Problem In temperature profile

[harekrishna123@gmail.com]

I am trying to simulate a fire inside an enclosure..

Fuel- N-Heptane and 100 ml quantity (can anyone suggest how to set these fuel ppts in pyrosim?)

I want know how to get HRR for N-Heptane?

suggest some reson why the temp just above the pan is fluctuating a lot?

I have attached the files ..

Thanx..

suri

[FrkStorm]

I suggest you read this paper on errors in thermocouple measurements: http://ams.confex.com/ams/pdfpapers/67056.pdf

If a fire is modeled properly within FDS there is a possibility of fluctuating temperature gauging - even in a simulation.

If you are looking for a steady state model I suggest something like Sofie instead.

[harekrishna123@gmail.com]

Haii..Everybody can som1 help me regarding number of cells that I can use for meshing of an enclosure..

My enclosure size is 1 m x 1 m x 1 m:

I have played with Pyrosim by giving a lot of numbers as number of cells.

But for some numbers it gives some errors like VENT 3 IS NOT ATTACHED TO A SOLID OBSTRUCTION...

And for some other numbers it works properly...

Can anyone suggest how to decide number of cells??

Suri   

[Charlie Thornton]

Consider the following model:

(For simplicity, I'll discuss only one coordinate axis.)

1. A mesh with Y=[0.0 - 1.0] and divisions every 0.1 (i.e. 10 cells in the Y direction)

2. A solid obstruction with Y=[0.5 - 0.54].

3. A vent with Y=0.54

Everything appears fine because the vent lies on a solid obstruction. However, when FDS runs, objects that are small relative to the mesh may be reduced to "thin" obstructions. In this case, FDS will reduce the previously solid obstruction to a thin obstruction with Y=0.5. The vent will also "snap" to the coordinate Y=0.5.

In this situation, the vent is still located on the side of the correct solid object, but since the object was reduced to a thin obstruction it can no longer host the vent. FDS will then issue the error message you saw.

This is the most common cause of "VENT n IS NOT ATTACHED TO A SOLID OBSTRUCTION". If it doesn't fit your situation, we'll probably need to look at your model to tell you more.

[harekrishna123@gmail.com]

Thank you so much CHARLIE..

Please can you help me on how to GET A CORRECT VALUE OF HRR (Heat Release Rate)

for a particular fuel/condition? (i.e n-Heptane)

On what factors does it(HRR) depend?