Thanks for reply.
I am working on a dynamic simulator (OTS) for power plants and refinery.And uptill now I am calculating disch pressure of pump equat to ( max pr - desired flow/max flow).But now another requirement has came that I need to include pump RPM, flow vs head curve,density of fluid.I am not able to find a set of equations which considers all these factors for getting same pump characteristics curves and other dynamics as given by DCS vendor.