[fds-smv] Radiation measurement

[clem...@tpi.setec.fr]

Hi,

I have a few question about the sensor "RADIATIVE HEAT FLUX GAS" and
"INTEGRATED INTENSITY".

Of what I understand in the User guide, the only difference between
this two is that the former integrates the incoming radiative flux
over 2pi solid angles around the vector defined by ORIENTATION. And
the latter integrated the incoming radiative flux over 4pi solid
angle.

Both don't take in account the absorption coefficient of the cell (if
there is a lot of suit in the cell, or if there is human skin do no
difference for this quantity)

Am I right ?

Thanks for your help !

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[Kevin]

Vous n'avez pas raison. 'RAD HEAT FLUX GAS' est comme une radiometer
que vous n'aves pas situé sur la surface solide. 'INTEGRATED
INTENSITY' n'a pas la même definition. Il est difficile pour moi
d'expliqué, même si je parle anglais. Lisez le <<Technical Reference
Guide>>, Radiation chapitre.

On Apr 16, 5:19 am, "clemen...@tpi.setec.fr" <clemen...@tpi.setec.fr>
wrote:

[clem...@tpi.setec.fr]

Hi!
Could you answer me in English Kevin, if you don't, nobody else will
help me because they won't understand what we are talking about.
Thanks.

> Vous n'avez pas raison. 'RAD HEAT FLUX GAS' est comme une radiometer
> que vous n'aves pas situé sur la surface solide.

RADIATIVE HEAT FLUX GAS : Works like a radiometer and it integrates

the incoming radiative flux over 2pi solid angles around the vector

defined by ORIENTATION. It is NOT attached to a solid surface.

INTEGRATED INTENSITY: integrates the incoming radiative flux over 4pi
solid angle. It is not attached to a solid surface.

Are my definitions right ?
If yes, the only difference between this two 'sensors' is the 2pi or 4
pi angle solid ?
If no, could you try to exlpain me what is the difference between
Integrated intensity and radiative heat flux gas ?
It don't matter if I you think I won't understand, try it if you can !

Thanks a lot !

[Kevin]

Wow -- this is probably the first time in history that a French person
has asked that English be spoken! OK, I write in French to practice. I
studied French for 6 years in high school but rarely have a chance to
practice. I have friends from France (Maison Lafitte, near Paris)
coming in a few weeks, so I must get ready.

The ambient value of integrated intensity is 4*sigma*T^4=1.67 kW/m2 at
ambient temperature (T=293 K). The 4 is related to the 4 pi solid
angles of the integration, but there is a pi in the denominator
somewhere. The source term definitions are confusing. In any case, we
use 'INTEGRATED INTENSITY' for diagnostic purposes, but it is not
something we use to report as output. It's not something you would
typically measure in a real experiment. I'll ask Simo to comment on
whether 'INTEGRATED INTENSITY' should be used as you seem to want to
use it.

Maybe you could look at the User's Guide section called "The True Gas
Temperature...". There it discusses the simple model of a
THERMOCOUPLE. The 'INTEGRATED INTENSITY' is the U in the equation used
to determine the temperature of a small bead TC. So U/4 is something
like the average of the radiative flux over the entire sphere.

On Apr 16, 9:58 am, "clemen...@tpi.setec.fr" <clemen...@tpi.setec.fr>
wrote:

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> - Show quoted text -

[shostikk]

The main difference between these two quantities is actually mentioned
in their names:

"FLUX" refers to energy flux into certain direction. So, the
intensities are multiplied by the cos of the angle between the
directions of the intensity (or control angle in practice) and the
flux meter orientation.

"INTEGRATED INTENSITY" is just that, integral over the 4 pi solid
angle, as you mentioned above. All the directions are of same
importance.

Simo

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[clem...@tpi.setec.fr]

Simo Write :

> "FLUX" refers to energy flux into certain direction. So, the
> intensities are multiplied by the cos of the angle between the
> directions of the intensity (or control angle in practice) and the
> flux meter orientation.

> "INTEGRATED INTENSITY" is just that, integral over the 4 pi solid
> angle, as you mentioned above. All the directions are of same
> importance.

So I supposed that Radiative heat flux take in account the absorption
coefficient of the cell ?
At contrary Integrated intensity do not, Am I right ?

[dr_jfloyd]

Look at Chapter 7 in the Technical Manual. In particular equations
7.8 (defines radiant flux) and 7.9 (defines U ,the integrated
intensity).

On Apr 19, 4:52 am, "clemen...@tpi.setec.fr" <clemen...@tpi.setec.fr>
wrote: