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Where can I find numbers for:
Heat transfer rates through copper, air, water, aluminum, silver, and other mediums?
Copper to water, Copper to air, aluminum to water, and aluminum to air would all also be nice if someone can find them but not really required. Numbers showing the rate the heat transfers internally of the medium are most important.
Project B: 1%. ;)
ooooh.. that would be interesting... no freeking clue.. lol.
silver to water and silver to air.. those would be handy ;)
would be a factor of like 2 or 3x for water over air i think. no numbers though
with the specific heat capacity of each material you can calculate it. im just not sure of the equation. I will look it up in google.. I would say i would look it up in my 200 dollar phsycis book, but it doesnt have more than 4 pages on thermodynamics.
I believe diamonds are supposed to have a ridiculous heat dissipation qualities.....so yeah when I hit the lotto I'm getting a diamon cut CPU water block :D
lol.. one problem man... there are no dimaonds that big... and the hope diamond (biggest in the world) costs serveral hundred million if i recal correctly.. so the lotto wouldnt even take care of the cost.. lol...
Could possibly fabricate great big cubic zirconia... maybe i'll look into that later lol.
actually, thats quite funny.. we have some of the indications of diamond feilds around here (shallow spots, red clay, etc) and may have possibly found one already (low grade though if it is)... :D
well there is this one lady (a chemist) who makes diamonds. she perfected a process to creat perfect flawless diamonds of various sizes.. im sure she could make one big enough for our needs. but who wants to pay like several hundred grand just for that.. lol... only thing is that all of her diamonds are colored. she does this so ppl cant sell them as the real thing, as they are entirely real in EVERY way and there is no differnce between these and the ones found in the ground.
I've some numbers after a thermodynamics class i took, i'll try to find them again and post them
edit : those are the numbers i have : it's the value of h the thermic transmission coefficient (i hope i have the right names as i don't know them in english)
Gases : natural convection : h = 5 to 30 W.m^(-2).K^(-1)
forced convection : h = 10 to 300 W.m^(-2).K^(-1)
Water : natural convection : h = 100 to 1000 W.m^(-2).K^(-1)
forced convection : h = 300 to 12000 W.m^(-2).K^(-1)
Oil : forced convection : h = 50 to 1700 W.m^(-2).K^(-1)
Liquid metal : forced convection : h = 6000 to 11000 W.m^(-2).K^(-1)
I hope those are the numbers who were looking for, forced convection are turbulent mouvement (which is why blocks have those design to make the water turbulent) and they allow better heat transfer
If you need any help with physics i can always take a look at some equation, it's been a while since i studied thermodynamics but a small freshening should do it ;)
I think they are.. larger numbers means they move energy (heat) faster right?
Say I put two 30cm x 1cm x 1cm peices of aluminum and copper side by side, if I applied 100w to one end of both which one is going to heat up the opposite end faster?
Thats what i'm looking for... copper is faster at moving energy than aluminum IIRC, but aluminum can dissipate it faster. Silver was somewhere inbetween. I need numbers on each one though, "liquid metal" (as in melted?) is pretty generic, unless maybe they meant mercury?
maxxx - got any contact info on her? Maybe i'll try getting in contact with her just for fun :D
Larger is better ;) this is in the case of convection meaning a transfer between a liquid and a solid
The dissipated power is : phi = h * (Temp of solid - Temp of liquid)
As for your question i would say the copper will heat up the Al
The heat transfer properties wont change no matter which direction you are going ie copper absorbs quicker but aluminum dissipates quicker is false. I think the reason this has come up is that in areas where cost isnt a factor but dissipating heat is you do see a fair amount of aluminum used, but it is usually used for a different reason weight.Quote:
Thats what i'm looking for... copper is faster at moving energy than aluminum IIRC, but aluminum can dissipate it faster.
For a given weight you can get better heat dissipation from aluminum than copper but with all things being equal copper will dissipate heat much quicker than aluminum.
Copper.Quote:
Originally Posted by STEvil
You're after the thermal conductivity.
Al 6063-T6 is 200W/m-K
Cu C110 is 388W/m-K
So copper has almost twice the conductivity of Al.
