Can I plot Energy & Hydraulic Grade Lines?
Can I plot Energy & Hydraulic Grade Lines?
Yes. FluidFlow allows you to plot Energy & Hydraulic Grade Lines for your system. These graphs provide a clear visual representation of energy levels throughout your system, helping engineers quickly identify potential problem areas.
For more information, see Energy & Hydraulic Grade Lines (EGL/HGL): Advanced System Analysis in FluidFlow.
Can I plot Composite Pump Curves?
Can I plot Composite Pump Curves?
Yes. FluidFlow enables you to generate composite pump capacity curves for pumps configured in series or parallel arrangements. This capability provides an effective visualization tool for communicating system design specifications and pump performance characteristics. For detailed instructions, refer to Composite Pump Curves in FluidFlow: Visualizing Series & Parallel Pump Performance for Optimal System Design.
Can a system curve in FluidFlow show a negative static head?
Can a system curve in FluidFlow show a negative static head?
Yes. A negative static head in a pump system curve can occur under certain conditions:
When it happens:
When the design inlet/outlet pressures would cause flow without a pump
When gravity effects alone would create flow through the system
What it means:
The system resistance curve starts at a negative value on the head (y) axis
The curve will intersect the flow (x) axis, showing the flow rate that would occur naturally without a pump
Calculating Negative Static Head
Static head = Discharge Point Elevation - (Supply Tank Elevation + Liquid Level)
For example, if:
Supply tank elevation: 14.0 m
Liquid level in tank: 1.0 m
Outlet point elevation: 10.0 m
Then: Static head = 10 - (14 + 1) = -5.0 m fluid
This -5.0 m represents the starting point on the head axis of the system curve.
Important Notes:
FluidFlow correctly models these systems, displaying:
The natural flow rate without a pump (where the system curve intersects the x-axis)—approximately 16 m³/h in this example
The increased flow rate when a pump is incorporated into the system (e.g., 39 m³/h)
Understanding static head components:
Total static head: Difference in elevation between discharge and suction liquid levels
Static discharge head: Difference between discharge liquid level and pump centerline
Static suction head: Difference between suction liquid level and pump centerline
Negative suction head is often called "static suction lift"
Remember to account for any non-atmospheric pressures at either end of the system
Why am I encountering the "Solid Phase Detected" warning despite operating above the mixture's freezing point?
Why am I encountering the "Solid Phase Detected" warning despite operating above the mixture's freezing point?
When modeling a mixture by combining fluids in FluidFlow (such as ethylene glycol and water), it's important to understand that the software doesn't account for chemical changes resulting from mixing. Instead, it estimates physical properties for the component fluids individually and solves accordingly.
For example, if you're modeling an ethylene glycol/water mixture at temperatures below 0°C (water's freezing point), you may receive a "Solid Phase Detected" warning. This occurs because FluidFlow identifies that the water component would be solid at that temperature, even though the actual mixture remains liquid due to the ethylene glycol's anti-freezing properties.
This limitation applies to all fluid mixtures in FluidFlow—the software cannot predict the emergent properties of chemical combinations (such as mixing hydrogen chloride and water to form hydrochloric acid). Each component is analyzed based solely on its individual properties.
For best results, obtain the physical properties of the actual mixture using a process simulator first, then define this mixture as a Pure Newtonian fluid in FluidFlow.
Why do I get a "Possibly non-Settling slurry" message?
Why do I get a "Possibly non-Settling slurry" message?
FluidFlow displays this warning when either the calculated d50 particle size based on your defined Particle Size Distribution (PSD) or the d50 input data is less than 75 microns (0.075 mm). This reference value is used in technical literature as a guide for determining slurry flow characteristics. When particles are this small, the slurry likely behaves as a homogeneous suspension rather than a settling slurry.
The warning helps you verify if your slurry model needs to be approached differently.
For particles smaller than 40-75 microns, particles tend to remain suspended in the carrier fluid.
You can confirm this by checking the Rosin-Rammler graph plot on the Chart tab for your inlet boundary.
For more accurate modeling, consider:
Obtaining reliable rheology data for your specific slurry
Checking actual operating conditions
Cross-referencing your slurry characteristics using flow regime boundary charts such as shown below:
Verifying particle size and specific gravity information
Are there warnings about control valve position limits in FluidFlow?
Are there warnings about control valve position limits in FluidFlow?
Yes. FluidFlow has two layers of valve position warnings:
Database Limits Warning: A warning appears when the calculated valve position is below the minimum or above the maximum limit set in the Database. For example, if a valve's Min Limit is 15% and Max Limit is 100%, the software will warn when the valve opens less than 15% or fully opens at 100%.
Good Practice Limits Warning: Found under Options | Warnings & Hints with separate tabs for Liquid, Gas, and Two-Phase Limits. Even if a valve position satisfies Database limits, it will trigger a warning if it falls outside the good practice ranges (typically 20%-75% for liquid systems).
Modeling Tips:
You can apply engineering judgment to accept or ignore these warnings based on your specific system requirements
These warnings help you develop more efficient and reliable designs
Different limits may apply for liquid, gas, and two-phase systems
Consider valve authority when sizing control valves to ensure they operate in the optimal range
How can I list nodes by unique names?
How can I list nodes by unique names?
To list nodes by unique name, navigate to the List tab in the Data Palette, right-click, and select "Show Unique Name." This will display nodes by their Unique Name rather than the default naming convention.
How can I improve the resolution of my flowsheet when exported to Excel?
How can I improve the resolution of my flowsheet when exported to Excel?
To export your model to Excel with high resolution:
1. Set the zoom level: Ensure your Flowsheet zoom is at least 80% in FluidFlow.
2. Export to Excel: Go to File > Excel > Write to Excel.
3. View your export: Excel will automatically launch with your model data. Click the Flowsheet tab to view your model.
Important: Using a zoom level below 80% will result in lower resolution in the exported Excel file.