Speed up Heat Transfer
Speed up Heat Transfer
(OP)
Hi,
I have a chamber which is in Vacuum, and I have parts that I want to cool down. The problem is the vacuum! The parts are cooling very slow, due to the fact the only heat transfer is radiation. I need to speed up the cooldown? in a controlled mannor. I have to keep the parts in a vacuum until cool.
Any ideas?
I have a chamber which is in Vacuum, and I have parts that I want to cool down. The problem is the vacuum! The parts are cooling very slow, due to the fact the only heat transfer is radiation. I need to speed up the cooldown? in a controlled mannor. I have to keep the parts in a vacuum until cool.
Any ideas?





RE: Speed up Heat Transfer
Regards,
RE: Speed up Heat Transfer
The radiation between the parts and the wall is not good enough to give a quick cool down, there is a quartz heating element between the wall and parts.
Any more ideas?
Thanks
RE: Speed up Heat Transfer
Can't you use inert gas inside the chamber?
Regards,
RE: Speed up Heat Transfer
Convection tru the part to its stand might be a way, but the part is sitting on a quartz plate, so won't get much heat flow thru that?
What do you think?
RE: Speed up Heat Transfer
RE: Speed up Heat Transfer
Are thermal straps to the cooling jacket a possibility?
Might also consider using thermal straps to a TEC cold plate. You would only turn this on during cooldown to minimize issues during heat cycle. This might at least transfer the heat elsewhere.
TTFN
RE: Speed up Heat Transfer
ztdep has the concept, we do it all the time. We insert a "shroud" into the vacuum container and circulate the cooling/heating medium through it. Liquid or gasious nitrogen is used mostly. The interior facing walls are painted black (low emissivity).
I am sure you can create your own shroud using copper sheet and attaching copper tubes to the back side (annulus). You have a space simulation chamber if you can hit the -7 scale
Good Luck
pennpoint
RE: Speed up Heat Transfer
What you really want is a high emissivity wall (cold) facing the part to be cooled. This will increase the radiative transfer. If the part can be made highly emissive, even temporarily, this will also help. Any conductive cooling by cooling the supports will also help.
I can offer analysis assistance on the system if it is of interest.
Jack M. Kleinfeld, P.E. Kleinfeld Technical Services, Inc.
Infrared Thermography, Finite Element Analysis, Process Engineering
www.KleinfeldTechnical.com
RE: Speed up Heat Transfer
Sorry, You are correct. I said "low" ment to say "high" why I don't know. Again you are correct by suggesting the use of a cold plate surface to clamp the component onto. Tube circuits can be attached to the bottom side and fluid circulated through them.
Good Luck
pennpoint
RE: Speed up Heat Transfer
I know you had this problem quite some time ago, but hopefully this will help you and others in the future.
We do a lot of vacuum thermal processing for our active heat spreaders. We need to control the surface chemistry of our devices, which is why we use a vacuum.
Sometimes we need to cool down fairly rapidly, for grain size control. We are able to cool at specific rates by introducing inert gases, such as argon, at predetermined pressures.
We have achieved cool down rates that are orders of magnitude greater than radiation cooling to the water cooled chamber.
Best regards,
Daniel L. Thomas, CTO
Novel Concepts, Inc.
http://www.novelconceptsinc.com