Introduction
Once you have built the physical layout of your network, the next critical step is to enter the input data. This process involves defining the specific properties and operating conditions for every component in your model, from fluid characteristics and pipe dimensions to pump performance and valve settings. Accurate data entry ensures your model accurately represents real-world conditions, transforming your schematic into a functional hydraulic model ready for calculation.
This guide provides a comprehensive overview of how to define input parameters for all components in your FluidFlow model, with a special focus on leveraging and expanding the built-in database.
Defining Input Data: A Step-by-Step Guide
Once you've placed and connected components, you may now define their properties using the Input Editor, which appears on the right side of the flowsheet when you select any component.
Figure 1. Input Editor.
Step 1: Define Boundary Conditions
Inlet and outlet boundary conditions are the starting point for data entry, as they establish the fluid, pressure or flow, and temperature for the entire system.
Select an inlet boundary node (e.g., a Known Pressure or Known Flow node).
In the Input Editor, define the following:
Elevation: Enter the node's elevation. This is crucial for accurately calculating static head, especially in liquid systems.
Flow/Pressure: For a Known Flow node, enter the required mass or volume flow. For a Known Pressure node, specify the required pressure.
Fluid Data: Click the
...button to open the Fluid Database. Select your fluid (e.g., Water).Temperature: Specify the fluid temperature.
Step 2: Define Pipe Properties
Pipes are the main source of hydraulic resistance and heat exchange in your system. Accurately defining their physical characteristics is essential for precise pressure loss calculations.
Select a pipe on the flowsheet.
In the Input Editor, define the required properties:
Length: Enter the total pipe length.
Size: For standard sizing, click the
...button to select a pipe size and classification from the database. For custom sizing, specify the inside diameter and wall thickness directly.Friction Model: Choose from Moody, Hazen–Williams, Fixed Friction Factor (Darcy), or Shell-MIT.
Surface Roughness: Use database values for pipe material condition (new, aged, corroded) or enter a custom value if you have specific data on your pipe's condition.
Scaling Factor: Apply database scaling factors (None, Low, Medium, Heavy) or enter custom values based on your system.
Sizing Model: Select whether the pipe will be sized using economic velocity or using specified velocity or pressure gradient criteria.
Heat Loss Model: If heat transfer is being considered, specify the additional required parameters.
Step 3: Define Component Properties
Each component in your system requires specific input parameters.
Select a component (e.g., a pump, valve, or fitting).
In the Input Editor, fill in the required data:
Pumps: Configure pump performance using one of two methods:
Auto-Size Method: Enter the design point parameter. FluidFlow will calculate the required pump head for a specified flow rate or determine the achievable flow for a given pressure rise.
Rated Method: Select a pre-loaded manufacturer's pump curve from the database. When adding new pumps, include the flow vs. head curve, efficiency data (for accurate power calculations), and NPSH requirements (if available).
Manual Valves: Select a valve model from the database. For partially open valves, specify the percent opening.
Control Valves: Specify the control objective—such as Downstream Pressure, Flow Rate, or Differential Pressure that the valve must maintain.
General Resistances: Use these for localized losses not represented by standard components. Select the appropriate node (Inline Filter, K, Kf, Kv, etc.) and enter the corresponding data.
Size Changes: Required data depends on the component type:
Orifices: Enter orifice size if not auto-sized.
Reducers/Expanders: Define the reducer length. Enable "Use Database Length = Yes" for automatic selection of matching reducer/expander.
Junctions: For fittings like elbows and tees, FluidFlow automatically calculates losses based on the selected correlation (Idelchik, Miller, Crane, or SAE).
IMPORTANT: You must enter the elevation for every node in your system to properly account for static pressure changes in the calculations.
Leveraging and Expanding the FluidFlow Database
FluidFlow includes a comprehensive database of fluids, materials, and component data that accelerates model setup and ensures the use of industry-standard values. You can also enhance this database with your own project-specific information.
To access the database manager, go to the Database menu and select the specific database item you wish to view or modify.
Using Pre-loaded Data
For many inputs, you can simply click the ... button to open a window where you can select from pre-populated data in the FluidFlow database. These include:
Fluid Properties: A comprehensive list of common liquids and gases with their physical properties.
Pipe Data: Standardized pipe sizes and classifications.
Component Data: Manufacturer-specific performance data for pumps, valves, and other equipment.
Surface Roughness: Pipe conditions ranging from "Clean or New" to "Heavily Corroded" with corresponding absolute roughness values.
Scaling Conditions: None, Low, Medium, Heavy.
Thermal Data: Insulation and pipe material thermal conductivities.
Solids Data: Physical properties for settling solids.
Adding New Data to the Database
If your project requires a fluid, material, or component not already in the database, you can easily add it. Use the three-dot database button beside a field to open the selector. If the required entry doesn't exist, add it.
Adding New Fluid Properties
When you need to model a fluid not found in the default database, follow these steps to create a new fluid entry:
Navigate to Database | Fluids in the main menu
Click Add to create a new entry
Enter the fluid name and select its type (Pure Newtonian, Non-Newtonian Liquid, Gas, etc.)
Define the fluid properties by either:
Entering tabular data for density, viscosity, specific heat capacity, and vapor pressure at various temperatures
Setting up property correlations as functions of temperature
Verify completion by checking that the appropriate light bulb indicator for the fluid type is lit
Click OK to save the fluid and make it available for all current and future projects
For detailed step-by-step guidance, watch this tutorial.
