Simulation start error (checked and not found)

[Nabil Mhmoud]

Hello,

attached he FDS file of a parking simulation for jet fans, when i try to run the simuation i keep having an error that vent is not attached to solid obst. 

when i checked he vent and the obst. dimensions and locations i found that they are attached to each other, pls help me understand the source of this error

attached the FDS file

Thnx

[Kevin McGrattan]

This is what PyroSim should do for you. Why are all these obstructions INVISIBLE?

&OBST ID='AcDbBlockReference - 15C8 [Faces]', XB=1.4,1.6,-58.8,-58.6,0.0,0.0, COLOR='INVISIBLE', SURF_ID='Global05'/

This certainly does not help us find the problem. Maybe you should rethink why you need 4000+ obstructions.

[Nabil Mhmoud]

Hello Kevin,

the invisible obst were he CAD i imported to build my model on it, it is of no use in the simulation

i have deleted it and re tried running the simulation but with no luck

the other obstructions are the cars, i have also tried to disable them and rerun but same result, pls advise why i keep having vent. is not attached to solid obst. although all vents are attached properly to solid surfaces

i have attached the updated fds (after deleting the dwg import & disabling the cars obst.) and also the psm which is well orgnized for your kind support

thnx

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[Nabil Mhmoud]

furthermore, i have tried reducing mesh size to 10 cm instead of 20cm but same error (floor volume 11400 cubic meter)

do you think maybe an instability generated this error since i,m using 18 jet fans each having 2 ducts & 3 nodes, if thats the case wil it help if i made the jet fan obst. having 2 surfaces one supply & one exh. for simplification?

[Kevin McGrattan]

For me to help you, you have to eliminate all OBSTs and VENTs except the ones causing trouble. Otherwise, I cannot find this needle in a haystack.

[Nabil Mhmoud]

Dear Kevin,

thank you for your quick response, I have deleted all unused obst. & vents

please find attached the updated psm & fds file for yur kind support

Thank you

On Sun, Jan 30, 2022 at 2:29 AM Kevin McGrattan <mcgr...@gmail.com> wrote:

For me to help you, you have to eliminate all OBSTs and VENTs except the ones causing trouble. Otherwise, I cannot find this needle in a haystack.

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[Kevin McGrattan]

You misunderstood. I want you to eliminate all VENTs, OBSTs, and other input lines that are not near the VENT that is identified as being away from an OBST.

[fde]

@Nabil Mhmoud

If you diagnose the error, it says VENT #40 must be on solid obstructions. I counted the VENTs in the fds file and the first error indicated the last VENT in the fds file (40th VENT). I noticed the VENT is applied to until 3.4 m height but attached solid has 3.0  height. When I updated the VENT height to 3.0, the error disappeared. However it seems this error is present on more than one VENT. So you need to check and fix all. 

May I ask why you use two Ducts and Fans for each jet fan? You could have used one only. 

[Kevin McGrattan]

This is something that PyroSim should do.

[Nabil Mhmoud]

Hello yilmaz,

Thank you for your reply, i will double check on the vents heights thoroughly.

As for the 2 ducts i used that to simulate the low and high speed activation of the jet fans at which will be linked to the activation trigger of a heat or smoke detector soon after fire starts emitting noticable HRR.

I will update the fule and share it's status with you.

Regards

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[Nabil Mhmoud]

After checking vents height, especially at corners of the parking,,

Simulation is now running, turned out the makeup and exhaust vents on the parking corners were higher than their related obstruction. Now simulation running normally

Thnx all