EBSILON®Professional Online Documentation
Compositions can be specified via boundary values and start values respectively (Component 1 and 33 respectively) or via measured values (Component 46).
The specification via measured values is required only when a validation (data reconciliation) of the composition needs to be carried out.
The thermal properties to be used can be set on a model-wide basis. As a rule these properties can be overridden with components 1 and 33. E. g. the formulation of the gas table to be used can be set in the model options for all streams of the model. Otherwise the formulation of the gas table can be changed for one of the fluids of the model. Example: You can use the formulation FDBR for air and flue gas streams, but "VDI 4670" for natural gas used as a fuel.
When the complete composition is specified via a boundary and start value, it is checked immediately whether the total of all substances results in 1. If that is not the case, an error message will be generated.
When specifying via measured values, one measured value is to be placed on the line for each occurring substance. In addition, one boundary and start value respectively is required on the same line in order to provide the additional information that cannot be defined via measured values (e.g. the coal type or cp coefficients for the user-defined fluid). In this start value one also needs to specify that when integrating the material equations into the equation matrix, equations with the value 0 are provided for the unspecified substances (otherwise one would have to set a measured value with the value 0 for each substance that is not contained).
See specification combo box (left side: property sheet "start value"): for example, only material-integration-mode: set unspecified to zero (16)
If the total of all measured values does not result in 1, an error message will be output.
If you use component 1, switch the stream type (in the ”Ports” tab of the property sheet) to one of the listed stream types.
If you use component 33 or component 46, just place the component on a stream.
Material tables are available for the following stream types:
Open the ”Material Fractions” tab of the property sheet of component 1 or 33.
On the left there is a large field, the info field. A combo box is arranged above this.
The right field is the composition field. The content of the info and composition field depends on the fluid type.
In the profile structure, the composition is inherited like other specification values. But there are some differences:
The button "Load default values" allows loading a predefined composition from the default values database. Below the button, the name of the last loaded composition dataset is displayed.
Input - Combo Box (left side, about information field and composition field): This defines, which of the values defined in this component are used for calculation and which not.
The following selection is possible:
In case of 0 not any fluid values are used for any calculation. In case of 1 all fluid values defined here will be used for any calculation. Cases 2 to 12 define a subset of all values to be used.
Selection from 16 on is only for the use of material equations for simulation or validation in the matrix solution method.
See : EBSILON - Menu: Extras --> Model Options --> Simulation --> Iteration
The input field of the composition is used to specify the composition of your fluid according to the settings mentioned above. If you select a line and click on the number, the field becomes editable and you can type a new value. If one or more lines are selected in this table, the right mouse button offers certain convenient features:
With the universal fluid, the library to be used can also be changed subsequently in the input mask.
See chapter Heating value .