bulk temperature about a Area
I new in OpenFoam user and I try to get the bulk temperautre about a area.
the theory: my problem
tbulk = integration(U*T*dA) / integration(U*dA)
I'm not really sure how to sovle this problem.
Postprocessing or ?
I think that you need a summation about the area,like:
sum = sum + T(n)*U(n)*dy (Fortran 2D)
How can i fixed this problem?
Have somebody a idea?
There are two issues. How to define the area and how to parallelise.
I would also advise you to use the flux rather than the velocity since it is guaranteed to be conservative.
Neglecting parallelisation issues and assuming that you want to work with patch (iP) the following will the job:
sorry for this Question. But i'm not in used to work with openFoam.
what means [ip] ? It is for direction, like [x].
I'm not sure if i get you wrong:
Your equation mean:
Is there no multiply wirh dy and dx?
thanks for your private message (in German). I hope you don't mind if I repeat what I understand is what you are trying to do.
Valentin is seeking to evaluate the local Nusselt number and needs the bulk temperature to do so. The local Nusselt number would be per wall face (additional averaging may apply) and the bulk temperature is a function of the axial position in the pipe (x-coordinate in his case).
The problem is now to evaluate the bulk temperature for a given axial position.
Is this correct?
that's right. I search for a summation (lilke (sum(sum( T.yz*U.yz*dy)dz)each Cells) about an area (yz).And every summation should go every cells in x-> direction.
Perhaps somebody has an idea.
Okay. I would try the following. Create a lookup table for T_bulk as a function of x. To do so, you need a function that maps x into an index.
This is by no means elegant, it will not parallelise easily and there are better ways of doing this. However, this will get you a long way.
thanks a lot.Have a nice evening (in German).
could you calculate bulk temperature along pipe axis ? i search for it too
bulk Temperature + cell selection
hi dear foamer
i have a pipe! its axismyetric and it is 40*160! i want to have the cells in each cross section means the cells with the same highth!
so i should have a list, this list has 160 sublist, each sublist contains the cell IDs of in each highth! so it should be 40!
i wrote above code to make a list of list!!! it compiles well but the result is some how strange and it dose not return all cell selections in each height i expected it returns 40 cells in each height but you can see the results.can anybody tell me why?
19 // it should be 40 cells!
5(84 85 87 117 119)
8(244 246 247 262 265 266 275 278)
Hi nima sam and Bruno
I need the answer to this question, my case is an axisymetric heated pipe too, I need to calculate bulk temperature at each cross section ,tbulk = integration(U*T*dA) / integration(U*dA) to compute nusselt number.additionally it is needed for fully developed condition of T at the outlet of pipe!!
any help or hint would be appreciated!
Thanks in advance
you should write some pieces of code to gather cells in each section and then return the value of them for calculation, above structure give you hints how to go forward.
Dear Nima Sam
Thanks for your reply, your code was very inspiring for me but why it didn't get anticipated 2d array?
maybe "size()" member function returns the number of neighbour cells for a cell but in this case we need to access patches which are normal to each wall patch.Is it the problem or anything else?
the above code have been written by nimasam is very good but must be corrected till it works well. for reformation, if clause must be written as following:
I am working on heat transfer analysis in rectangular duct using ANSYS-Fluent. for calculation of local nusselt number I need bulk fluid temperature. where,
Tbulk = integration(U*T*dA) / integration(U*dA)
I am able to get Tbulk. please help me to find that.
That is one of the reasons why one pays money for Fluent: you don't have to face sarcastic answers on the MessageBoard. Paid support people are polite
Thanks for your response. BUT need help to calculate integration of UTdA in Fluent. means how to calculate integral of product of more than one variable along the length.
I would like to use the code to compute my Tbulk. But It is for me not clear, how does this code compute Tbulk and Where should I write the code?
Thanks for your help :)
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