ValveEdge

Description

The component ValveEdge is a model of a flow resistance that behaves either as an orifice or a throttle, depending on the parameter setting.

Flow is adjusted proportional to the Input signal starting from Minimum value of the input for look-up table with nominal flow (as given by nominal flow/nominal pressure difference) corresponding to an input value of InputMax. Unlike the Resistor component, the look-up table for valveEdge is declared for the input range from -1 to 1.

Input is shifted by Offset with within +/- 1. In accordance with common valve parameters a negative offset will open the valve edge.

Leakage is specified by Volume flow due to leakage/Pressure difference for leakage flow, this flow is permanent and the overall flow of the valve edge is calculated as max(Nominal volume flow, Volume flow due to leakage).

The default relationship between input signal and flow rate of the resistor is linear, but can be changed through the use of a 1D look-up table. The look-up table is provided either manually or by importing a text file. If the parameter Table is provided by file is set to false, the manually entered datapoints from Manually provided look-up table will be used. If it is set to true, the table Table name on file from the file File where look-up table is stored will be utilized.

The text file must follow a specific syntax such that it can be read by Modelica. The input values as well as the output values must lie within the range from 0 to 1. An output value of 1 (100 %) corresponds to a fully-opened resistor. An example for a properly formatted text file with two tables is given in the figure below:

A table is declared by its datatype (e. g. double), followed by the table name (e. g. tab1) and its dimensions in brackets (e. g. (5,2)). As can be seen, multiple tables can be defined in the same text file. The table declaration is followed by the actual data. The first column of the table represents the input of the 1D table, whereas the second column lists the corresponding output values. The input values of the table must be in increasing order. The component interpolates linearly between the listed input values. More information regarding the format of tables can be found at CombiTable1D.