5 Replies Latest reply on Jan 12, 2015 7:15 AM by Teresa Coronado

# simulating plate-fin heat exchangers

Hi everybody,

I am trying to simulate the flow trajectories inside an HVAC system, but I am not sure about how to simulate the plate-fin heat exchanger. I have the geometry but it so complex with all the fins and I was thinking to consider it as a porous medium. I have the pressure drop curve. Initially I do not need to simulate the heat exchange, just the air movement through the coil.

What do you think? Do you have any experience simulating this kind of heat exchangers?

Best regards

Teresa

• ###### Re: simulating plate-fin heat exchangers

sound good to me, that is basically what we did here: SolidWorks Quick Tip - Parametric Studies in SolidWorks Flow Simulation

i'm surprised you don't need to include the heat transfer though. don't you need that for a heat exchanger? things get messy when you want to do a thermal analysis with a porous medium

• ###### Re: simulating plate-fin heat exchangers

Hi Jared, thank you and happy New Year.

I don't need to simulate the heat exchange at first because I’m analyzing just the air movements inside the HVAC unit, and including the heat exchange would make the problem too complex. Initially I just want to study the envelope of the unit.

Do you have any idea about how to determine the porosity of a coil with fins? I need this parameter to define the porous medium.

Thank you in advanced, best regards

Teresa

• ###### Re: simulating plate-fin heat exchangers

The porosity is simply the ratio of open area vs. the overall area normal to your flow. The software uses this value to calculate fluid velocity through the medium. Since you know your geometry you should be able to calculate this.

• ###### Re: simulating plate-fin heat exchangers

The best option is to do EFD zooming for the heat exchange. Make a second configuration in which the complex geometry is replaced with a slightly larger simple box. Run with the same material and save those results. Then clone the study into the original configuration, but change the computational domain to start on one side of the box (preferably the side where air is coming in) and insert a transferred boundary condition. Then you can analyze just that part with very fine mesh and see how well it transfers heat.

It's what I call a cascade study: using the results from one study as the inputs in another.

• ###### Re: simulating plate-fin heat exchangers

Thank you all for your help,

Best regards,

Teresa