It seems that if the problem I am having now is due to the friction of the coal particles, I could go with a larger pipe to significantly reduce the effects:
Notice that pipe diameter (D) has a DOUBLE effect on reducing the friction. I believe I have plenty of air for the lift and transfer, and even for the Dense to Dilute phase acceleration losses as the air expands.
I'm fairly sure it's the friction at the opening area, mostly due to the size and shape of the coal- made worse as more weight is applied to the coal, forcing it to settle void into void and resisting any efforts to reorient individual pieces (as in moving to suck into the pickup tube)
What to do?
Obviously, vibration and other mechanical agitation can help. I know from personal experience that the right amount of agitation can set things in motion
LOL.
What do you think about a larger opening of say 3" with about 8" of pipe, then reduce to 2" diameter?
The shift from Dense to Dilute phase should have enough length and space before the 2 inch section, which would then undergo its own Dense to Dilute phase transition, with the associated acceleration of the particles...which *should* spread out the coal pieces enough to accommodate the 3 in to 2 in change.
At least that's what I was thinking....Anyone try it? Results?
Dumb idea? Worst case would be a massive jam at the reducing point. But I think with the velocity and the fluid velocity over the coal to reduce the pressure, then the threshold to lift each piece might be enough delay to allow pieces to enter the stream in a "behaved" fashion?
If not, there's still a SHOVEL
Haha !
BTW, here is a good document with the remainder of the equations, for those of you smart enough to digest and explain it to us all