That in turn means it will convect heat better to water or air.
Its easy for solids. Just look up the thermal conductivity.
For liquids or liquid solid systems, you're in the wrong place. Theres no simple way to calculate all but the most trivial heat transfer problems, and people who deal with this stuff (MEs, AEs, etc) spend years learning physics and models that attempt to explain how fluids behave in contact with a metal, etc.
No thats not right at all. For a solid, all that matters is thermal conductivity, so you can figure out which will move heat faster just by looking at the conductivity. Copper is clearly better, by almost a factor of 2. But if you want to do things more complicated, like calculate temperature gradiants, its a mess of partial differential equations and everything stops making sense :(Quote:
Say I put two 30cm x 1cm x 1cm peices of aluminum and copper side by side, if I applied 100w to one end of both which one is going to heat up the opposite end faster?
Thats what i'm looking for... copper is faster at moving energy than aluminum IIRC, but aluminum can dissipate it faster. Silver was somewhere inbetween. I need numbers on each one though, "liquid metal" (as in melted?) is pretty generic, unless maybe they meant mercury?
There's a lot of equation who allow you to have an idea, of course it's very simplistic and doesn't work in most cases (turbulent fluid is very complex and can refer to the chaos theory). Linear fluid are quite esay to study. From the heat exchange point of view, i think it's easier to computeQuote:
Originally Posted by saratoga
anitpop, do you have any thermal transfer progs?? it would be cool to put one of our blocks cad files into the prog and do a simulation with the heat applied and watch the heat transfer through the water..
only problem would be the fact that the compuattion time would be in the months...
sorry Maxxxracer or should i say Royal Arse? :D I don't know how to use such a soft and i don't have one, all i've used is some thermodynamics equation on paper (triple integrals without a calculator is so much fun) maybe you could ask cathar, i'm pretty sure he has one of those soft and knows how to use them
ROFL!!! tripple intergrals without a Ti-89... ur mad man. integration by parts, partial fractions, trig subsititution (god i hate trig with a pasion), regular substitution.. oh the fun of integrals.
Yep i used to eat those and that was the easy part ;) All exams without a calculator, i still wonder why i bought the Ti-92 as i barely used it at least in math (believe doing some limited developpement by hand is really challenging)Quote:
Originally Posted by MaxxxRacer
lol.. u must be good at integrals.. im just learning all thos rules.. not very good at it yet..
me, i girp my ti-89 like i am holding my heart in my chest.
Thermal conductivity is :silver > copper > aluminum which I remember from high school as those are elements but I never reallylearned about anything with multiple elements like water for example.
I work at an aluminum casting plant and besides weight the bigger reason is cost. Aluminum is pretty cheap compared to anything else. Being lighter if two hs were the same weight the aluminum one would have a lot more surface area for better dissapation of the heat. The biggest question I would think would have to involve waters heat absorbtion. Using distilled water helps to keep it relatively uniform but...pure water doesn't even conduct electricity...its all the ions from various metals and stuff in the water that does that. Just my 2 cents on it, but some #s in black and white would be pretty coolQuote:
The heat transfer properties wont change no matter which direction you are going ie copper absorbs quicker but aluminum dissipates quicker is false. I think the reason this has come up is that in areas where cost isnt a factor but dissipating heat is you do see a fair amount of aluminum used, but it is usually used for a different reason weight.
true water by itself is not conductive, but you have to have it in a special container to keep it from ionizing.. even exposing it to air will ionize it. also having it deinoized in a watercooling loop it is more of a solvent than normal and would do funny stuff to the cooling loop. (but this is on a very small scale as there isnt much water in the loop, but if you ran a constant stream of fresh deionzized water through the system it would cause problems over time)
This is false, no matter how pure the water is, you'll still have a chemical reaction going on which H2O <=> H3O+ + OH-Quote:
Originally Posted by MaxxxRacer
The concentration of the ion is very small (10^(-14) ) but still existant
Maxxx, yeah i'm quite good at math in general and i had pretty advanced courses
hmm.. well for all intesive purposes its rather non-conductive. with that kind of concentration im sure it has some capacitance but not entirely conductive
As i said it's very small but still existant, i doubt it would do any harm