Ventilation Analysis Data and Congestion Ratio


Once a monitor region has been defined and a ventilation simulation run, you can view the ventilation analysis data.


To open the ventilation analysis window:

Select Ventilation Analysis from the Project menu, or select the  icon on the toolbar, the following window will appear. If a window pops up saying "Some data for the monitor regions is not up to date," click OK, and then click the Update button () in the upper right corner of the window.


Tutorial 3 - Figure 33 - Ventilation Analysis Window showing Air Changes Per Hour for each of the monitor regions.


When performing safety analysis studies, it is often useful to know the Air Changes Per Hour or the Average Velocity across the monitor region. The air changes per hour is calculated by looking at the “volume flux” into the region. The faces of the monitor regions are split up into individual areas. Velocities are then calculated for each of these areas. The volume flux is then the summation of the velocities. Air change is then the volume flux divided by the total volume of the monitor region. The average velocity is simply the average wind speed across the entire monitor region.


The Ventilation Analysis Window provides both of these statistics for each completed ventilation simulation and each monitor region defined.


As with the gas cloud data, you may export the data from this window to excel. The data will have more significant digits than that of the ventilation analysis window.


in:Flux also calculates the congestion ratio of defined monitor regions. This information is seen via the properties panel of the monitor region you want to know the congestion ratio of. Figure 34 below shows us that for our example, the Facility Monitor Region has a congestion ratio of 0.139. For in:Flux the congestion ratio is calculated as the total equipment volume within the monitor region divided by the total volume of the monitor region. The calculation of the congestion ratio takes a couple of seconds so if a value doesn't immediately appear check back after 10 seconds, this will be longer for more complicated geometries.


Tutorial 3 - Figure 34 - Indication of location of the congestion ratio for the Facility Monitor Region.


Note that a value of 1 will exist for the congestion ratio prior to its calculation, meaning if the monitor region has a gray text in the Properties Panel (as in Figure 35 below), the region needs to be updated. This can be done via the gas cloud analysis window or by right-clicking on the name in the project items tab and choosing Regenerate as shown below.


Tutorial 3 - Figure 35 - Context menu for monitor region indicating how to regenerate the data for the congestion ratio and gas cloud analysis data.


This completes Tutorial 3. You should now have an understanding of how to extract data from in:Flux simulations.


Save you working file as it will be used next in Tutorial 4.