Why Does Air-Lock Reduce Fluid Flow in Tubes?

[sarmin]

Hi,

I have come across "air-lock," as a concept to explain decreased flow of fluid in a tube as a result of air bubbles introduced into the system. I'd really appreciate an explanation for why this happnes? is it because air is compressible? is there a text that would recommend as a reference? Thank you.

 

[abercrombiems02]

Yes, you are correct about air being compressible. Imagine a tube with a constant cross sectional area. If an air bubble is introduced into a system that previously had steady flow, then what happens is the pressure in the bubble and the water need to balance. In order to achieve this some of the kinetic energy in the stream is used to compress the air bubble. The fluid does work on the bubble by changing its volume so that the pressures are equal. (Remember E = P*V). So some of the kinetic energy in the stream is lost as result of doing work on the bubble. This increases the entropy of the system. Same result of the prescence of friction. So we can think of the bubble as being a source of friction in the flow. As for the text's I really don't know of one that addresses this problem specifically, but I do recommend "Fundamentals Of Aerodynamics" By John D. Anderson. After talking about some aspects of compressible flow there is a section on Poiselle (spelling) Flow, which is the case of viscous flow in a pipe

 

[GSXR750]

Hi there,

The air-lock concept is often used in fluid mechanics to explain the decrease in flow of fluid in a tube when air bubbles are present. This happens because air is compressible, meaning that it can be squeezed into a smaller volume under pressure. When air bubbles enter a fluid system, they can become trapped in certain areas and create pockets of higher pressure. This in turn can restrict the flow of fluid in that particular area, resulting in a decrease in overall flow.

One common example of an air-lock in action is in plumbing systems. When air bubbles get trapped in a pipe, they can block the flow of water and cause issues such as reduced water pressure or a complete blockage. In order to prevent this, plumbers often use techniques such as bleeding the air out of the pipes to ensure smooth and consistent flow.

As for recommended references, there are many textbooks and online resources available that cover the air-lock concept in fluid mechanics. Some popular ones include "Fluid Mechanics" by Frank White and "Introduction to Fluid Mechanics" by John Finnemore and Joseph Franzini. Additionally, many universities and engineering schools offer courses specifically on fluid mechanics that cover this concept in depth.

I hope this helps to clarify the air-lock concept for you. Happy learning!