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russ_watters
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So what you are saying is that you can have air behave adiabatically in expansion and then isothermally in compression...and do compression in a diffuser? Please provide a reliable source that says that is possible and define, specifically, the properties of the air along the process; because it seems to me that you can't do compression isothermally without extracting heat from it...and do all this in an airstream where you aren't doing any work on it. Otherwise this would seem to be a clear-cut violation of conservation of energy...or perhaps two of them.pranj5 said:Not at all. There is a blower that is adding velocity of the air at low pressure. The nozzle will further enhance the velocity at the cost of enthalpy (both pressure an temperature) and after that a diffuser is used to convert that velocity into pressure.
What I can assume is that the fall in pressure and temperature inside the venturi is adiabatic but when the diffuser converts the velocity into pressure again, it's isothermal. Why? Because there is already an amount of gas at higher pressure in stock at that point that will stabilise the temperature during compression. In fact, the lower the temperature of the gas at higher pressure, lesser energy will be required to do the job.
What the nozzle will do is to convert a part of internal heat into motion which later will be converted to pressure by the diffuser. But, during the conversion process (from velocity to pressure), the temperature wouldn't rise as much like the adiabatic process.
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