I want to modeling of lubricant fiim in gearbox. Is there any paper or cfd method for this topic?

Lubricating films are usually modeled with a very simplified version of the NS equations, based on the assumption that the lubricating film is very thin. With this sort of reduction, the momentum equations can (sometimes) be reducted to velocities as functions of pressure. Those functions are then substituted into the continuity equation, yielding a Poisson equation for the film pressures. See Schlichting, Boundary Layer Theory, for example, for a development of this technique. You might also check your institution's technical library for lubrication journals.

Solving a Poisson equation numerically is usually much easier than solving the full fluid motion (Navier Stokes) equations numerically as a CFD problem.

I can't advise you as to the appropriate simplifications for a gear box. As a full CFD solution, it might be rather messy. If your interest is only for the small gaps between two meshing gear teeth, it might (??) be possible to set up a CFD problem in that limited region, providing you can figure out useful boundary conditions.

Good Luck!

Dear Hondor,

If you're interested in elastohidrodynamics modeling, please visit:

- http://www.ub.utwente.nl/webdoc/docs/wb.shtml

You may download wijnant's phd thesis

-http://www.scs.leeds.ac.uk/cpde/EHL_publications.html

(goodyer's papers)

Hope that helps

Pran