Adding New Pump Performance Data
Instead of relying on a simple duty point, you can add a complete manufacturer pump curve to the database for more accurate analysis:
Go to Database | Boosters
Select Centrifugal Pump and click Add
Enter a unique name
Input manufacturer and other model information
Input capacity curve data (flow vs. head)
Add efficiency and NPSHr curve data when available
Define operating speed, impeller diameter, and minimum/maximum ranges if applicable
Click OK to save pump data to database
Adding New Control Valve Data
For specific control valves, you can add new manufacturer data to the database:
Access Database | Controllers
Select a specific manufacturer (or Unspecified) and click the Add button
Enter a unique name
Specify necessary control valve parameters (Xt, FL, Fs, and Fd)
Define flow coefficient data (Cv or Kv) and add opening position curves if available
Click OK to save valve specifications
Adding Other Component Data
The database can be extended with many other types of components:
General Resistances: Add as Inline Filter, K, Kf, or Kv
Size Changes: Add length and max large connection size
Sprinklers: Add by Nominal K or flow vs. pressure loss table
Solids: Add solids material and its physical properties
Insulation Materials: Add insulation materials with thermal conductivity
Pipe Thermal Conductivity: Update values for heat transfer calculations
Pipe Roughness: Add surface conditions and absolute roughness values
Pipe Scaling: Use database presets or add specific values
Manufacturers, Materials, Applications: These fields are database-controlled lists. Update the relevant database if a manufacturer/material/application is missing.
Advanced Input Features
Multi-Component Selection
For efficiency when entering similar data across multiple components:
Hold Shift and click multiple similar components
Changes made in the Input Editor apply to all selected items
Useful for setting common pipe specifications, elevations, or fluid types
Copy and Paste Properties
To quickly duplicate properties across similar components:
Right-click on a component with defined properties
Select Copy Inputs
Right-click on target components and select Paste Inputs
Choose which input properties to paste and click OK
Best Practices
Start with boundaries: Define inlet and outlet conditions before component properties. This establishes the fluid, pressure, and temperature for the entire system.
Use database values: Leverage FluidFlow's extensive database for standard components.
Verify units: Ensure all inputs use consistent unit systems. Be mindful of Cv (US) vs. Kv (metric), pressure (gauge vs. absolute), and temperature scales.
Document custom data: Keep records of any custom database additions.
Check property ranges: Ensure fluid properties are valid for operating conditions. Enter realistic temperatures, as fluid properties depend strongly on temperature.
Review elevation data: Verify all elevation inputs are consistent and accurate.
Keep friction models consistent: Only mix friction models when absolutely necessary; maintain consistency throughout networks when possible.
Use multi-select: Apply common properties (e.g., elevation or pipe size) to multiple components simultaneously for efficiency.
Verify directional components: Ensure that discharge pipes for pumps and check valves, as well as branch pipes for tees, are correctly defined.
Run quick tests: After defining inputs, run a quick calculation and address any warnings immediately.
Common Input Errors to Avoid
Missing boundary conditions: Ensure every flow path has defined inlet/outlet conditions.
Inconsistent units: Avoid mixing imperial and metric units within the same model to avoid confusion.
Unrealistic property values: Always validate custom inputs against engineering judgment.
Incomplete pipe data: Ensure all pipes have length, size, and material specifications.
Wrong fluid selection: Verify fluid properties match actual system conditions.
Unrealistic pipe lengths: Check that pipe lengths are equal to or greater than the difference in node elevations.
FAQs
Q: How do I know if my input data is complete?
A: FluidFlow visually highlights nodes with incomplete data and displays errors or warnings when you attempt calculations.
Q: My fluid isn't in the library. What can I do?
A: For custom fluids, if a fluid you've added to the database doesn't appear in the selection window when using the Input Editor, this indicates incomplete fluid data. Ensure you have defined all required physical properties and that the light bulb indicator is lit before using the fluid in the model.
Q: Can I create custom fluid mixtures?
A: Yes, FluidFlow allows you to create custom fluid mixtures either by Database Mixing or Flowsheet Mixing.
Q: Where do I set pipe roughness and scaling?
A: In the pipe's Input Editor. Select roughness and scaling from the database or specify custom values.
Q: What's the difference between a Known Pressure and a Known Flow boundary?
A: A Known Pressure boundary sets a fixed pressure at a specific point in the system (like a tank open to atmosphere), and FluidFlow calculates the resulting flow rate. A Known Flow boundary sets a fixed flow rate entering or leaving the system (such as supply or demand specifications), and FluidFlow calculates the pressure required to achieve this flow.
Q: Why can't I type directly into the Manufacturer/Material/Application fields?
A: These fields use database-controlled lists. Click the three-dot button to select existing items or add new ones, or update their respective databases in the Database menu.
Q: Can I import component data from external sources?
A: Yes, FluidFlow supports importing data from CSV files, enabling faster and more accurate creation of custom database entries.
Additional Resources
For specialized components and advanced database customization, refer to these additional resources:
Conclusion
Entering input data transforms your diagram into a functional model. By methodically defining each pipe and component's properties and utilizing FluidFlow's extensive database, you establish the foundation for accurate system analysis.
FluidFlow's comprehensive database, combined with the ability to add custom data, enables you to model virtually any hydraulic system. By following the steps to define properties, using the database effectively, and applying best practices, you'll build models with reliable input that produce dependable results.
Accurate input data is key to creating a useful hydraulic model, transforming a simple drawing into a powerful predictive tool for design, analysis, and troubleshooting.