The document discusses connecting internal streams within a sub-flowsheet to external streams in the parent flowsheet in HYSYS. Any internal streams that are not fully connected within the sub-flowsheet, called "open ended" streams, can serve as feeds or products. These potential feed and product streams, along with any other streams not connected to any units, will appear in the sub-flowsheet property view. To connect the streams between the flowsheets, the user specifies the name of the corresponding external stream from the parent flowsheet in the matrix opposite the internal stream name from the sub-flowsheet.
