AnsweredAssumed Answered

how to "pump" closed waterloop inside internal flow analysis with airflow?

Question asked by Evox Padubal on Mar 2, 2016
Latest reply on Mar 26, 2016 by Evox Padubal

Hello fellow simulators,

at the moment i'm trying to do some flow analysis with airflow and a closed waterloop inside an internal analysis.
It's basically a cube with fans inside which generate an airflow loop.

This selaed box is connected to a outside by a "wall of constant temperature" BC.

Inside this cube is some other hardware whch generates heat and of those parts is equipped with a closed water loop (necessary for scientific reasons, not cooling).
You can see a pretty easy principle sketch in the attachments.


I made some first runs without the waterloop. Everything is working fine so far.

Now the next step is to implement the water loop. I did this as as fluid subdomain but the problem is the piping of the water.

I often read about "use a fan as pump", so did i. I placed a "internal fan" inside the pipe defined with a specific volume flow rate.

Now i have two issues:

1. i get the error "mass flow out of fan curve's range"
maybe this is a problem caused by the different densities of air and water and the "internal fan" is programmed to work only with air?...idk

Btw. the fan curve reaches from 0 to 3.5 bar with specific volume flow rates, the pressure inside the water loop should not exceed that range...


2. the estimated sim time rises from previous, fine 7h to massive 60h (~500k cells)

(i know, that there's still the option to replace the heat exchanger (low performance fin cooler -> thick and few fins) with a porous media, but i gues this won't serve a big advantage this time.)


The aim is to see the temperature distribution of the inner cube and how fast it's getting homogeneous, so i think i can't get rid of simulationg that water loop...


Hopefully there's someone out there who has a good idea...
Thanks in advance, guys!