How is the radiator different from the tube? Heat transfer is about
temperature difference, flow rate and turbulent flow. The greater
temperature difference the faster the heat transfer.
If you slow down the flow thru the radiator you at the same time slow it
down at the tube.
Faster flow increases turbulence and decreases heat layering giving better
contact to the oil/metal surface. Slow flow allows layering of the heat in
the oil which acts like an insulator as it flows slower near the metal
surface. Faster flow causes more turbulence which breaks up the layering
reducing the insulating action. Better heat transfer.
See:Laminar flow.
73
Gary K4FMX
> -----Original Message-----
> From: Amps [mailto:amps-bounces@contesting.com] On Behalf Of Steve
> Wright
> Sent: Sunday, March 29, 2015 11:21 PM
> To: amps@contesting.com
> Subject: Re: [Amps] more - oil bath GS-35b
>
>
>
> On 30/03/15 17:01, Gary Schafer wrote:
> > You do not need to slow the flow down in order to pick up heat. The
> faster
> > the flow the more heat will be transferred.
>
> Correct! The faster the oil flow in the tube cooler, the better the
> cooling.
>
> But not so for the radiator. The oil must slow down and be in the
> radiator for a finite time for the heat to be transferred from the oil
> to the air.
>
>
>
> > On another note, you will need as much air movement to cool the
> radiator as
> > you would need to cool the tube directly. With oil cooling you are
> only
> > moving the heat from the tube to the radiator. You still have the same
> > amount of heat to transfer to the air.
>
> Sure.
>
>
> > Although with the radiator the surface area to cool will be much
> larger than
> > it is with air cooling the tube so the air velocity can be lower.
> >
>
> Exactly! Very much lower, and very very much quieter. I want to sit
> next to my quiet amp - not my vacuum cleaner.
>
>
> Steve
>
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