how effective is direct metal-to-metal contact for heat conduction?
how effective is direct metal-to-metal contact for heat conduction?
(OP)
I need to cool a 200 mm square aluminum plate, 10 mm thick to 25 deg C. Test duration is 24 hours. This plate is getting constant radiation heat from underneath, about 20W. What I plan to do is to fabricate a cold plate and place it on the subject plate. The cold plate will have copper tubing embedded on the surface, and water will flow through the copper. I will flip it over and place it on the subject plate. Now the subject plate will directly contact copper tubing with water flowing inside.
Is there an easy way to improve metal to metal contact?
Thanks.
Is there an easy way to improve metal to metal contact?
Thanks.





RE: how effective is direct metal-to-metal contact for heat conduction?
RE: how effective is direct metal-to-metal contact for heat conduction?
Best to you,
Goober Dave
Haven't see the forum policies? Do so now: Forum Policies
RE: how effective is direct metal-to-metal contact for heat conduction?
Put the following phrase in Google -
Thermally conductive compound
The whole first page of hits seems to be manufacturers like Dow Corning. You could find data sheets and instructions that will give you the specs and best performance.
Best to you,
Goober Dave
Haven't see the forum policies? Do so now: Forum Policies
RE: how effective is direct metal-to-metal contact for heat conduction?
And out of curiousity what is the abiant air temperature? And is the hot plate losing heat from the underside also through convestion?
RE: how effective is direct metal-to-metal contact for heat conduction?
TTFN

FAQ731-376: Eng-Tips.com Forum Policies
Need help writing a question or understanding a reply? forum1529: Translation Assistance for Engineers
RE: how effective is direct metal-to-metal contact for heat conduction?
RE: how effective is direct metal-to-metal contact for heat conduction?
TTFN

FAQ731-376: Eng-Tips.com Forum Policies
Need help writing a question or understanding a reply? forum1529: Translation Assistance for Engineers
RE: how effective is direct metal-to-metal contact for heat conduction?
I am now convinced direct metal contact is a bad idea (for heat conduction). I am not sure if I can lap 200 mm square, both plates. What about something like soldering wick between the plates? (if they make a mat out of fine metal wires)
I still have the option of thermoelectric cooling.
Thank you for your replies and my apology for not including "vacuum" in the description.
RE: how effective is direct metal-to-metal contact for heat conduction?
RE: how effective is direct metal-to-metal contact for heat conduction?
No, it's not. It's only bad if the design is bad. All that's required is a sufficiently intimate contact. 200mm^2 is less than 2" square, so how big are these tubes and what's their separation? That's what will determine the thickness require for the copper plate. If you're going to use solder wick, you might as well just go with direct contact. With a sufficiently cold coolant and sufficient flow, 20W is not that big a deal, necessarily.
TTFN

FAQ731-376: Eng-Tips.com Forum Policies
Need help writing a question or understanding a reply? forum1529: Translation Assistance for Engineers
RE: how effective is direct metal-to-metal contact for heat conduction?
The processor gets hot -- 67°C at case surface, 91°C at the internal junctions. 25°C is more of a challenge, but with only 20W I think it can be met.
If you could cast aluminum around your heat exchanger tubes (completely surrounding them) and machine the contact surface nice and flat for good contact with the plate you need to cool, you might get the efficiency you need without too much trouble or any goop at all.
Best to you,
Goober Dave
Haven't see the forum policies? Do so now: Forum Policies
RE: how effective is direct metal-to-metal contact for heat conduction?
1) as you suggested, I will make the mating surfaces as flat as practical.
2) Btw, I meant 200 mm x 200 mm, not 200 sq mm.
3) Yes, I will have a cold water bath sitting outside the vacuum chamber. It will pump cold water through the copper tubing.
4) The reason I don't want to fix copper tubes directly on the warm plate is I need to take it out of the vacuum chamber. The cold plate can be swung up slightly, just enough to make room for the warm plate.
5) My plan: 10 mm dia copper tubes, embedded 50% depth into the cold plate, 50 mm apart,
Any further comments would be appreciated. Thanks,
RE: how effective is direct metal-to-metal contact for heat conduction?
50-mm separation or pitch?
TTFN

