[Prikane]

Elastohydrodynamic Lubrication is typical regime of lubrications for machine components such as bearings, cams and gears.

Traditionally, the Reynolds equation has been used to describe the flow of a lubricant for the TEHL problem, but this approach has some limitations (it does not model cavitation region). To overcome these, I am using CFD, as an alternative to solving the Reynolds equation.

For the purpose of resolving this problem, I already created highly structured and high quality mesh, using ANSYS ICEM CFD.

In this research, the mixture model is employed to model the liquid and vapour phases in the EHL flow. The liquid phase is assumed to be a continuous flow and a secondary phase is applied as a dispersion that comprises bubbles.

The most difficult part of this analysis, represents coding (using C language), of the User-defined functions (UDFs), for the heat generated in the lubricant film, the density and the viscosity of lubricant (as the functions of pressure and temperature), and the elastic deformation of the cylindrical roller bearing (in which full cavitation model for negative pressure solving needs to be incorporated). I have found these UDFs on internet, and they are 100 % correct.

Through research I have received deep insight into analytical analysis of physical characteristics of lubricants in EHL regime of lubrication, but I have trouble with setting proper analysis parameters in Ansys Fluent since this is the first time I am facing with Fluent. I need help in order to properly compile and hook mentioned UDFs, to create mixture model in order to model the liquid and vapour phases and to make solution converge in order to get variables of primary interest such as: film thickness, pressure, temperature, velocity, friction coefficient.

If there is someone who can help me with this problem, or someone who is working also on this problem, please let me know.

[chrissotirkos]

Hi, do u still have the udfs? It would help me!
Thank you

Originally Posted by prikane

elastohydrodynamic lubrication is typical regime of lubrications for machine components such as bearings, cams and gears.

Traditionally, the reynolds equation has been used to describe the flow of a lubricant for the tehl problem, but this approach has some limitations (it does not model cavitation region). To overcome these, i am using cfd, as an alternative to solving the reynolds equation.

For the purpose of resolving this problem, i already created highly structured and high quality mesh, using ansys icem cfd.

In this research, the mixture model is employed to model the liquid and vapour phases in the ehl flow. The liquid phase is assumed to be a continuous flow and a secondary phase is applied as a dispersion that comprises bubbles.

The most difficult part of this analysis, represents coding (using c language), of the user-defined functions (udfs), for the heat generated in the lubricant film, the density and the viscosity of lubricant (as the functions of pressure and temperature), and the elastic deformation of the cylindrical roller bearing (in which full cavitation model for negative pressure solving needs to be incorporated). I have found these udfs on internet, and they are 100 % correct.

Through research i have received deep insight into analytical analysis of physical characteristics of lubricants in ehl regime of lubrication, but i have trouble with setting proper analysis parameters in ansys fluent since this is the first time i am facing with fluent. I need help in order to properly compile and hook mentioned udfs, to create mixture model in order to model the liquid and vapour phases and to make solution converge in order to get variables of primary interest such as: Film thickness, pressure, temperature, velocity, friction coefficient.

If there is someone who can help me with this problem, or someone who is working also on this problem, please let me know.