and p.s. regarding your 'hat in hand' feeling:
"nothing about any of this is easy, and it never will be"
~me~ just now
Quoting [email protected]:
Ralphy,
I made a spreadsheet a while back to work the Darcy-Weisbach
friction loss formula 'by hand'. The kinematic viscosity is a
required input, and is the absolute viscosity divided by the
density. I wanted to be able to vary the temperature too, and since
density is a function of temperature, I put some
formulas together to calc the absolute viscosity based on temp and
density. In doing this I discovered why I think these look-up tables
have a wider range of data for temp and density than for viscosity--
imagine parallel steel plates 1 foot apart (top and bottom), with a
fluid in-between-- if the top plate is 1 square foot, the viscosity
of the fluid would be a measure of the force required to slide the
top plate with a velocity of 1 foot per second. This force should
actually be measured for the particular fluids at the particular
temps and that is why I think the tables only go so far. The
formulas I put
together based on heat loss theory (friction) might become
increasingly inaccurate the further they get from actual measured
conditions, for any liquid fluids other than pure water.
The way I try to deal with the percent by weight vs volume is with
Specific Volume-- the inverse of density,i.e., if the weight density
of water at 40F is 62.4 lbs/ft3, the specific volume is .016 ft3/lb.
If the weight density of propylene glycol at 40F is 9 lbs/gal and we
figure 7.48 gal/ft3, the weight
density would be 67.3 lbs/ft3, and the specific volume would be
.0149 ft3/lb. (then I have to scratch my head til i find what i'm
looking for).
brad
Quoting "å... ...." <[email protected]>:
Ralphy appears to be more in need of datapoints, than data conversions.
0 C = 32 F
-18 C = 0 F
-40 C = -40 F
Back in the day, Prausnitz and Reid had the best estimation techniques for
gases and liquids.
Today, Prausnitz is in fifth edition of this book, with Poling as chief
author, 91 usd on
Kindle<http://www.amazon.com/Properties-Gases-Liquids-Bruce-Poling/dp/0070116822>.
But with all the glycerine production these days, I am sure some libraries
have this data, if not your local biodiesel facility.
Scot Deal
Excelsior Fire/Risk Engineering
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