Hello,
I would like to calculate Fluidization minimum speed velocity (Umf) and Archimede Number for a continous air bed.
I know
- volumic masses of gaz (=1,14 kg/M^3) and particule (=500kg/M3),
- viscosity of gaz (= 1.8**-5 Pa.s)
- diameter of particules (0,000484 m)
I can't know the porosity.
Also, I've determine experimentaly the Umf (0,4 m/s) . Now I would like to calculate it in order to extrapolate it with other particules types.
Does anyone knows what kind of formula I should use, or maybe an modelisation could be efficiant ?
many thanks in advance,
Regards.
Juliette Parrott, There are many textbooks on chemical engineering and chemical reactor engineering which present many appropriate criteria equations, e.g. Romankov equation. Many different factors are important here, e.g. not only the size of the particle, but its shape. Correct some terms: like "speed velocity" (gas velocity), "volumic masses ....." (better density of gas and particles) and "air bed" (fluidized bed).
Mirosław Grzesik , thanks a lot for your reply and for correcting my terms !
I have looked at Romankov equation but I do not have the sphericity of my particule. I've based my maths on the Botteril and Teaoman equation , that does not requiere sphericity but Umf is always under-estimated.
Juliette Parrott, Romankov equation, given as an example, does not take into account the shape of the particle. There are others that include not only the particle shape. Using e.g. Leva equation for pressure drop, one can obtain the critical velocity (umf) equation taking into account the shape factor. Obviously, the problem is the porosity of the bed corresponding to critical velocity. It should also be remembered that the error of the values calculated with the criteria equations can be as much as 30%.