Abstract: A computer program is disclosed for specifying and solving a fluid transfer problem. Schematic manager means are provided for generating and modifying a pictorial representation of a fluid system schematic having a plurality of components. The schematic manager means Is fluid and process independent. Replicator means are provided for generating a set of simultaneous equations from the pictorial representation and for assuring that the schematic manager remains fluid and process independent. A generic run-time simulation module is provided for solving the set of simultaneous equations, thereby allowing the computer program to adapt to variations in component state and fluid state as a function of system parameters. A fluid and property database manager is invoked by the simulation module, for allowing simulation of fluid flow processes having fluid states which may be unknown at the time of model creation.