Increasing venturi diameter in solids conveying eductor 1

[MarkkraM]

We've been getting frequent blockages in our solids conveying eductor. It seems like the odd large particle is getting stuck in the venturi throat. What would the effect of increasing the venturi throat diameter (by about 20%) given the same motive gas nozzle size and pressure, and suction gas pressure.

I think I've seen design curves before for the optimum ratio for the ratio of the area of the motive gas nozzle and the venturi throat? I'm guessing the optimum is wrt pressure recovery?

 

[m777182]

By increasing the dia of the Venturi throat you will decrease the effective jet velocity.The specific ratio length of mixing/diameter of mixing, Re number and deltaP will be different so you will move from the (probably near optimum) operating point of your device.Your transport capacity should decrease and the mass flow will be likely less stable- you ejector will "spit".Try to solve problems at the ejector intake side: insert a sieve or a small crusher and make your material free flowing. There is a nice report about eductors (in German language)by H.P.Schlag, The VDI Berichte Nr 313/3 about experimental and theoretical basis for calculating design curves for gas driven single phase injectors.
M777182