Why is it called pressure drop when the plenum pressure is increasing ? The pressure drop occurs at the peak when the particles lift of creating higher voidage for flow . Could it be perceived as pressure change instead of pressure drop ? Giving it a negative value is making it hard for me to bring it home . Its a conflict
Assuming that all your particles have the same diameter. How do you calculate the velocity at which all the particles will be carried away by the gas and eventually leave the column?
The simple assumption would be that particles entrained in the gas will move at the same velocity of the gas. In reality, gravity is still acting on them so they would be moving a little slower than the gas itself. For dilute particles that you can treat as individuals, you can calculate the terminal settling velocity and subtract that from the overall gas velocity (but it will be in turbulent flow so it's not possible to be too precise).
