Hi Chris,
maybe you realise that I am trying to get a bit deeper into the code. And for the drag law I have some questions:
1) For the calculation of beta (I think it is mostly called this way) you used the term alpha^(1-xi). In different publications I found three different exponents: -xi, 1 - xi and 2 - xi
I haven't received the original paper, yet, so I don't know which is the correct one.
2) In the code you are using the voidfraction to calculate the Reynolds number. This Reynolds number is than used for the calculation of the drag coefficient (line 117, beginning with Cd = ...). Is it the correct way?
3) Am I right that the calculation of the drag coefficient is based on drag laws for single spherical particles? As I think the used drag law is very old (Dalla Valle, 1948) and only valid below Re < 20000 don't you think it is worth using a newer, maybe more complex one?
Kind regards,
Stefan
cgoniva | Thu, 07/07/2011 - 17:40
Hello Stefan, digging through
Hello Stefan,
digging through the code and questioning the equations is part of open source and highly appreciated :-)
ad 1 and 2)
we also found different correlations (versions) in different papers. We chose that one as it fits best with other correlations from literature (e.g. Koch & Hill).
I'll have a look if I can give you the citation of the drag correlation (Di Felice) we implemented.
ad 3) Di Felice Drag might be not the latest but widely used. Consider it as a good guess and strating point. And yes it is based on a drag law for spherical particles corrected by influence of other particles (voidfraction).
Cheers,
Chris