I have a question regarding the principles of chemical engineering
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Suppose there is a compressed air storage tank, with a pressure of 5 bar inside the tank. A pipeline is connected to the storage tank, leading to the atmosphere. If the compressed air in the storage tank is released to the atmosphere, is the pressure at the interface between the pipe leading to the atmosphere and the atmosphere itself equal to atmospheric pressure?
Definitely not; it must be higher than atmospheric pressure!
In reality, it is certainly greater than atmospheric pressure, but in theoretical calculations, it is assumed that the pressure here is at atmospheric level.
The outlet pressure can be set to atmospheric pressure, with little error
When they are equal, the gas cannot be expelled; therefore, the pressure drop across the entire pipeline must be less than 5 bar for it to be able to be discharged
It’s definitely higher than atmospheric pressure; by how much depends on the flow rate of the exhaust gas.
It’s clearly atmospheric pressure. The pressure mentioned here is static pressure, and static pressure is definitely equal to atmospheric pressure. When the gas inside the pipe moves to this position, the static pressure head is converted into kinetic pressure head; in other words, those 5 bar of pressure are entirely converted into kinetic energy of the gas after overcoming the resistance losses. If frictional losses at the pipe outlet are not taken into account, the static head is 0, and the dynamic head is 5 bar
Agree with what was said on the seventh floor. According to the principles of chemical engineering, it is defined in such a way that only one of pressure and flow rate is taken into consideration.
This post was last edited by ai444099439 on 2011-6-1 10:26. If a pressure gauge is installed very close to the pipeline at the upstream end of the interface between the pipeline and the atmosphere, and if the pressure drop in the pipeline from the storage tank to the pressure gauge is 2 bar, what should be the reading on the pressure gauge?
After the gas is discharged, the pressure is completely lost; the pressure outside the pipe opening is atmospheric pressure, while it is not the same inside the pipe opening, so calculations are required.
There must be a process of change, right? Is it instantaneous? Is it still average? For instantaneous values, calculations are straightforward; but for average values, calculus is needed!