, development of the scientific and methodological basis for creation of their working bodies is a crucial task. Based on the analysis of scientific research, advanced production experience, patent search for vacuum pumps, we found that the operational and technological performance of rotary pumps is much better than other types. However, the technical and energy performance of vacuum systems such as reliability, compactness, the stability of vacuum pressure, supply, and noise do not fully meet all current requirements.
To increase the efficiency of a two - rotor vacuum pump the authors of the research eliminated the flow of air through the radial and end gaps, by installing the radial end zones of the working bodies of isotropic elastic plates and by applying lubrication of the contact areas of the friction pair «rotor-stator» with water.
The dynamics of the Newtonian wetting fluid (lubrication) is described by the Navier – Stokes equation. The experiment considers the fact that the fluid, being the lubricating medium, is a quasi-static flow. When the rotor rotates, the isotropic elastic insert width а deforms and creates a gap.
Simulation of the operation of a two-rotor vacuum pump, in particular the friction of the working bodies, in the presence of wetting the contact area of the steam «rotor-stator» led to a decrease in airflow through gaps and friction coefficient with an increasing angular velocity of the rotor. In this case, the nature of the change in the coefficient of friction is nonlinear and it is subject to the quadratic characteristic. When the angular speed of the rotor increases by more than 300 rad/s and we use lubricating fluid, the coefficient of friction decreases and approaches the linear characteristic.
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