jah-reddit
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Will mating aluminum to steel help with help with heat transfer through the steel?

Postby jah-reddit » Wed Aug 12, 2020 3:53 pm

Say I have a gallon of hot fluid (motor oil) at 250F, and ambient air temp of 80F. The oil is in a steel container that I can not modify (car oil pan). The oil currently cools down very slowly via thermal conduction through the steel oil pan transferring heat to the ambient air. Higher the ambient temp, slower the heat dissipation.

My question is, if I use thermal glue to glue an aluminum radiator to the steel pan, then run fluid through the glued radiator that is cooled from another radiator with more surface area and better airflow, is there any advantage?

Meaning, will the aluminum radiator "suck" heat faster out of the oil (through the steel pan) faster than just the conduction from the steel pan to the ambient air? Or will the heat transfer rate stay relatively the same since the steel pan is still the choke point?

rmarz
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Re: Will mating aluminum to steel help with help with heat transfer through the steel?

Postby rmarz » Fri Aug 14, 2020 11:23 pm

jah-reddit - You proposed a theoretical question, so I'll respond with a theoretical answer. I believe you can obtain improved temperature dissipation with an attached aluminum radiator. Here are my thoughts.

1) Even though the heat flow through the steel does not change, the addition of an aluminum 'heat sink' may substantially provide much greater surface area that is exposed to the ambient air to assist cooling.

2) The addition of an efficient thermal conductive adhesive to attach the aluminum 'radiator' will add some additional 'thermal resistance' to the process, but the design of the 'radiator' most likely could greatly increase the radiating area of the oil pan heat source.

Those are my thoughts, but I think it is very defensible.

Rick Marz

jah-reddit
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Re: Will mating aluminum to steel help with help with heat transfer through the steel?

Postby jah-reddit » Sun Aug 16, 2020 10:15 am

Thanks Rick! I've been mulling this experiment over for a while, and I posted the same question to a few other science/physics sites as well. Sounds like the consensus is similar: unmodified, dissipation is limited to the square inches of steel exposed to the air on the steel pan. By design, the radiator is attempting to maximize the surface area exposed to the air, thus should lower the temp of the steel faster, thereby lowering the temp of the oil.


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