I have been working in dyrobes to design suitable bearings for new compressor and turbine design. I am facing trouble finding details on journal bearing load calculation. W= w1 + w2 x rpm^2 + w2 x rpm^3 W is the total load but how do I calculate w1 , w2

I don't understand why the load on the journal bearing would be a function of speed only. Wouldn't this be dependent on the external mechanism that the journal is supporting? Why is there no mass*gravity term? Where is the function you show from?, it seems very strange. It looks like it is a curve fit function in which case the constants may come from a lookup table and not from a calculation. Can you give more details?