Flux Links to/from Network Pathways

The only way to transport mass out of a Network pathway A transport pathway element that provides a computationally efficient way to simulate large, complex networks of one-dimensional conduits in order to describe contaminant transport through fractured rock systems. is by specifying an advective mass flux link A mass flux link in which a quantity of a medium is specified to flow from one pathway to another, carrying dissolved, sorbed, and/or suspended species with it. to another pathway. For Network pathways, the flowing medium is always the Reference Fluid A special type of Fluid element that provides a basis for defining partition coefficients between media for the various species in the model (i.e., the ratio of the species’ concentration in the medium to its concentration in the Reference Fluid at equilibrium).. Diffusive mass flux links from Network pathways (diffusive outfluxes) and special purpose (direct transfer, precipitate removal and treatment) mass flux links from Network pathways cannot be created.

Note that the flow rate of the fluid defined in an advective mass flux link An interconnnection between two transport pathways that defines the rate at which species move between the pathways. from a Network pathway, if used at all, is only used to determine how mass from a single sink is apportioned between Outflow flux links.

That is, the mass flux link is used only to specify where the mass is to be discharged. The pipe flow rates within the fracture network A complex network of one-dimensional conduits used by a Network Pathway to describe contaminant transport through fractured rock systems. determine how mass moves through the pathway and the rate at which mass is discharged. Because the flow rates in the mass flux links to/from Network pathways do not impact the manner in which mass is transported, GoldSim does not test to ensure that the flows in the flux links to and from the pathway are consistent with the internal flows in the network pipes.

You can transport mass into a Network pathway via an advective mass flux link from any other type of pathway and/or via a diffusive mass flux link A mass flux link in which species diffuse between pathways according to a concentration gradient. from a Cell pathway A transport pathway element that is mathematically equivalent to a finite difference node. Cells are commonly applied to simulate discrete compartments in an environmental system (such as ponds, lakes, shallow soil compartments, or the atmosphere).. Within GoldSim, the concentration and diffusive length on the Network pathway side of a diffusive mass flux link are assumed to be zero. Hence, like advective mass flux links, diffusive mass flux links involving Network pathways are uni-directional.

Warning: GoldSim does not enforce a balance for the flow of the Reference Fluid in a Network pathway. That is, the Inflows into the pathway do not need to be equal to the Outflows from the pathway. Unlike Cells and Pipes, however, if the specified Outflows are less than the specified Inflows, it does not imply that the species The chemical (or non-chemical, such as bacterial or viral) constituents that are stored and transported through an environmental system in a contaminant transport model. In GoldSim, the Species element defines all of the contaminant species being simulated (and their properties). concentrations leaving the Network pathway would be greater than those entering the pathway. This is because not all of the mass than enters a Network pathway necessarily must exit the pathway, since you may choose to ignore some sinks (e.g., those that discharge to deep locations and effectively leave the system).