# Viscous fluid flow in a manufacturing process

• czechman45
Increasing the diameter will not work as the bridge will form at the same diameter regardless of size. Reducing the viscosity will work, but will cause the fluid to heat up and potentially cause other problems.

#### czechman45

In work that I've been doing, we've come across an interesting problem. In a manufacturing process, a highly viscous, non-Newtonian fluid goes down a vertical chute and then gets pushed horizontally out the bottom by some rotating screws. Sometimes, the fluid gets pushed out the bottom, but the fluid in the chute doesn't continue to come down. The company that has this problem calls it 'bridging' where you essentially get a little cave at the bottom, the 'bridge' forming the roof and preventing the fluid from continuing to come down. I would like to know more about this. Does anyone know what this type of phenomena is called and where I might look to learn more about it?

Thank you!

czechman45 said:
In work that I've been doing, we've come across an interesting problem. In a manufacturing process, a highly viscous, non-Newtonian fluid goes down a vertical chute and then gets pushed horizontally out the bottom by some rotating screws. Sometimes, the fluid gets pushed out the bottom, but the fluid in the chute doesn't continue to come down. The company that has this problem calls it 'bridging' where you essentially get a little cave at the bottom, the 'bridge' forming the roof and preventing the fluid from continuing to come down. I would like to know more about this. Does anyone know what this type of phenomena is called and where I might look to learn more about it?

Thank you!
I never heard of bridging happening with a viscous fluid, but is a common phenomenon in hopper feed with granular solids and powders. Look up bridging of granular material in hoppers.

Thinking about this I suspect the bridge formation is a function of viscosity and diameter. If you can influence either you can influence the probability that the bridge will form.

Can you increase the diameter or reduce the viscosity (maybe with heating)?