Finding out compressibility of a fluid when bubbles are present?

In summary, Bobby is asking about the compressibility of a fluid with H2O bubbles present. He wonders if there is a way to calculate the mixture compressibility by looking up tabulated values for the gas compressibility and taking into account the mass fractions. However, it seems that the only option is to perform an experiment and measure the compressibility of the mixture. There may be existing work in this area, such as a patent for a method to determine non-dissolved gas in liquids.
  • #1
bzz77
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I want to know approximately how compressible a fluid can become when H2O bubbles are present. Does anyone know how to do this? Thanks.
 
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  • #2
bzz77 said:
I want to know approximately how compressible a fluid can become when H2O bubbles are present. Does anyone know how to do this? Thanks.

Will you please explain what are "H2O bubbles"? Thank you.

Bobbywhy
 
  • #3
Thanks for your response, Bobby.

I mean that if we have liquid and know its compressibility (it is approximately incompressible), then we add some gas bubbles to it (of known composition, let's assume H2O), then how can we calculate the mixture compressibility?

Is this a matter of looking up tabulated values for the gas compressibility at the temperature and pressure of interest, then summing the liquid and gas compressibilities, taking their mass fractions into account?
 
  • #4
H2O (water) does not form gaseous bubbles unless raised above its boiling point. Are you thinking of some other gas bubbles in water?

Compressibility is the fractional change in volume per unit increase in pressure. It seems reasonable to expect that if gas bubbles are added, then the volume would decrease more under the same pressure because gas is far more compressible.

There are not “look-up tables” for such mixtures. I think your only option would be to perform the experiment and measure the compressibility of the mixture.

Bobbywhy
 
  • #5
Thanks, Bobby. I'm thinking of a liquid that is not water, but that is essentially incompressible. it would be at temperatures high enough that water gas would be stable. I want to do some flow calculations and I'd like to get a rough idea of how compressible the liquid plus gas mixture would be compared to liquid only.

I was hoping there might be a rough way to calculate this, but it appears not. Anyway, thanks a lot.
 
  • #6
bzz77, There may be work already done in the area you are interested in. See this patent, for instance:

"Method and apparatus for the determination of non-dissolved gas in liquids
ABSTRACT
The method enabling the quick determination of non-dissolved or free gas in a liquid sample. Involves measuring the density of a liquid sample in a closed vessel, subjecting this sample to a reduced pressure and thereby expanding the "free" gas in the liquid sample. After this expansion has taken place, but before allowing dissolved gas to come out of solution, the volume is fixed and a second density measurement is taken."
http://www.google.com/patents/US4584866

Bobbywhy
 
  • #7
Thanks a lot, Bobby. I expected that this would be something done routinely, so it is interesting to know that it isn't.
 

1. What is compressibility and why is it important to measure it in fluids with bubbles?

Compressibility is a measure of how much a fluid's volume changes in response to changes in pressure. It is important to measure compressibility in fluids with bubbles because the presence of bubbles can significantly affect a fluid's compressibility, which can have implications for various applications such as oil and gas extraction, underwater acoustics, and even the performance of carbonated beverages.

2. How do you determine the compressibility of a fluid with bubbles?

To determine the compressibility of a fluid with bubbles, a common method is to perform a series of pressure-volume measurements on a sample of the fluid. This involves applying different pressures to the fluid and measuring the corresponding changes in volume. By plotting these measurements on a graph, the compressibility of the fluid can be calculated from the slope of the resulting line.

3. What factors can affect the compressibility of a fluid with bubbles?

The compressibility of a fluid with bubbles can be affected by various factors such as the size and number of bubbles present, the type of gas trapped in the bubbles, and the properties of the fluid itself (e.g. viscosity, density, etc.). Additionally, external factors such as temperature and pressure can also influence the compressibility of a fluid with bubbles.

4. Can the compressibility of a fluid change over time due to the presence of bubbles?

Yes, the compressibility of a fluid can change over time due to the presence of bubbles. As bubbles rise to the surface and burst, the gas they contain is released into the fluid, which can alter its compressibility. This is especially important in industrial processes where the presence of bubbles is constantly changing, such as in oil and gas pipelines.

5. How can knowledge of a fluid's compressibility with bubbles be useful in real-world applications?

Knowledge of a fluid's compressibility with bubbles can be useful in various real-world applications. For example, in the oil and gas industry, it can help predict the behavior of fluids during extraction processes and ensure the safety and efficiency of pipelines. In underwater acoustics, understanding the compressibility of seawater with bubbles is crucial for accurately interpreting sonar signals. It can also be useful in the production of carbonated beverages, where controlling the compressibility of the drink is important for maintaining its desired level of carbonation.

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