1st Law of Thermodynamics (Open System)

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SUMMARY

The equation presented for the 1st Law of Thermodynamics for an Open System is incorrect. The correct formulation should include mass terms, specifically Δ(U + 1/2(mc^2) + mgz), rather than Δ(U + 1/2(c^2) + gz). This distinction is crucial for accurately representing energy changes in control volumes. The discussion highlights the importance of including mass flow rates in thermodynamic equations for open systems.

PREREQUISITES
  • Understanding of the 1st Law of Thermodynamics
  • Familiarity with open system thermodynamics
  • Knowledge of control volume analysis
  • Basic concepts of energy conservation in fluid mechanics
NEXT STEPS
  • Study the derivation of the 1st Law of Thermodynamics for open systems
  • Learn about control volume analysis in thermodynamics
  • Explore energy balance equations in fluid mechanics
  • Review mass flow rate calculations in thermodynamic systems
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Students and professionals in mechanical engineering, particularly those focusing on thermodynamics and fluid mechanics, will benefit from this discussion.

SherlockOhms
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Homework Statement


Is this equation correct for the 1st Law of Thermodynamics for an Open System (Control Volume):
Q - W + min(h + 1/2(c^2) + gz)in - mout(h + 1/2(c^2) + gz)out = Δ(U 1/2(c^2) + gz).


Homework Equations


None really.



The Attempt at a Solution


This isn't so much an assignment question as a possible discrepancy in the notes. I would've thought this Δ(U 1/2(c^2) + gz) should be Δ(U 1/2(mc^2) + mgz), am I correct in thinking that or not? Thanks.
 
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