Hi everyone,
In the WUFI help file on "Moisture storage function", it is stated that the temperature dependence of the moisture storage function is marginal and therefore ignored.
However, we have experimental results that invalidate this statement for our materials.
In addition, we are working on materials with properties such that the characteristic time scales for heat and moisture transfer are similar.
So I have two questions:
- do you have any workaround to suggest with the current version of WUFI?
- is there any plan to introduce 2D maps of moisture storage function, W(RH, T), in future release of WUFI2D?
Thanks a lot for your help and suggestions,
Bruno
Temperature dependence of moisture storage function
-
Huet Bruno
- WUFI User
- Posts: 4
- Joined: Tue Oct 09, 2012 9:16 pm -1100
-
Manfred Kehrer
- WUFI International Support Team
- Posts: 351
- Joined: Thu Mar 10, 2005 2:17 am -1100
- Location: Northbrook, IL; USA
- Contact:
Hello Bruno,
of course temperature dependency is seen in most materials. On the other hand according to my experiences it has not that impact on most of the results compared to many other (uncertain) phenomena (e.g. huge variety in materials at all, ...)
I would suggest to carry out calculation with both of your Moisture Storage Functions and look whether it has really an impact to your final results.
In my knowledge there are no plans to implement the temperature
dependency of the moisture storage function.
of course temperature dependency is seen in most materials. On the other hand according to my experiences it has not that impact on most of the results compared to many other (uncertain) phenomena (e.g. huge variety in materials at all, ...)
I would suggest to carry out calculation with both of your Moisture Storage Functions and look whether it has really an impact to your final results.
In my knowledge there are no plans to implement the temperature
dependency of the moisture storage function.
Manfred
Wiss, Janney, Elstner Associates, Inc.
Official WUFI® Collaboration Partner for USA/Canada
Enjoy WUFI®
.... It is easy and complex.
Wiss, Janney, Elstner Associates, Inc.
Official WUFI® Collaboration Partner for USA/Canada
Enjoy WUFI®
.... It is easy and complex.-
Huet Bruno
- WUFI User
- Posts: 4
- Joined: Tue Oct 09, 2012 9:16 pm -1100
Thanks for your quick answer !
The water content at constant RH (70%) changes by a ratio of up to 1 to 10 when the temperature varies in the range [20-70] C.
I have run some drying examples as you suggested, assuming constant temperature (no coupling) but using the isotherm obtained at various temperature.
The resulting evolution of water content profile is then quite different and can change from an usual diffusion like profile (erf) to a front like profile (S shape).
Also the averaged mass loss dynamic or time to reach steady state are significantly different.
Maybe I could send you my WUFI project?
Can users submit suggestions for new developments?
Thanks again,
[/list]
The water content at constant RH (70%) changes by a ratio of up to 1 to 10 when the temperature varies in the range [20-70] C.
I have run some drying examples as you suggested, assuming constant temperature (no coupling) but using the isotherm obtained at various temperature.
The resulting evolution of water content profile is then quite different and can change from an usual diffusion like profile (erf) to a front like profile (S shape).
Also the averaged mass loss dynamic or time to reach steady state are significantly different.
Maybe I could send you my WUFI project?
Can users submit suggestions for new developments?
Thanks again,
[/list]
-
Christian Bludau
- WUFI SupportTeam IBP
- Posts: 1186
- Joined: Tue Jul 04, 2006 10:08 pm -1100
- Location: IBP Holzkirchen, the home of WUFI
- Contact:
Hello Bruno,
we discussed already to add the probability of adding also a temperature depending moisture storage function, but we skipped that at moment because the measurements would need many time and we have nearly any data for that at the moment. But maybe we will implement that in future, if there is demand on the market.
If you like to submit some suggestions to the software, you are welcome to do that. Please send a mail to support@wufi.com.
We will talk about that and see if its possible to convert the idea.
Best regards,
Christian
we discussed already to add the probability of adding also a temperature depending moisture storage function, but we skipped that at moment because the measurements would need many time and we have nearly any data for that at the moment. But maybe we will implement that in future, if there is demand on the market.
If you like to submit some suggestions to the software, you are welcome to do that. Please send a mail to support@wufi.com.
We will talk about that and see if its possible to convert the idea.
Best regards,
Christian