3 replies to this topic

[bobbobs]

Hi,

In a pipe that is flowing vapor in one direction and liquid in the other, is anyone familiar with methods to make sure that reverse flow of the liquid does not occur? One method that I have come across is to calculate the Froude number and make sure that it is equal to or less than unity. Any insight would be greatly appreciated. Thanks!

[daryon]

Hi,

In a pipe that is flowing vapor in one direction and liquid in the other, is anyone familiar with methods to make sure that reverse flow of the liquid does not occur? One method that I have come across is to calculate the Froude number and make sure that it is equal to or less than unity. Any insight would be greatly appreciated. Thanks!

The only scenario I can think of which sees vapor flowing in one direction and liquid in the other within a pipe is self venting gravity flow. Is this what you're asking about? If so you won't get reverse flow of liquid, but you may entrain gas in the liquid and restrict flow, this is where the froude number comes into play. You must keep the liquid velocity low enough to allow the vapor to flow counter-currently to the liquid.

For self venting flow in vertical pipes it's a good idea to limit the Froude No. to 0.5. A very good soruce of information on self venting gravity flow is an article by Hills called 'Designing piping for gravity flow'.

Hope this helps.
Sorry if it's not what your asking about, but please do let me know how else you flow vapor and liquid counter-currently within a pipe??

[Qalander (Chem)]

Hi,

In a pipe that is flowing vapor in one direction and liquid in the other, is anyone familiar with methods to make sure that reverse flow of the liquid does not occur? One method that I have come across is to calculate the Froude number and make sure that it is equal to or less than unity. Any insight would be greatly appreciated. Thanks!

Dear Good Evening

Only in a vertical pipe of large diameter having two phases(vapor& liquid )flowing under gravity this can be envisaged; even there may be counter current carrying gas stream taking vapours up and liquid coming downward.

[Zauberberg]

Bobbobs, read the attached article from A.Sloley:

Attached Files

•  A. Sloley - Gravity Flow.pdf   80.92KB   58 downloads