Questions on new CFAST 7.6.0 functionalities

[Burkhard]

Hi,

I went through CFAST 7.6.0 and found some interesting changes to older versions where I could not find any documentation in PDFs or the release notes. Please could you give some information?

1.      Could you explain for the WALL leakage function if the leakage is considered in the upper or lower layer or depends from layer height?

I believe for the FLOOR leakage it is in the lower layer anyway.

2.      In CEdit, "compartments"-window, regarding the “FLOW CHARCTERISTIC” “SHAFT”, the expression in brackets changed: In 7.6.0 it is “SHAFT (double-zone model)” and used to be “SHAFT (single-zone model)”. Could you explain?

3.      With the V-option activated the masses.csv file includes “Potential” species. Could you comment when these will be produced?

Thank you and best regards
Burkhard

[Richard Peacock]

1. The wall leakage just creates a wall vent with a height that goes from 5% of the ceiling height to 95% of the ceiling height.  The width of the vent then calculated from that height and the requested leakage area. Flow is then calculated as with any other wall vent, including flow to/from the layers in the compartment where the leakage is specified.  For floor leakage, we create two vents, one at the ceiling and one at the floor, each with 1/2 the specified leakage area (with the vent width covering 90% of the width of the shortest wall. Again, it's then calculated the same as any other wall vent.

2. The "double" was an editing error on my part, it should say "single" as before. There was no change in the calculations, just the label.

3. The "Potential" species is used to keep track of unburned species just like we did previously for unburned fuel. It allows a better calculation of door jet fires to ensure proper mass balances for species when there is more than one fire in a simulation.