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What is the difference between specific enthalpy and specific total enthalpy in the context of fluid flow?

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Total enthalpy is defined as the static enthalpy (or "plain" enthalpy) plus the kinetic energy, i.e.:

$$ h^\circ = h + \frac{v^2}{2} $$

In other words, the total enthalpy is the enthalpy that the fluid would have if it would be brought to halt by an adiabatic process (i.e. w/o heat transfer), thus converting the kinetic energy into enthalpy (pressure energy plus internal energy: the ratio among them is determined by the entropy production).

Such a conversion is actually happening in some real devices, e.g. at the exit of a final compressor stage, where kinetic energy is converted into pressure to avoid it being wasted due to turbulent dissipation.

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  • $\begingroup$ What exactly do you mean by arresting the flow? $\endgroup$ – user29463 Jul 18 at 15:30
  • $\begingroup$ @user29463 I mean bring it to a halt. I've edited the answer in a hope it will be clearer. $\endgroup$ – El_Monto Jul 19 at 8:39

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