Simulação numérica de graxa em vedantes labirinto

Abstract

The problem of contamination of bearings by debris from the external environment is explored through numerical simulation in labyrinth seals. The present work uses the commercial software FLUENT 16.0 of finite volumes for analysis of the flow of grease in the seals. The fluid is modeled as Herschel-Bulkley and implemented in the software through a User Defined Function (UDF) based on the Papanastasiou model. The operation of seals is approached and during the simulations the variables responsible for influencing the flow behavior are explored. The numerical application of the rheological model is validated with the analytical solution of the flow between flat and parallel plates. Through three case studies where the variation of radial and axial seals, grease variation and rotation are evaluated, it was concluded that radial seals are more efficient in the bias of less viscous friction losses and watertightness against contaminants. The variation of the grease allowed to visualize larger values of τy favor the expansion of non-shear regions. As well as greases with lower values of n reduce viscous moment losses due to reduction of frictional losses. The study of the effect of the rotation speed on the properties of the labyrinth seal made it possible to verify the increase of the grease mass flow due to the reduction of the effective viscosity, which in turn increases the viscous moment of the labyrinth.