Re: [TRNSYS-users] TRNSYS input file (***.air)

The first number is a laminar flow coefficient.
You can look in the CONTAM documentation for details related to this value.
There is also a LaminarCoef.zip file available in the files section of the Yahoo CONTAM user group that provides the calculation method.
Suffice it to say it is utilized when flows are very low in order to prevent undefined derivatives dF/dP, required for solving the non-linear airflow equations, when pressure difference across flow paths approach zero.

Also, there is a new Type98 that utilizes the full capabilities of the CONTAM simulation engine.
Type98 and associated utilities are available on the NIST CONTAM website.

- Stuart

From: David BRADLEY [mailto:d.bradley@tess-inc.com]
Sent: Wednesday, October 15, 2014 10:01 AM
To: Remon Lapisa; TRNSYS users mailing list at OneBuilding.org
Subject: Re: [TRNSYS-users] TRNSYS input file (***.air)

Remon,
The second number is the flow coefficient and the third number is the flow exponent in the equation that relates the flow through the opening to the pressure difference across the opening. I am not sure what the first value is or how it is computed.
Kind regards,
David

On 10/15/2014 01:06, Remon Lapisa wrote:

Hi everyone,

In the TRNSYS input file of Contam (***.air) we will find some 'flow elements' datas, consisting of 3 values numbers on each line, like the example below (for 5 flow elements):

....
-999 wind pressure profiles:
1 2 5
0 -1 -0.00625 6.94444e-005 0
90 -1 0.00625 6.94444e-005 -5.14403e-007
180 -0.25 0.00625 -6.94444e-005 0
270 -0.25 -0.00625 -6.94444e-005 5.14403e-007
360 -1 0 0 0
...etc
-999 flow elements:
1 0.0321663 0.94 0.5
2 0.090255 1.87 0.5
3 0.25528 3.74 0.5
4 0.723488 7.49 0.5
5 0.0176262 1.08102 0.5
.... etc

In the example above, what values are represented by the 3 bold numbers (0.0176262, 1.08102, 0.5) ??

How to calculate the value of 0.0176262 ?

Thank for the help

remon
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