General Information

4.1.1. Data Input Window

Double click the required element in the Element tree to display it in the working area.

Select the displayed element with the right mouse button and select Properties from the submenu to open the relevant data input window. The following window relates to the general data of the pipe.

Figure 4-1: Data Input Window

While inputting data, the following options are available:

Apply: The specified data is saved when the error check is valid. The sub-group icon turns green.

Accept: The specified data is saved but no error check is executed and/or

insufficient data is accepted by the user after a warning dialog. The sub-group icon turns yellow.

Reset: Returns to the previous applied settings.

Revert: Returns to the default settings.

Help: Online help is available.

OK: Confirms data input completion and exits the element.

Cancel: Modified data input is not saved. This also exits the element.

If all required data for the element is applied and/or accepted, the red exclamation point disappears, indicating that the input process for that element is completed.

If any input data is missing after selecting apply or accept, a window appears with a list of the missing data and a red exclamation point is displayed on the element. However, the user should be aware that incomplete or incorrect data usually renders a calculation of the data set impossible.

After confirming the element input data, the calculation model must be stored in a file with the extension .BWF by selecting File⏐Save as.

4.1.1.1. Sub-group Icons

The Sub-group icons inform the user as to their status as follows:

Green Sub-group Icon: Valid data has been specified.

White Sub-group Icon: Data has not yet been specified.

Grey Sub-group Icon: Disabled.

Red Sub-group Icon: Insufficient data.

Yellow Sub-group Icon: Insufficient data has been accepted by the user.

Select a Sub-group icon with the right mouse button to access the following options:

Expand or displays all available items in a folder.

Collapse or closes a folder.

Show All displays the complete list of items in the tree.

Show Enabled Only displays the available green and white sub-group icons.

Show Invalid Only displays the gray sub-group icons.

4.1.2. Table Window

Depending on the selected sub-group, the user can enter a constant value or a list of values where the Table icon is displayed. The Table window represents a standard window used throughout the program to specify values dependent on a certain parameter.

As shown in Figure 4-2, select the Table icon and select Table from the submenu. Then select the Table button which appears on the input field to open the following window.

Figure 4-2: Table Window

Select Insert Row to add a line and enter the relevant values. Select Remove Row to delete a selected line.

New or existing parameters can be inserted in the table by clicking on the active field with the right mouse button and selecting the required option from the submenu. Refer to section 2.2.1 for further information.

Large data arrays can be read from an external file by selecting Load. If the data has been specified in the pre-processor, it may be saved in an external file by selecting Store. These files have the default extension .dat. It is ASCII format with one pair of data in each record. The values are separated by one or more blanks. No heading lines are allowed.

If data is defined versus time, the total time interval for which the values are specified may be less than, equal to or greater than the cycle duration. If the time interval is shorter than the specified maximum calculation period, BOOST treats the specified function as a periodic function.

Figure 4-3: Graph Context Menu

4.1.3. Initialization

The initial or boundary conditions can be defined with either Local Initialization or Global Initialization. In the case of Global Initialization the parameters are taken from one of the predefined sets that can be selected with the Preference drop down menu.

Predefined initialization sets can be defined in the Globals section (See

Simulation->Control->Initialization sub tree item).

Preference

For Global Initialization all the parameters are taken from the selected predefined set, no other input is required. For Local Initialization this is optional but if selected can be used as a starting point for the required parameters. These can then be set individually be editing the appropriate number.

Pressure ... Initial/Boundary gas pressure Gas Temperature ... Initial/Boundary gas temperature.

Fuel Vapor ... Initial/Boundary fuel vapor fraction.

Combustion Products … Initial/Boundary combustion product fraction.

Ratio Type ... Defines the units (or type) for the Ratio Value It can be either:

A/F - Ratio : (Air Fuel Ratio) Air Equivalence Ratio Excess Air Ratio

Ratio Value ... Initial/Boundary value which determines the burned fuel fraction in the combustion products.

For initialization of pipes the values can be given as function of pipe location while the Boundary Conditions (System/Internal Boundary) can be specified as function of time.

4.1.4. Flow Coefficients

The following table may be used to determine flow coefficients for well manufactured pipe attachments. Values between the specified points can be obtained by linear interpolation.