Okay will do!
I’ll probably start with those same articles. They seem to know about it.
Unless you have some other sources about entropy that might help me learn about it in the way you do?
Simply put, entropy is a quantity representing the availability of the thermal energy in a system to be converted into work.
A rocket cannot possibly maintain constant entropy.
As stack writes falsely:
Rocket engines are considered Isentropic systems where entropy remains unchanged.
Isentropic nozzle flow
"Whenever a gas is forced through a tube, the gaseous molecules are deflected by the tube's walls. If the speed of the gas is much less than the speed of sound, the gas density will remain constant and the velocity of the flow will increase. However, as the speed of the flow approximates the speed of sound, compressibility effects on the gas are to be considered. The density of the gas becomes position dependent. While considering flow through a tube, if the flow is very gradually compressed (i.e. area decreases) and then gradually expanded (i.e. area increases), the flow conditions are restored (i.e. return to its initial position). So, such a process is a reversible process. According to the Second Law of Thermodynamics, whenever there is a reversible and adiabatic flow, constant value of entropy is maintained. Engineers classify this type of flow as an isentropic flow of fluids.”
So you see, a Nonisentropic process, like Free Expansion, does not apply to an Isentropic system. Apples and oranges.
...it is obviously written by someone trying to engage in double speak...
And stack, while he talks of the rocket engine, does
NOT want you to look behind the curtain containing the
rocket exhaust, which is where the meat and potatoes is at.
A rocket has a fixed amount of fuel and a fixed amount of potential energy.
Rockets have a fixed rate of discharge at any particular point of time.
Sooner or later, there is no more more potential energy available.
Therefore, rockets cannot maintain unchanged entropy when in operation.
And that process is not "reversible," nor can it possibly be "adiabatic," as described in stacks' ridiculous post, once initiated. Rockets experience no reverse flow of fluids or exhaust. The exhaust is supposedly taking place in the vacuum of outer space...again, where all the fakers want you to believe that gas, just because it is coming from a rocket, can somehow, someway...be different...but it, of course...cannot.
Gas released into a vacuum...does no work.