Limited cooling space

[Greg Hermann]

>Frederic Breitwieser wrote:
>>
>> > The way I see it, the coolant now "sees" a radiator that is 1/3 as high and
>> > 3 times longer.  Why does this cool better than normal.  The log delta T is
>> > the same, no?  Is it a flow turbulence thing?  That is the only change I
>> > see.
>>
>> Here would be my <cough> guess...
>>
>> If you increase the width of the radiator, the coolant has to move
>> further to reach the other side and be sucked back into the system,
>> therefore its exposed to the ambient (and hopefully cooler) air
>> temperature, which reduces the temperature of the coolant going back
>> in.
>
>But, heat lost is proportional to the temperature delta.  As the water
>passes through this longer radiator you dump less and less heat because
>the temp delta is getting closer to zero.  Maybe Gary can weigh in here
>but I think you want the radiator at the highest possible average
>temperature to maximize heat transfer.  That situation is achieved by
>the "parallel" radiator, not the serial radiator.

Only thing you are doing besides increasing the pressure drop across the
radiator is increasing the turbulence in the tubes--which can increase the
heat transfer coefficient from the fluid to the tubes from a little to a
lot, depending on whether the radiator was a good or bad design in the
first place.

Regards, Greg
>
>
>--steve
>
>--
>Steve Ravet
>steve.ravet at arm.com
>Advanced Risc Machines, Inc.
>www.arm.com