A numerical approach to predict cavitation and contact in misaligned journal bearings

Lombera Rodríguez, Hassán (2017). A numerical approach to predict cavitation and contact in misaligned journal bearings. Tesis (Doctoral), E.T.S.I. Telecomunicación (UPM). https://doi.org/10.20868/UPM.thesis.49143.

Descripción

Título: A numerical approach to predict cavitation and contact in misaligned journal bearings
Autor/es:
  • Lombera Rodríguez, Hassán
Director/es:
  • Tello del Castillo, José Ignacio
Tipo de Documento: Tesis (Doctoral)
Fecha: 2017
Materias:
Escuela: E.T.S.I. Telecomunicación (UPM)
Departamento: Matemática Aplicada a las Tecnologías de la Información y las Comunicaciones
Licencias Creative Commons: Reconocimiento - Sin obra derivada - No comercial

Texto completo

[img]
Vista Previa
PDF (Document Portable Format) - Se necesita un visor de ficheros PDF, como GSview, Xpdf o Adobe Acrobat Reader
Descargar (6MB) | Vista Previa

Resumen

This dissertation presents a numerical approach to reach the equilibrium position of a misaligned journal bearing with radial loading. We consider the hydrodynamic Reynolds equation with cavitation phenomenon, through both Reynolds and Elrod–Adams models. The device consists of an external cylinder surrounding a rotating shaft, both separated by a lubricant to prevent contact. The unknowns are the pressure of the lubricant satisfying a proper cavitation model, and the shaft position which could be misaligned. We couple the hydrodynamic model to Newton’s second law, which describes the position of the shaft. This is considered an inverse problem where the coefficient of the equation is given by the unknown shaft position, which depends on the pressure. Considering the Reynolds cavitation model, we solve the direct problem minimizing a convex functional. We use a preconditioned conjugate gradient method modified with projection and restarting strategies to account for cavitation. To solve the associated inverse problem we use an interior, trust-region algorithm subject to bounds, through which we transform the constrained optimization problem into an unconstrained one. The simulations show the existence of contact points for finite loading when misalignment occurs. We provide a mathematical proof for the point contact case. Similarly, we present the admissible range of misalignment angle projections for prescribed values of the shaft eccentricity and angular coordinate. With the Elrod–Adams model, we approximate the Heaviside function by a third order Hermite polynomial and solve the direct problem by minimizing a convex and lower semi continuous functional. To solve the associated inverse problem we introduce Ant Colony Optimization, an approach inspired by the ants’ foraging behaviour and communication through pheromone trails. This approach, originally developed to solve discrete optimization problems has been now successfully extended to continuous domains. Numerical results are presented to verify the different numerical approaches. To validate the proposal the predicted pressure values, in the bearing mid-plane, are compared to published experimental data.

Proyectos asociados

TipoCódigoAcrónimoResponsableTítulo
Gobierno de EspañaMTM2013-42907-PSin especificarJosé Ignacio Tello del CastilloProblemas inversos en lubricación industrial y otros problemas no lineales

Más información

ID de Registro: 49143
Identificador DC: http://oa.upm.es/49143/
Identificador OAI: oai:oa.upm.es:49143
Identificador DOI: 10.20868/UPM.thesis.49143
Depositado por: Archivo Digital UPM 2
Depositado el: 06 Feb 2018 07:54
Ultima Modificación: 06 Ago 2018 22:30
  • GEO_UP4
  • Open Access
  • Open Access
  • Sherpa-Romeo
    Compruebe si la revista anglosajona en la que ha publicado un artículo permite también su publicación en abierto.
  • Dulcinea
    Compruebe si la revista española en la que ha publicado un artículo permite también su publicación en abierto.
  • Recolecta
  • InvestigaM
  • Observatorio I+D+i UPM
  • OpenCourseWare UPM