A MODELING AND SIMULATION LANGUAGE FOR COMBINED LUMPED AND DISTRIBUTED-PARAMETER SYSTEMS

This paper identifies a number of key issues regarding the development of general modelling languages for combined lumped and distributed pa rameter processes, and proposes one such language. The latter has been implemented in the gPROMS process modelling system and permits the ma thematical modelling of arbitrarily complex unit operations that are d istributed over rectangular domains in terms of mixed systems of integ ral, partial differential, and algebraic equations (IPDAEs). Following language translation, validation and analysis, the method of lines is employed automatically to convert the IPDAEs to sets of ordinary diff erential-algebraic equations (DAEs). The latter are then solved simult aneously with the DAEs that model the behaviour of the lumped paramete r units in the process. Three examples are presented to illustrate the capability of the proposed modelling system to deal with a wide varie ty of complex processes described in terms of IPDAEs.