Insulation - SMath

Different approach. Trying to use FindRoot. Tank Wall Temperature Insulation(C).smz (242 KiB) downloaded 65 time(s).
Right now, I have a manual override.

#7 Posted: 3/21/2018 1:04:01 AM

Jean Giraud

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Different approach

Attach *.sm ... instead.

#8 Posted: 3/21/2018 8:57:29 AM

Ruben Sidranski

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Jean,

Wrote
Different approach. Trying to use FindRoot. Tank Wall Temperature Insulation(C).smz (242 KiB) downloaded 65 time(s).
Right now, I have a manual override.

This is Rev "C" so it's a NEW file

With that said, I am attaching Rev "D". I cannot figure out the error. Value is now coming in correctly. Attached is a screen shot of a "scratch" file I created with just the variables Tank Wall Temperature Insulation(D).sm (200 KiB) downloaded 52 time(s).

#9 Posted: 3/21/2018 3:07:44 PM

Ruben Sidranski

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Not sure what I did, but FindRoot seems to have worked ...
Sanity check Rev E? Tank Wall Temperature Insulation(E).smz (102 KiB) downloaded 52 time(s).

Next is to add a plot --> Ins. thickness vs. T1

#10 Posted: 3/21/2018 5:29:30 PM

Jean Giraud

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Not sure what I did,

There is a closely related example in Mathcad, just a bit [a big bit] more involved.
My expertise on that is about a thermostated tank, once insulated from some of the
reference you mentioned, and local standards vary.
*.smz = 103 kB ... *.sm = 102 kB

#11 Posted: 3/22/2018 12:40:43 PM

Ruben Sidranski

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Graphing problem with units not cancelling out. Go to bottom of page. Essentially, all values are calculated with Kelvin. I change the units in the array to F and we are OK.
I then try and divide by F, and I get K over F. So I cannot plot ...

Also, my program updated this morning to 0.99.6654
File version F Tank Wall Temperature Insulation(F).smz (105 KiB) downloaded 59 time(s).

#12 Posted: 3/22/2018 1:41:14 PM

Martin Kraska

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2018-03-22 17_40_02-SMath Studio - [Tank%20Wall%20Temperature%20Insulation(F).smz_].png

Martin Kraska Pre-configured portable distribution of SMath Studio: https://en.smath.info/wiki/SMath%20with%20Plugins.ashx

#13 Posted: 3/22/2018 1:52:44 PM

Jean Giraud

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So I cannot plot ...

In red below WS

Tank Wall Temperature Insulation(F).smz (106 KiB) downloaded 54 time(s).

#14 Posted: 3/22/2018 2:18:55 PM

Ruben Sidranski

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Jean,
I need the Y axis in degree F. This plots to Kelvin.
Also, why did you define "isolate"? I should be able to use augment straight up ... shouldn't I?
Also, how did you scale the graph?

#15 Posted: 3/22/2018 2:47:18 PM

Jean Giraud

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Jean,
I need the Y axis in degree F.This plots to Kelvin.
Also, why did you define "isolate"?I should be able to use augment straight up ... shouldn't I?
Also, how did you scale the graph?

I'm reworking a bit the project, pretty messy.
Hope it's correct from your reference(sss)
Bloody Imperial system !
Instead of scaling the graph, use X_Y Maxima.
Isolate to get rid of Units for plotting.
Maybe multiply by the conversion K => F

Jean

#16 Posted: 3/22/2018 2:51:32 PM

Ruben Sidranski

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Thank you Jean. The units should be adjustable per https://en.smath.info/forum/yaf_postst4793_Ploting-equation-with-units-does-not-work.aspx. I was trying to use the built in units to convert, but had the same issues going to degrees C.

#17 Posted: 3/22/2018 3:20:02 PM

Davide Carpi

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I was trying to use the built in units to convert, but had the same issues going to degrees C.

Nice worksheet.

Have you tried with the solution porposed by martin? (°F instead of °C of course)

Wrote

2018-03-22 19_16_47-SMath Studio - [Tank%20Wall%20Temperature%20Insulation(F).smz_].png

2018-03-22 19_23_29-SMath Studio - [Tank%20Wall%20Temperature%20Insulation(F).sm_].png

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#18 Posted: 3/22/2018 4:28:44 PM

Ruben Sidranski

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Martin,
I totally spaced your graphic. Can you explain the -0 degree C or F concept as this was not intuitive? I understand the delta T since we are subtracting temperatures ... Maybe this is just the work around and I answered myself

Now the better part ... a loop. As the surface temperature is allowed to remain warmer, the thickness will increase. This should be similar to the Colebrook loop. I need to find my notes on that sheet.

#19 Posted: 3/22/2018 5:13:17 PM

Martin Kraska

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Temperature gauges/units are special in that they may differ by a factor and an offset from a reference gauge. When using gauges without offset, just like K or °Rankine you can obtain the unitless numeric value by dividing the quantity by the unit. When you have an offset, you have to remove this first, hence the -0°F term. Then you divide by the relative unit matching your gauge.

Martin Kraska Pre-configured portable distribution of SMath Studio: https://en.smath.info/wiki/SMath%20with%20Plugins.ashx

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ElSid 3/22/2018 5:37:00 PM

#20 Posted: 3/23/2018 12:29:48 PM

Ruben Sidranski

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OK, going back to sanity check some values. I'll work on the look after I get the units right.
Martin,
I thought I canceled out units per your comment above in the new FindRoot equation
Version G Tank Wall Temperature Insulation(G).smz (106 KiB) downloaded 52 time(s).

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