# Contact Cooling

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1. Apr 12, 2017

### Lewisjamesfc

Hi,

I am designing a system to cool aluminium through contact cooling. I have a steel die with
9x 20mm diameter cooling chambers. Water is pumped through the chambers which cools the steel die and hopefully the aluminium sitting on top of it.

I am looking to find the temperature of the water needed to cool the steel at a rate of 100C / s. Obviously this is much more complicated than a standard convection and conduction equations. I was just looking for some advice on where to start.

Thanks,
Lewis ( A stressed student )

2. Apr 12, 2017

### Nidum

Please tell us some more about this problem .

A sketch of the aluminium component and the die would be helpful .

3. Apr 12, 2017

### Lewisjamesfc

Yeah sorry, I have attached a diagram of the system and drawn the aluminium part to the side but it would normally sit on top of the shaded tool steel die inside the base that has the chambers.

Basically the aluminium is placed in the die at 550 degrees c which should then be cooled by transferring the heat to the water traveling through the base (in Theory) by 100C per second.

BASE:
L=340mm
H=100mm
W= 500mm

DIE:
L=340mm
H=50mm
W=410mm

COOLING CHAMBERS:
L=340mm
D=25mm

ALUMINIUM
L=340mm
W=410mm
H=5mm

Any help would be greatly appreciated,
Thanks,
Lewis

#### Attached Files:

• ###### Heat transfer diagram.pdf
File size:
408 KB
Views:
57
4. Apr 14, 2017

### Baluncore

You specify an initial maximum rate of cooling as 100°C/sec, but not what temperature it must fall to before the Al is removed from contact with the die. That will decide the contact time with the die and therefore the heat that must be removed from the die by the water.

The best heat transfer would be when the Al was clamped between two such cold steel dies. The moment clamping pressure is removed the rate of heat loss will be reduced by the air gap that will form as the Al changes radius by differential cooling.

Flow of heat from the Al to the water through the tool and cast steel will be slow compared with the rate of Al cooling, so it will be the mass of the cold tool steel in the die that cools the Al. For that reason the die will probably need to be cooled continuously. You will be limited to a cycle time by the heat content of the Al and the rate of heat removal in the water. If the process cycle repeats then the internal temperature of the die should be monitored so as to prevent over heating of the die. A hotter die will not rapidly cool the Al.

1. At what temperature can the Al be removed from the die?
2. How much thermal energy must be removed from the Al to drop the Al temperature from 550°C to the removal temperature?

5. Apr 17, 2017

### rbelli1

What is the goal of this apparatus? What is causing the aluminum to become hot and why?

Why was steel chosen? Can you use another material for the cooling block?

BoB

6. Apr 17, 2017

### Lewisjamesfc

Hi, thanks for replying.

A furnace, to change the micro structure.

I have simplified it, into steps and hopefully you might be able to help

Consider two pieces of metal, one at 550C and one at 25C. When they come into contact how would I calculate the temperature of the cold body after 2 seconds?

Any help would be greatly appreciated,
Thanks, Lewis

7. Apr 17, 2017

### rbelli1

If the shape of the die is not imparting any physical change to the aluminum I would suggest using an oil or water bath to alter the temperature.

BoB

8. Apr 17, 2017

### Lewisjamesfc

Ah okay thank you for your help!

9. Apr 18, 2017

### Nidum

How a particular plate cools and how heat is transferred to the die will be determined by several different factors including some completely random ones .

The reality is that every time you cool a plate by this method the results will be different .

Please tell us more about what you actually want to achieve in this part of your work .

Last edited: Apr 18, 2017
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