Phase change material in oil pan - solidification

wsh · July 29, 2015, 19:36

Hello!

I am a student. I am preparing uni project with FLUENT, but I am new to CFD. The case is thin layer of PCM which surrounds oil pan. I want to observe how quick would pcm solidify, with car exposed to low temperature (simulation is based on american diesel cold-start improvment research work, UNIVERSITY
OF DAYTON, 2000, Scott D. Stouffer, Arthur B. Lewis, Thomas J. Whitney, Michael L. Drake). Model is just pcm layer. I've added 3 BC walls: oil pan part, surrending (outer) part and engine block/chassis part. Since this is just a sketch, BCs are just const temperatures. I have run steady simulation and I got my first results which are OK.

I want to perform long transient simulation (up to 10 hours) which allows me to export animation how quick etc does pcm changes. First question is: it is possible to set one of BC (part of wall in contact with oil pan - top side of pcm model) working like "temporary" temp wall? Or temp convection/heat flow? When i say temporary I think about that oil in oil pan has some (high) temperature and, after engine shutdown, starts to transfer heat to pcm (and egnine block etc, what I skip coz Im engineer). Well, it is transfering heat earlier too but i am starting simulation after engine shutdown. But oil (and oil pan itself) has thermal mass, which is "exhausted" after some time (that means oil pan and pcm have equal temp and is not longer transfer heat to one another). BC of outer wall and chassis wall I would keep as const temp to simplify computings, it would be enough to my simulation?

I was thinking about size of FE too. Since Courant number is not computable in non-flowing simulation I can only guess.

Sorry for my English, I hope anybody can help me

Have a good night

P.S. Link to case, data and mesh files:

Code:

http://speedy.sh/8V8Ss/pon.cas

Please use virus scaner, just to be sure. Fluent 16. I am using Fluent in uni lab.

wsh · August 1, 2015, 16:31

What I need is a transient boundary condition. What I have to do is just set one of mine BC (oil pan wall part) to transient BC using a standard transient profiles (help section 6.6.5). It should be pretty simple. I've wrote a formula and I'm trying to read this file to FLUENT via Profile Dialog Box but it does not respond - FLUENT reads no data.

By the way, I've tried writing a BC profile file by Profile Dialog Box. I have choose one of my BC and selected density and temperature vales. But I've noticed that in output file fluent is saving coordinates and initial values of specific mesh (nodes?) of my BC wall rather then boundary condition set via setup -> Boundary Conditions -> Edit.

My goal is to set transient thermal BC (temperature) on one of oil pan walls and I am confused.

I would be grateful for any help!

I added my BC transient profile file (which is not working).

I don't know if it's correct to double post so please merge if need.

Quote:

((miska-empbc transient 71 0
(time
0
60
120
180
240
300
360
420
480
540
600
660
720
780
840
900
960
1020
1080
1140
1200
1260
1320
1380
1440
1500
1560
1620
1680
1740
1800
1860
1920
1980
2040
2100
2160
2220
2280
2340
2460
2520
2580
2640
2700
2760
2820
2880
2940
3000
3060
3120
3180
3240
3300
3360
3420
3480
3540
3600
3660
)
(temperature
344
342,8
341,6
340,4
339,2
338
336,8
335,6
334,4
333,2
332
330,8
329,6
328,4
327,2
326
324,8
323,6
322,4
321,2
320
318,8
317,6
316,4
315,2
314
312,8
311,6
310,4
309,2
308
306,8
305,6
304,4
303,2
302
300,8
299,6
298,4
297,2
296
294,8
293,6
292,4
291,2
290
288,8
287,6
286,4
285,2
284
282,8
281,6
280,4
279,2
278
276,8
275,6
274,4
274
273
273
)
)

ghost82 · August 1, 2015, 16:51

Hi,
You must replace all commas with points.
Moreover you defined the series having 71 values but you have 61 values for time and 62 values for temperature (273 is repeated 2 times).

wsh · August 1, 2015, 18:37

Thanks Daniele,

shamefull mistake. I did change comas and series but unfortunately FLUENT is still not reading profile file

ghost82 · August 2, 2015, 09:54

Attach your new profile file and post more info about what you did and the error you received.

More info here:
http://jullio.pe.kr/fluent6.1/help/html/ug/node174.htm

wsh · August 2, 2015, 12:10

Yes I have red whole 6.6 chapter in Fluent 16 about using profiles.

