Q3Basic Mechanical Engineering

Question

Q.3 Define dryness fraction of steam.

Answer 1

In pure substance thermodynamics, when a working fluid exists strictly as a two-phase saturated liquid-vapor mixture (like wet steam), its exact thermodynamic state is rigorously defined by a dimensionless property called the dryness fraction or thermodynamic quality ( $x$ ).

x = \frac{m _{v}}{m _{v} + m _{l}} = \frac{m _{v}}{m _{total}}

Where $m_{v}$ rigorously represents the mass of the dry saturated vapor, and $m_{l}$ strictly represents the mass of the suspended saturated liquid droplets. For completely dry saturated vapor, $x = 1$ . For purely saturated liquid, $x = 0$ .

Q3Basic Mechanical Engineering

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