39078Re: [Distillers] Re: condensor
- Apr 5, 2007--- sn_cur <sn_cur@...> wrote:
> Not a physicist, but I am pretty sure that the optimal arrangement is aActually, no...turbulence is quite desirable. It's also a factor of flow, not
> balance between
> turbulence and laminar flow. Maximising laminar flow reduces heat exchange
> Maximising turbulence impedes coolant and/or vapour flow.
an impediment. The greater the flow, the greater the turbulence and the less
laminar flow. Turbulence is desirable because of the mixing effect in the
fluid where heat transfer is occurring.
However, in dealing with situations where a phase change occurs...vapor to
liquid in our case, we want more than just gross heat exchange. In our
coolant, pump like mad...the greater the flow, the better. There's the
turbulence in the coolant that makes it a more efficient heat transfer medium.
On the vapor side, however, if we raise the flowrate, i.e. vapor speed, too
much, then there isn't enough time spent in contact with the heat transfer
surface to affect sufficient heat transfer for condensation to occur. Overall,
there will be a greater magnitude of energy (in the form of heat) transferred
from the vapor to the liquid...that's not what we're after. We're not making
water heaters. Thus, the balance becomes one of heat input to condenser
capacity. But what we're broaching now is the geometry of the rig as a
whole...the power of the heat input, the size (i.d.) of the column, the area of
the vapor space within the condenser, the flow characteristics of the vapor
path through the condenser, the same regarding the coolant through the
condenser, the relative paths of each, the physical size, the temperature of
the coolant, the flow of the coolant...yadda, yadda, yadda.
...then combine all of this with the simple fact that we, at home, can only
construct something *so* elaborate without resorting to a full blown machine
shop (not that some of us don't fantasize :) ).
It can be enough to make one scrap it and grab a bottle of Jack from the store
to make the voices stop :)
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