# Data Entry - Known Pressure

With known pressure elements we need to set all properties that define the fluid phase state. In practice this means the rows shown in the Input Editor in Figure 1: Figure 1: General Known Pressure input requirements. Unique Name: Allows you to enter a descriptive name for this element. You can use this to describe the known pressure element. It is not necessary to add any data to this field. If you do enter data here you can use this later to sort via the Lists. Status: For known pressure elements there are 2 possible status values. On; Off. On is the normal position and tells the application that this node is open and to calculate the flow into or out of the element. Off means that this component is closed to flow. You can close known pressures to isolate part of a network. Elevation: This is the height above a selected datum. You can select any datum (base line with elevation = 0) that is convenient for you. When you construct any network you need to decide on a datum. This can typically be ground level, or the centerline of a pump. In flow calculations absolute elevations are not important, only the relative elevations of the nodes are important. The elevation that you enter in this row is the elevation of the known pressure measured from the datum. If you are using this type of node to model a storage tank or any other vessel, you can either enter the liquid height (relative to the datum) directly into the elevation row. As an alternative you can enter the elevation to the base of the vessel then add the liquid height into the pressure field, using units of m Fluid. The end result is the same. Elevation Unit: The unit of length that defines the elevation that you have entered into the elevation row. Pressure Model: This determines if the set pressure refers to stagnation or static pressure. Stagnation pressure is generally used to represent vessels, tanks, reservoirs. To represent a boundary in a pipe, static pressure may be useful, because this is normally the reading from a pressure gauge. Design Note: In FluidFlow, Stagnation Pressure is the sum of the Static and Velocity Pressure. Pressure: This sets the overpressure in the vessel or tank. Atmospheric pressure is a typical value, but the vessel may also be over or under atmospheric pressure. You can also use this field to enter any liquid height that the vessel may contain. For example, if the liquid contains 1 m of liquid and is at atmospheric pressure you can enter a pressure of 1 m Fluid g. If you use this approach then elevation should be measured to the vessel base. Pressure Unit: This is the pressure (or head) unit that you use to define the known pressure. You can use head or pressure units both gauge and absolute. Gauge units end with a "g" and absolute units end with an "a", for example 200 kPa g means 200 KPa above atmospheric pressure. Temperature: This is the temperature of the fluid at the known pressure boundary. Temperature Unit: Refers to the unit of temperature that is used to specify the temperature value. Fluid: You cannot add a value directly into this row by typing an entry. Instead when you focus on this row a button appears at the right edge. This allows you to select a value from the fluids database via the Select Fluid dialog. There are over 1200 fluids in the standard database. Fluid Type: This row may not appear in your version. It only appears if you have the Non-Newtonian/Slurry or Two-Phase module activated. The possible selections are: 1) Newtonian/NN-Non Settling, 2) Heterogeneous Settling, 3) Pulp/Paper Stock and 4) Two Phase. Selecting Newtonian/NN-Non Settling does not require any additional data entry concerning the fluid. You can make Non-Newtonian Non Settling calculations by selecting the appropriate fluid from the Select Fluid dialog. Selecting Heterogeneous Settling means that you can use a settling slurry as the fluid. If you make this selection then the rows as shown in Figure 2 appear: Figure 2: Additional data requirement for a Heterogeneous Settling Slurry Solids: You cannot add a value directly into this row by typing an entry. Instead when you focus on this row a button appears at the right edge. This allows you to select a solid from the solids database via the Select Solid dialog. Concentration Defined By: There are two possible values for this entry: Cw Weight %; Cv Volume %. This row works together with the Solids Concentration % row. If you select Cw Weight % then you can define the solids concentration of a slurry as a weight percent. If you select Cv Volume % then you can define the solids concentration of a slurry as a volume percent. The carrier fluid is defined in the Fluid row. Include Size Distribution: There are two possible states for this entry: Yes; No. If you select No then you will need to enter the d50 and d85 particle sizes. Note that these are the only two particle sizes that are used in the Durand or WASC (Wilson, Addie, Sellgren and Clift) correlations, so even if you enter particle size distribution data it will not be used unless you select the WASP calculation methods. Calculation methods are selected from the Calculation Options Dialog. d50: d50 is the mass mean particle diameter. This is the diameter at which 50% of the sample's mass is composed of smaller particles. d85: d85 is the particle diameter for which 85%, by mass, of the particles are finer. This is therefore the diameter at which 85% of the sample's mass is composed of smaller particles. d50/d85 Size Unit: This entry defines the unit of length used to define the particle size diameters. If you select Yes to Include Size Distribution, then the following rows appear as shown in Figure 3: Figure 3: Additional particle size data required for Include Size Distribution = Yes. % #xxMesh (.yyymm): For each entry, set the solid percent left on the sieve after a sieve analysis. #xx refers to the mesh size and .yyy represents the mesh size in mm. Selecting Two Phase for the row Fluid Type allows you to enter the initial Quality as shown in Figure 4. Figure 4: Additional data required for a Two Phase fluid. Quality (0..1): This is the vapor quality of the two phase mixture at the known pressure boundary. Quality is the mass fraction of vapor in the two phase mix. 0 means that the phase state is liquid and 1 means that the phase state is vapor. This means your entry should be greater than 0 and less than 1. Selecting Pulp/Paper Stock for the row Fluid Type allows you to enter the Wt% Oven Dry Concentration as shown in Figure 5. Figure 5: Additional data required for a Pulp/Paper Stock. Wt% Oven Dry Concentration: This denotes the % composition of pulp/paper stock in the fluid with the remainder being made up of the carrier fluid. Note, the available pulp and paper calculation methods are only recommended for use in the 0.9 to 6 % (Moller) or 2 to 6 % (TAPPI) consistency range. If you wish to model a consistency value outside the noted range values, you may lose accuracy. User-Defined Fields: Allows you to add "fields" to the element, for use in, for example, scripting or reporting. Clicking on the input will display the User-Defined Fields dialog to add/edit/delete fields. Properties On Flowsheet: This value can either be: Show; or Hide. The Properties on Flowsheet row is available for all components. This means that you can decide what properties you wish to show on the flowsheet and for which components. If Show is selected then additional rows appear in the Input Editor, which allow you to set text font, color, size, text position and the properties you wish to display. The additional rows are shown in Figure 6: Figure 6: Additional input data required for showing properties on the flowsheet. Alignment: This row controls the alignment of the component properties on-screen. Possible values are: Top; Bottom; Left; or Right. Alignment of the displayed text is relative to the center of the component. Font: Text font properties can be set from the standard windows font dialog. Properties: Shows/hides Input and Result fields for display of properties on flowsheet. This allows for visibility of any input or calculated/result data to be controlled for each component. Individual property setting is made via the Select Element Properties dialog.