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I agree, Charlie, curve did not "look" like exponential
curve. But, I think that may be dependent on the dimensions selected to
plot. For instance, here are two graphs with a 10" duct length,
24 sq inch duct inlet and 100 sq inch core - about what the GM core size is with
my inlet size.
A graph of the wall coordinates of the speakers would
probably look like a trumpet horn (as best I recall), in this case it is the
plot of the cross sectional area that is exponential.
The cross sectional area curve looks more like an
exponential curve than does the plot of distance from centerline to duct
wall.
If you plot a straight wall duct's area your will find it
generates a parabolic curve. If you plot the area of a streamline duct you
will find it plots out to a linear curve. The wall coordinates for the two
are draw just the opposite function than does the area.
I used the exponential curve fitter of excell and it drew
an exponential curve line right through all the points, so like I said - I think
it depends on the scale and data points you want the equation to match the curve
to.
In any case, I have not found any data on its
effectiveness - so could be good or not so good.
Ed
----- Original Message -----
Sent: Thursday, March 16, 2006 10:39 PM
Subject: [FlyRotary] Re: finding a radiator
> the mallorys
wrote:
>
>> Ed,
>>
>> I did some plotting, and
here is what I came up with:
>> The red line is a straight sided square
duct,
>> Light blue is the exponential Horn duct square,
>>
Brown is the streamline duct square.
>>
>> I don't know if the
exponential horn differs enough from a straight
>> line to make a
difference.
>>
>> Chris
>
>
> In a former
life, I built exponential horn loudspeakers for concert
> sound systems.
The rate of expansion was much greater than what's shown
> on the graph.
Perhaps the loading of the heat exchanger alters the
> formula, but at
first glance, something doesn't look right.
>
> Charlie
>
>
> --
> Homepage: http://www.flyrotary.com/
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