Zero-dimensional model of compressible gas flow in networks of pressure vessels: Program TRIC

A computational tool that models the flow of real gases of arbitrary equation of state in networks of pressure vessels connected by various flow components is described. The conservation equations in zero dimensions are applied to the vessels, which are treated as either constant or deformable control volumes, to produce a set of time dependent, ordinary differential equations. A flow model is developed for an isentropic process, appropriate to nozzles and short orifices, with the flow rate modified by a flow coefficient. For long ducts, the code solves the boundary value problem resulting from the one dimensional conservation equations. Friction and heat transfer in the duct are included in this flow model and a loss of total pressure is predicted, obviating a flow coefficient.