Insulation - SMath

Different approach. Trying to use FindRoot. Tank Wall Temperature Insulation(C).smz (242,77 KiB) descargado 1199 vez(es).
Right now, I have a manual override.

#7 Publicado: 21/3/2018 1:04:01

Jean Giraud

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Wrote
Different approach

Attach *.sm ... instead.

#8 Publicado: 21/3/2018 8:57:29

Ruben Sidranski

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Jean,

Wrote
Different approach. Trying to use FindRoot. Tank Wall Temperature Insulation(C).smz (242,77 KiB) descargado 1199 vez(es).
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 (200,1 KiB) descargado 1112 vez(es).

#9 Publicado: 21/3/2018 15:07:44

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 (102,45 KiB) descargado 1134 vez(es).

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

#10 Publicado: 21/3/2018 17:29:30

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 Publicado: 22/3/2018 12:40:43

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 (105,96 KiB) descargado 1144 vez(es).

#12 Publicado: 22/3/2018 13:41:14

Martin Kraska

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

Technische Mechanik mit SMath Studio: https://link.springer.com/book/10.1007/978-3-658-50592-9

#13 Publicado: 22/3/2018 13:52:44

Jean Giraud

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So I cannot plot ...

In red below WS

Tank Wall Temperature Insulation(F).smz (106,24 KiB) descargado 1141 vez(es).

#14 Publicado: 22/3/2018 14:18:55

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 Publicado: 22/3/2018 14:47:18

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 Publicado: 22/3/2018 14:51:32

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 Publicado: 22/3/2018 15:20:02

Davide Carpi

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Wrote
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 Publicado: 22/3/2018 16:28:44

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 Publicado: 22/3/2018 17:13:17

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.

Technische Mechanik mit SMath Studio: https://link.springer.com/book/10.1007/978-3-658-50592-9

A 1 usuarios les gustó este mensaje

ElSid 22/3/2018 17:37:00

#20 Publicado: 23/3/2018 12:29:48

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 (106,16 KiB) descargado 1130 vez(es).

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