Power -Steam Header Model

The Steam Header simulates a steam header by distributing steam to the outlets to meet steam demands.

 

The Steam Header is normally used with one or two control streams which are attached to steam supply streams. The Steam Header adjusts the flow in the steam supply streams to balance the flow around the header.
Control streams and their attach steam supply are adjusted in order. Control stream 1 is increased first and decreased the ast.
While not required, the Sky Steam stream should exist. The Steam Header uses the Sky Steam stream during intermediate iterations and for the case when the steam supply exceeds the steam demand.

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Data Description

Data Unit Description
Set Item Type Native
Equipment Properties MinFlow1 Mass Flow lbs/hr Minimum flow in the 1st control stream.
MaxFlow1 Mass Flow lbs/hr Maximum flow in the 1st control stream.
MinFlow2 Mass Flow lbs/hr Minimum flow in the 2nd control stream.
MaxFlow2 Mass Flow lbs/hr Maximum flow in the 2nd control stream.
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Equipment Properties

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Example of using equipment

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Method&Equations

The Steam Header first tallies the inlet and outlet stream flows and sets the state of each outlet. Outlet pressure is the minimum inlet pressure.
The header is not converged if the relative difference between the inlet and outlet flows is greater than 0.0001.
If there is too much steam available, the excess is sent to the sky steam stream.
The header checks the control streams in order. If a control stream flow is less than the minimum or greater than the maximum flow for the stream the control stream flow is set to the minimum or maximum, the header is flagged as not converged and the model aborts.
If both control streams' flow is in range the header model uses linear interpolation to determine the new control flow. Once changed, the header is flagged as not converged, an informative message is issued and the header aborts.

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Warnings

Controller 1/2: Controlled value grater/lower than upper/lower bound !

Controller 1/2: Controller value is not changing !

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Errors

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