FAQ731-376: Eng-Tips.com Forum Policies
Need help writing a question or understanding a reply? forum1529: Translation Assistance for Engineers
RE: how effective is direct metal-to-metal contact for heat conduction?
RE: how effective is direct metal-to-metal contact for heat conduction?
100W/m^2-c
If the cooling area is 200mm*200mm
then for 0 deg C water, I get
100*25*.200*.200= 100 watts of cooling
so the contact solution is plausible, even with less stringent surface finish.
RE: how effective is direct metal-to-metal contact for heat conduction?
TTFN

FAQ731-376: Eng-Tips.com Forum Policies
Need help writing a question or understanding a reply? forum1529: Translation Assistance for Engineers
RE: how effective is direct metal-to-metal contact for heat conduction?
RE: how effective is direct metal-to-metal contact for heat conduction?
RE: how effective is direct metal-to-metal contact for heat conduction?
TTFN

FAQ731-376: Eng-Tips.com Forum Policies
Need help writing a question or understanding a reply? forum1529: Translation Assistance for Engineers
RE: how effective is direct metal-to-metal contact for heat conduction?
RE: how effective is direct metal-to-metal contact for heat conduction?
RE: how effective is direct metal-to-metal contact for heat conduction?
TTFN

FAQ731-376: Eng-Tips.com Forum Policies
Need help writing a question or understanding a reply? forum1529: Translation Assistance for Engineers
RE: how effective is direct metal-to-metal contact for heat conduction?
RE: how effective is direct metal-to-metal contact for heat conduction?
http://mhtlab.uwaterloo.ca/cgi-bin/strip
TTFN

FAQ731-376: Eng-Tips.com Forum Policies
Need help writing a question or understanding a reply? forum1529: Translation Assistance for Engineers
RE: how effective is direct metal-to-metal contact for heat conduction?
RE: how effective is direct metal-to-metal contact for heat conduction?
The link I gave is not right; it should be http://www.mhtl.uwaterloo.ca/old/onlinetools/strip...
TTFN

FAQ731-376: Eng-Tips.com Forum Policies
Need help writing a question or understanding a reply? forum1529: Translation Assistance for Engineers
RE: how effective is direct metal-to-metal contact for heat conduction?
RE: how effective is direct metal-to-metal contact for heat conduction?
TTFN

FAQ731-376: Eng-Tips.com Forum Policies
Need help writing a question or understanding a reply? forum1529: Translation Assistance for Engineers
RE: how effective is direct metal-to-metal contact for heat conduction?
RE: how effective is direct metal-to-metal contact for heat conduction?
Please don't forget to let us know how it finally works out for you!
Best to you,
Goober Dave
Haven't see the forum policies? Do so now: Forum Policies
RE: how effective is direct metal-to-metal contact for heat conduction?
If he machined his tube holes "inside of" the Al plate so that there were water flow paths inside of a thick AL or Cu plate, rather than on top of the thin plate and only touching at the tangents , then wouldn't he get the best heat transfer rate.
Noe, he'd need a head at each end of the thick heat exchanger plate, and those two head - like any heat exchanger would need to be screwed onto the sides of the thick plate, so he'd have more machining and assembly cost.....
RE: how effective is direct metal-to-metal contact for heat conduction?
Thanks.
RE: how effective is direct metal-to-metal contact for heat conduction?
Not necessarily. I had assumed that the tubes were brazed to the copper plate, so there's a plausibly solid thermal path from the plate to the coolant.
TTFN

FAQ731-376: Eng-Tips.com Forum Policies
Need help writing a question or understanding a reply? forum1529: Translation Assistance for Engineers