Friday Flownex Tech Tips #11

How to use Flow Path Graphs and Increment Plots in Flownex

Flow Path Graphs and Increment Plots can be incredibly useful visualization tools to see how a simulation result varies as a function of length along the axial flow path and to see a higher fidelity result for a single flow component. Use these in Flownex to up your reporting game! In this demo we are using Flownex version 8.12.7.4334

Creating a Flow Path

A flow path is any continuous series of flow elements and can be created by clicking “Flow Paths” in the results ribbon. Once we’ve created our new flow path we define it by choosing our start and end nodes.

Another, simpler, method is to simply drag and drop the nodes onto the flow path start and end point:

If we have a branched network we can add an intermediate node or flow component to our flow path to ensure the correct path is captured in the graph:

Insert a Flow Path Graph

The Flow Path Graph is in the component pane under visualization > graphs. Once the graph is added to the canvas we simply need to drag and drop our newly created flow path onto the graph and choose the characteristic we are interested in plotting. We will need to drag and drop the flow path for each characteristic we would like plotted.

How to create Increment Plots

You may have noticed in the previous images that there were many data points on the graphs for each of our flow components. This is because we had each pipe modeled as 25 increments. When we add increments to our flow components Flownex will treat each component as if it were split up that number of increments – solving the conservation equations for each increment rather than once over the entire component. This is helpful when modeling long pipes, capturing pressure waves, or determining exactly where a phase change may happen. A good way to think about this is that it is essentially the same as refining a mesh in a typical finite element analysis.

There is another plot in Flownex we can use for a single flow component that has been incremented. The increment plot is located in the components pane under Visualization > Graphs > Increment Plots. If we were, for example, trying to plot the inside surface temperature of our first pipe in this example network we could use an increment plot to see what is going on.

To create an increment plot we simply drag and drop the plot onto the canvas. We can either selectively drag results from individual increments or multi-select many increments and drag the desired variable onto the graph. Note that since there is a tie of each increment parameter separately there may be some delay if we are multiselecting a very large number of increments.

Bonus Tips!

  • We can use a Flow Path graph for a single component to avoid having to multi-select increments.
  • To create a graph on its own page instead of floating on the canvas go to the Project Explorer pane on the left side of the GUI, select Graphs, then right-click on the Graphs Folder and select Add Graph Page and choose your desired type of plot.

Friday Flownex Tech Tips #7

Using Views to bridge networks across multiple pages

When building our networks it may be necessary to utilize multiple pages for a single network. This could be simply because our network is large and complex, or because it simply makes sense to keep certain branches or processes separate. In this tech tip we will show how to use “views” to continue networks across multiple pages. For this example we are using Flownex version 8.12.7.4334.

Views

In Flownex the way that we continue networks across pages or even just jumping across portions of the same page is through the use of “views”. To create a view we right-click on the component we’d like to use as our bridge and select copy. Then navigate to where we’d like to continue our network and right-click, “paste view”.

Note that this is not really a “copy” of the previous node; it is another instance of the exact same node. I personally recommend using nodes for views over flow components so that they are less likely to be mistaken as separate components.

Regarding views

A couple of things to note regarding view components. First, you’ll notice the floating “V” to the left of the component. This indicates that the component is a view. It’s a good idea to leave this layer on – if for some reason you cannot see the “V” it can be turned on under the view ribbon:

Secondly, to find out where the views are located in your network the simplest way to jump between them is to right-click on an existing view and select the “views” option. Here you can navigate to any other views by simply clicking on them. Note that you are not limited to only two instances of a node (two views). There could be many instances across many pages.

Common uses of views could be to connect networks built by different engineers, connecting different subsystems that make up a larger network, or even capturing 3D network layouts by building a portion of the network in the x-y plane and using a view to connect to part of the network built in the z-y plane.

Friday Flownex Tech Tips #6

Creating Custom Fluids

Occasionally glossed over, adding custom fluids is a fairly standard operation in Flownex that we don’t think about until it’s necessary. There are a couple of ways to do this which we’ll go over in today’s post. I am working in Flownex 8.12.7.4334.

Creating a mixed fluid

To create a mixed fluid we first need to create a folder for this fluid in our project database. This can be done in the charts and lookup tables pane by right clicking on “mixed fluids” and selecting “add category”. We can create our new fluid by right-clicking on the new folder and selecting “Add a new mixed fluid”. Note we can right-click and rename both the fluid itself and the containing folder.

To define our new mixed fluid we double-click on the new mixed fluid to open the editor. Here we can add the components of our mixed fluids.

Creating a new fluid from scratch

To create a fluid from scratch we repeat the same process of creating a folder and creating a new fluid as above with the exception being that we’d complete these steps under the “Pure Fluids” category. Once this is done we’ll need to double-click or right-click > edit our from scratch fluid and enter in the fluid properties. Note for many properties we can define the relationship with pressure and temperature as constant (non-dependent), table, equation, or script.

Importing a fluid

To import a fluid we will follow the same steps of creating the folder under pure fluids. Now instead of right-clicking and adding new we will right-click and select “import”. Then we simply navigate to our desired fluid file and click “Ok”.

Bonus Tips!

  • In the window where you define your fluid you’ll notice the “Test” button. This feature can be utilized to test created fluids to confirm properties against known properties for given pressures and temperatures.
  • We can also copy and paste fluids from the master database into the project database to give us a good starting point for creating similar fluids (or extending properties to higher/lower temps/pressures).

Friday Flownex Tech Tips #3

Input Sheet Hacks!

Building on last week’s global parameters example I’d like to show some tricks within the input sheet environment. These are really more so excel tricks – but the methodology within Flownex is slightly different. In this example I am working in Flownex Version 8.12.7.4334

Refresher on using Input Sheets

To create a new Input Sheet we will navigate to the project tab, then select “Excel Reports/Pages”, right-click on the Input Sheets folder, and select “New Input Sheet”

To add inputs to the sheet it’s as simple as dragging and dropping the inputs from the component into the desired cell in the Input Sheet.

Formatting our Input Sheet

I like to use color, shading, and border to specify which cells contain inputs so that if I pass the project off to a client or colleague it is immediately clear what variables they should be editing and which cells they shouldn’t change.

To modify the formatting we need to enter “workbook designer”. This is done by right-clicking on the input sheet and selecting “workbook designer”

All of the standard Excel-type formatting is available here, including adding graphs, images, etc. Typical operations are found in the format menu on the top ribbon.

Drop Downs

A more advanced Excel operation I like to integrate into these types of input sheets is a drop-down where multiple inputs may be tied to a given condition. In the example below I set up a scenario for given ambient temperature for cold day, hot day, and nominal day.

In the workbook designer we will click “insert” > “worksheet” and build our list of environmental conditions. On the right we will set the associated temperatures.

Back on Sheet1 we will need to set up the data validation cell reference to this table. Select the cell where we want to add the dropdown and go to data > validation. We will choose list, and reference cells B2:B4 of Sheet2.

We will need to use VLOOKUP to associate the temp to another cell based on this dropdown. Where this becomes valuable is when we have many input variables tied to each of the dropdown selections.

In this example, since we’ve put the applicable temps a single column to the right the syntax for VLOOKUP will be “=VLOOKUP(B5,Sheet2!B2:C4,2,FALSE)”. After this is added it should behave as follows:

As I mentioned before, this trick becomes very powerful when you have many different environmental or operational inputs tied to a single “scenario” that you want to model in an individual run rather than in a parameter study.

Bonus Tip!

  • All of these tricks can be applied to any of the excel-type sheets within Flownex. Remember to be careful with parameter tables as the inputs and results are tied to the columns instead of individual cells.