Profile file:

Quote:

((miska-transbc transient 61 0
(time
0
60
120
180
240
300
360
420
480
540
600
660
720
780
840
900
960
1020
1080
1140
1200
1260
1320
1380
1440
1500
1560
1620
1680
1740
1800
1860
1920
1980
2040
2100
2160
2220
2280
2340
2460
2520
2580
2640
2700
2760
2820
2880
2940
3000
3060
3120
3180
3240
3300
3360
3420
3480
3540
3600
3660
)
(temperature
344
342.8
341.6
340.4
339.2
338
336.8
335.6
334.4
333.2
332
330.8
329.6
328.4
327.2
326
324.8
323.6
322.4
321.2
320
318.8
317.6
316.4
315.2
314
312.8
311.6
310.4
309.2
308
306.8
305.6
304.4
303.2
302
300.8
299.6
298.4
297.2
296
294.8
293.6
292.4
291.2
290
288.8
287.6
286.4
285.2
284
282.8
281.6
280.4
279.2
278
276.8
275.6
274.4
274
273
)
)

There is no error. I run Fluent, read case&data file, then read profile file (File -> Read -> Profile...), name of file is "miska-transbc.prof". I select it but Fluent says only

Quote:

Reading "E:\Takie tam\!PRACA\pUSTKA\miska-transbc.prof"...

Reading profile file...

and nothing is happening, the Profiles panel is empty too (Setup -> Boundary Condition -> Profiles...).

ghost82 · August 2, 2015, 12:44

Once you loaded the profile file, don't you have to load it in the boundary condition panel?
Read here:
https://www.sharcnet.ca/Software/Flu...ug/node304.htm

wsh · August 14, 2015, 07:50

After hours of changing profile file like a mad I have saved it as a text-only format, without formatting, via wordpad and it worked...

Thanks ghost82

July 29, 2015, 19:36	Phase change material in oil pan - solidification	#1
wsh New Member Dobromił Pszenny Join Date: Jul 2015 Posts: 20 Rep Power: 11	Hello! I am a student. I am preparing uni project with FLUENT, but I am new to CFD. The case is thin layer of PCM which surrounds oil pan. I want to observe how quick would pcm solidify, with car exposed to low temperature (simulation is based on american diesel cold-start improvment research work, UNIVERSITY OF DAYTON, 2000, Scott D. Stouffer, Arthur B. Lewis, Thomas J. Whitney, Michael L. Drake). Model is just pcm layer. I've added 3 BC walls: oil pan part, surrending (outer) part and engine block/chassis part. Since this is just a sketch, BCs are just const temperatures. I have run steady simulation and I got my first results which are OK. I want to perform long transient simulation (up to 10 hours) which allows me to export animation how quick etc does pcm changes. First question is: it is possible to set one of BC (part of wall in contact with oil pan - top side of pcm model) working like "temporary" temp wall? Or temp convection/heat flow? When i say temporary I think about that oil in oil pan has some (high) temperature and, after engine shutdown, starts to transfer heat to pcm (and egnine block etc, what I skip coz Im engineer). Well, it is transfering heat earlier too but i am starting simulation after engine shutdown. But oil (and oil pan itself) has thermal mass, which is "exhausted" after some time (that means oil pan and pcm have equal temp and is not longer transfer heat to one another). BC of outer wall and chassis wall I would keep as const temp to simplify computings, it would be enough to my simulation? I was thinking about size of FE too. Since Courant number is not computable in non-flowing simulation I can only guess. Sorry for my English, I hope anybody can help me Have a good night P.S. Link to case, data and mesh files: Code: http://speedy.sh/8V8Ss/pon.cas Please use virus scaner, just to be sure. Fluent 16. I am using Fluent in uni lab. Last edited by wsh; July 29, 2015 at 19:44. Reason: my english is bad indeed

August 1, 2015, 16:51		#3
ghost82 Senior Member Rick Join Date: Oct 2010 Posts: 1,016 Rep Power: 27	Hi, You must replace all commas with points. Moreover you defined the series having 71 values but you have 61 values for time and 62 values for temperature (273 is repeated 2 times). __________________ Google is your friend and the same for the search button!

August 2, 2015, 09:54		#5
ghost82 Senior Member Rick Join Date: Oct 2010 Posts: 1,016 Rep Power: 27	Attach your new profile file and post more info about what you did and the error you received. More info here: http://jullio.pe.kr/fluent6.1/help/html/ug/node174.htm __________________ Google is your friend and the same for the search button!

August 2, 2015, 12:44		#7
ghost82 Senior Member Rick Join Date: Oct 2010 Posts: 1,016 Rep Power: 27	Once you loaded the profile file, don't you have to load it in the boundary condition panel? Read here: https://www.sharcnet.ca/Software/Flu...ug/node304.htm __________________ Google is your friend and the same for the search button!

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August 1, 2015, 18:37		#4
wsh New Member Dobromił Pszenny Join Date: Jul 2015 Posts: 20 Rep Power: 11	Thanks Daniele, shamefull mistake. I did change comas and series but unfortunately FLUENT is still not reading profile file

August 14, 2015, 07:50		#8
wsh New Member Dobromił Pszenny Join Date: Jul 2015 Posts: 20 Rep Power: 11	After hours of changing profile file like a mad I have saved it as a text-only format, without formatting, via wordpad and it worked... Thanks ghost82