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The main aim of my question is

Known parameters are:

1. Pressure inside the gas tank.

2. Dimension and shape of the gas tank.

3. Temperature in and outside the gas tank.

4. Volume of gas inside the gas tank.

5. Density of gas

Assumptions that can be made is:-

1. The gas tank is cylindrical in shape.

2. The valve is located exactly at the bottom of the gas tank (height of the valve from the bottom is zero).

3. The valve is completely open with out any regulators( etc.) in the valve.

4. Size of the opening is fixed from which the gas is coming out.

Some ideas that I got regarding this situation are:

1. The above situation will keep taking place until the pressure inside the gas tank gets equal to the atmospheric pressure.

2. The flow rate of the gas coming out of the gas tank will decrease with the decrease in pressure inside the gas tank.

3. It could be similar to the case of unsteady flow of fluids.

I have tried this equation below as a start but I know this doesn't feel right to calculate the time.

Since we know

Flow rate = Volume / Time

so changing sides

Time = Volume / Flow rate

So please anyone if you have an idea to find out time taken by a gas tank in emptying it into atmosphere it might be helpful. Also if you get anything regarding in the case of liquids ( or fluids) it might be helpful too.

The following things that I have already seen before posting this thread which are not much helpful are:

https://www.physicsforums.com/threads/how-long-will-it-take-for-a-gas-tank-to-empty.828527/

https://www.elgas.com.au/blog/2042-how-do-i-calculate-the-lpg-propane-consumption-per-hour

(this link below was helpful but the calculations were done in case of liquids)

https://www.haywardflowcontrol.com/images/flowcontrol/PDF/VessTime.pdf

**to find time taken by gas filled tank while emptying (from full to zero) it into atmosphere?**__I require a set of equations which might be used in the calculation of such a situation.__Known parameters are:

1. Pressure inside the gas tank.

2. Dimension and shape of the gas tank.

3. Temperature in and outside the gas tank.

4. Volume of gas inside the gas tank.

5. Density of gas

Assumptions that can be made is:-

1. The gas tank is cylindrical in shape.

2. The valve is located exactly at the bottom of the gas tank (height of the valve from the bottom is zero).

3. The valve is completely open with out any regulators( etc.) in the valve.

**No regulation is being made to the flow rate,**__flow rate is not constant.__4. Size of the opening is fixed from which the gas is coming out.

Some ideas that I got regarding this situation are:

1. The above situation will keep taking place until the pressure inside the gas tank gets equal to the atmospheric pressure.

2. The flow rate of the gas coming out of the gas tank will decrease with the decrease in pressure inside the gas tank.

3. It could be similar to the case of unsteady flow of fluids.

I have tried this equation below as a start but I know this doesn't feel right to calculate the time.

Since we know

Flow rate = Volume / Time

so changing sides

Time = Volume / Flow rate

So please anyone if you have an idea to find out time taken by a gas tank in emptying it into atmosphere it might be helpful. Also if you get anything regarding in the case of liquids ( or fluids) it might be helpful too.

The following things that I have already seen before posting this thread which are not much helpful are:

https://www.physicsforums.com/threads/how-long-will-it-take-for-a-gas-tank-to-empty.828527/

https://www.elgas.com.au/blog/2042-how-do-i-calculate-the-lpg-propane-consumption-per-hour

(this link below was helpful but the calculations were done in case of liquids)

https://www.haywardflowcontrol.com/images/flowcontrol/PDF/VessTime.pdf

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