Free (mostly) Expansion of an Ideal Gas

In summary, the conversation discussed a problem involving an insulated container with a known volume and a heated air flow through a circular orifice. The initial temperature and pressure were given, along with the volume of the container and the area of the orifice. The rate of temperature change was also provided. The question was posed about crafting a formula for pressure and solving for the gauge pressure based on the given information. The person asking the question had to make assumptions and used the ideal gas and Bernoulli equation, resulting in a pressure value of 2.4E-6 mbar.
  • #1
Slader99
2
0
Hey All,

Had a problem to solve and wanted to know how others would approach it. Problem is as follows:

An insulated container of known volume has an orifice of know size. Container is filled with air and left to rest so that temperature and pressure is that of atmospheric surroundings. Container air is heated at a know rate which causes mass flow through orifice. What is the container pressure (gauge) resulting from the heating of said air?

Givens:
1) Initial temp is 300K and initial pressure 1atm.
2) Volume of container is 0.0033m^3
3) Orifice is circular of area 9.0E-6 m^2
4) Rate of temperature change is 1C/min

If you were to craft a formula for pressure as a function of rate of temperature change what would it look like? If you were to solve for pressure based on the givens above what would you get for Pgauge?

When I did the exercise I had to make more assumptions than I’m comfortable with. I ended up using the ideal gas & Bernoulli equation to arrive at a value in the range of 2.4E-6 mbar.


Thanks!
slader99
 
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  • #2
It is impossible to help this person without knowing what he has done in his own analysis.
 

FAQ: Free (mostly) Expansion of an Ideal Gas

1. What is the concept of free (mostly) expansion of an ideal gas?

The concept of free (mostly) expansion of an ideal gas refers to the process in which an ideal gas increases in volume without any external work being done on it. This typically occurs when the gas is allowed to expand into a larger container with a lower pressure.

2. How does free (mostly) expansion of an ideal gas differ from other types of gas expansion?

Unlike other types of gas expansion, free (mostly) expansion of an ideal gas does not involve any external work being done on the gas. This means that there is no change in the internal energy or temperature of the gas during the expansion.

3. What is the significance of the word "mostly" in free (mostly) expansion of an ideal gas?

The word "mostly" in free (mostly) expansion of an ideal gas indicates that the expansion is not entirely free and there may be some slight external work being done on the gas. This could be due to the gas expanding against a small amount of pressure or friction.

4. Does free (mostly) expansion of an ideal gas violate the laws of thermodynamics?

No, free (mostly) expansion of an ideal gas does not violate the laws of thermodynamics. This process is an example of an irreversible process, where energy is not conserved. However, this does not violate the laws of thermodynamics as these laws only apply to reversible processes.

5. What are some real-life examples of free (mostly) expansion of an ideal gas?

Some real-life examples of free (mostly) expansion of an ideal gas include the expansion of a gas in a spray can when the nozzle is pressed, the expansion of air in a balloon when it is released, and the expansion of air in a vacuum chamber when the pressure is suddenly reduced.

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