I'd be extremely interested in locating folks in the cfd world who have done research & design work in & around 'compact microscale heat-transfer' surfaces.

I can be contacted per e-mail either here, or at:

<info@adthermtech.com>

I look forward to hearing from anyone who has adventured into this fascinating world.

mw... (www.adthermtech.com) (www.adthermtech.com/wordpress2) (www.adthermtech.com/wordpress3)

Really no takers out there?

Examples would be heat-transfer within the mlti-louver fin arrays in automotive heat-transfer devices eg. radiators, condensers, evaporators - as well as modern HVAC&R applications eg. domestic air-conditioning applications.

mw...

<www.adthermtech.com> <www.adthermtech.com/wordpress2> <www.adthermtech.com/wordpress3>

Not sure if we fall into your category, but we deal with volumetric concentrated solar receivers, where the absorber is made of an array of ceramic pins, and fluid is flowing across it. If you are interested in more details, have a look in

R. Ben-Zvi, J. Karni, Simulation of a Volumetric Solar Reformer, Journal of Solar Energy Engineering, 129(2), 197-204, 2007.

Thanks very much Rami. Would you be able to e-mail a copy of the paper to my e-mail address at:

<info@adthermtech.com>?

The world is getting smaller & smaller. We seem to be going beyond the point where physically-intrusive measuring elements can be used. We are thus becoming more & more reliant on numeric simulations to try & understand the micro-world. Here, we will have to become increasingly accurate in our cfd predictions - not a given at the moment.

Thanks so much. Your input is greatly appreciated.

mw...

<www.adthermtech.com/wordpress2>

Please find it in your mailbox.

Thanks Rami - paper received in good order.

Now, glancing quickly through the paper, I see they have dimensions of the order of tens of mm. To qualify for microscale, we'd need to technically simulate at sub 1mm scale. Have you tried scaling the concept down to say 1/100 of the current concept & running multiple units in a parallel array - for instance?

Would such a scaling - size reduction & parallelisation - result in process improvements? If so, then you could have an interesting project to experiment with. You could also experiment with different shaped fins & spacing patterns.

Thanks so much for your input. That's a nice concept.

mw...

This discussion diverts from numerical methods and CFD, so it may be of little interest to the forum. I therefore suggest to continue it on e-mail, if you wish. However, I'll comment on your last message.

A typical dimension in the system described in the aforementioned paper is the pin diameter, in the order of 3mm. Reducing it much further (e.g., 1/100 as you suggested) seems technically impractical to me for ceramic pins. However, we have developed another type of volumetric absorber, where the absorption is by small carbon particles (with average diameter of 0.3um) suspended in the fluid. This enabled heating the fluid in some cases to nearly 2100K and in other cases used for methane reforming.

Hi Rami,

Many thanks for your comments.

I think what I'm trying to move along with posts like this is to stimulate interest in using cfd tools to simulate in environments where practical physical measurements become impossible. At that point, we have to begin to develop & calibrate the cfd methodologies we use & develop some sort of understanding beyond mere 'pretty pictures'

In these microscale regions, cfd may become one of the only tools available to understand small-scale flow & heat-transfer phenomena.

mw...

<www.adthermtech.com>, <www.adthermtech.com/wordpress2>, <www.adthermtech.com/wordpress3>