Hydrodynamic Thrust Bearing

[enirwin]

I need to add a thrust bearing to an existing oil pump design. I would like to react the thrust with a simple thrust washer if possible to keep the cost down. I think I can approximate the thrust capacity of the thrust washer by treating it like two parallel disks with pressure applied from the center and oil flowing outward. Does anyone have the equation for pressure gradient as a function of the radius and the gap between disks? With this I can determine how much pressure and how large a washer I need to react the thrust. I've looked through my Fluids texts and one of them has this case as an exercise, but I've been out of school too long to do the derivation (assuming I could have done it when I was in school). Any help would be appreciated.