- #1
omberlo
- 14
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In the chapter relative to First law applied to flow processes, my book explains the "Flow Work" which appears in the energy balance, as work needed to push a volume of fluid into (and out of) the control volume. It also says that it's equal to pV, and then it is added to the internal energy U to become enthalpy H. My question is, why is such work pV, which in infinitesimal form would become (PdV + Vdp) and not just PdV?