Table of Contents
This is a comprehensive guide on how to use symbolic parameters within BOSfluids, including their definition, management, applications, and how to perform parameter sweeps. By the end of this guide, you will understand how to leverage symbolic parameters to streamline your modeling process and analyze results effectively.
What are Symbolic Parameters?
Symbolic parameters in BOSfluids are placeholders that replace numeric variables with symbolic names. These parameters allow users to define variables in a flexible and reusable way, enabling quick adjustments and linking multiple elements in a model.
Symbolic parameters can be specified in input fields by:
- Right-clicking -> New Parameter -> Entering the symbolic parameter name and its numeric value.
- Typing the symbolic parameter name directly into the input field in the format: [symbolic parameter name] = [numeric value].
Once defined, symbolic parameters can be reused across various input fields, provided the units of the parameter match the input field’s unit. This feature ensures consistency and simplifies model modifications.
How to Manage Symbolic Parameters
To manage symbolic parameters in BOSfluids:
- Navigate to Tools -> Parameters. This menu becomes accessible only after at least one symbolic parameter is created.
- The Parameters Table displays:
- Parameter name
- Field where the parameter is specified
- Current value of the parameter
- Unit of the parameter
While the parameter’s value can be edited directly in this menu, other attributes (e.g., name or field) cannot be modified here. This centralized management system ensures that all symbolic parameters in the model are easily accessible and modifiable.
What is the Use of Symbolic Parameters?
Symbolic parameters offer several advantages in BOSfluids:
- Quick Variable Adjustments: They allow for rapid changes to variables without manually editing multiple fields.
- Parameter Linking: Multiple elements in a model can be linked through a single symbolic parameter, ensuring consistency and reducing errors.
Parameter Sweeping: Symbolic parameters enable parameter sweeps, which are essential for steady-state analyses and fire water coverage studies. This allows users to evaluate system behavior under varying conditions efficiently.
How to Create a Parameter Sweep
Parameter sweeps in BOSfluids are used to analyze the impact of varying symbolic parameters on system performance. Sweeps can only be performed in specific analysis types, such as Steady State and Fire Water Coverage.
Steps to Create a Parameter Sweep:
- Define a Symbolic Parameter: Create a symbolic parameter (e.g., Valve_Opening) and assign it a default value.
- Access the Parameter Schedule Menu: In the analysis tab, double-click on the parameter schedule to configure the sweep.
- Input Sweep Details:
- Select the sweep type (Linear, Multi-Linear, or Custom).
- Define the range of values for the parameter (e.g., initial and final values).
- Specify the number of variations (e.g., 20 data points for a linear sweep).
Once configured, the parameter sweep is ready to run. The results can then be analyzed to understand the system’s response to the parameter variations.
Parameter Sweep Types
BOSfluids supports three types of parameter sweeps:
Linear Sweep
- Description: The parameter value is interpolated linearly between the initial and final values, with data points evenly distributed based on the specified number of variations.
- Use Case: Ideal for single-parameter sweeps where the relationship between variables is expected to be linear.
- Example: Sweeping a valve opening from 5% to 100% in 20 increments.
Multi-Linear Sweep
- Description: Allows for multiple parameters to be swept simultaneously, considering all possible combinations of their variations. This approach provides a comprehensive overview of system behavior but is computationally expensive.
- Use Case: Suitable for analyzing the interaction between multiple parameters.
- Example: Sweeping valve openings (5% to 100%) and outlet pressures (3 barg to 7 barg) simultaneously.
Custom Sweep
- Description: Enables users to define non-linear parameter variations through tabulated data. Custom sweeps allow for precise control over parameter values and can be imported/exported as needed.
- Use Case: Useful for scenarios where parameter variations do not follow a linear or multi-linear pattern.
- Example: Manually specifying valve openings and pressures based on experimental data.
Reviewing Parameter Sweep Results
After completing a parameter sweep, BOSfluids provides tools to analyze and interpret the results effectively:
- Slider Tool: Use the slider to cycle through the variations and view results for each parameter combination.
- Variation Plot: This plot compares the effects of parameter variations on nodal or elemental variables of interest. It provides a clear visualization of how changes in parameters influence system performance.
- 3D Plots: For more detailed analysis, 3D plots can be used to examine the relationship between multiple parameters and their impact on the system.
Example: Reviewing Results for a Linear Sweep
- After running a linear sweep for valve openings (5% to 100%), the variation plot can be used to identify the valve opening that keeps the pump operating at its rated point (e.g., 9463 L/min). By zooming in on the pump curve, the optimal valve opening can be determined (e.g., 85% open for variation 17).
Example: Reviewing Results for a Multi-Linear Sweep
- For a multi-linear sweep involving valve openings and outlet pressures, the variation plot groups results by pressure levels. This grouping helps identify the optimal valve opening for each pressure level (e.g., 85% open at 7 barg).
By following this guide, users can effectively utilize symbolic parameters in BOSfluids to streamline model setup, perform parameter sweeps, and analyze results. These capabilities enable engineers to optimize system performance and gain deeper insights into fluid dynamics behavior.