[TRNSYS-users] Hconv and convective heat transfer coefficient

Wirich FREPPEL freppelw at noirot.fr
Wed Feb 28 06:21:44 PST 2018


Hi everyone,

I ran 3 different simulations with TRNSYS, in which the only parameter I 
changed was the convective heat transfer coefficient CHTC (as seen in 
picture 1). It seems that nothing really differ from a simulation to 
another, though I tried with h=1, then h=100 (see picture 6 which shows 
the airnode temperature). Then, in order to identify the problem, I set 
as output the HCONV (type 108) and the resistance between the surface 
and the starnode Req (type 86).

Two observations :

1) HCONV does not correspond to the CHTC I set in TRNBUILD (even by 
dividing it by the surface area)

2) Req is very close to 0. I guess that's why I observe no real 
difference between each simulation.

So I've got a few questions:

1) What am I actually observing with HCONV?

2) Why is Req close to 0 ?  And what does it mean? (I assume that when 
Req=0, there is no heat transfer by convection between the surface and 
the airnode)

Thanks in advance for the clarification

-- 
Wirich FREPPEL
Ingenieur Doctorant en Recherche & Developpement
Centre R&D de Noirot - Groupe Muller
8 rue Louis Ampere, 02030 Laon
+33 (0)3 23 27 31 99

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