Question

The masses of vapour and liquid are 3 kg and 2 kg, respectively in the mixture. Determine the dryness fraction of the liquid-vapour mixture
1. 1.5
2. 0.8
3. 0.6
4. 0.34

Answer 1

Correct Answer - Option 3 : 0.6

Concept:

Dryness fraction:

Dryness fraction (x) of steam is defined as the ratio of the mass of the dry steam to the total mass of both dry steam and liquid.

\(x = \frac{m_g}{m_f\; +\; m_g}\;\left( {0 \le x \le 1} \right)\)

where mg = mass of the dry steam or vapour and mf = mass of liquid.

Calculation:

Given:

m_g = 3, m_f = 2

\(x = \frac{m_g}{m_f\; +\; m_g}\)\(= \frac{{{3}}}{{{2}\; + \;{3}}} = 0.6\)

∴  The dryness fraction of the liquid-vapour mixture is 0.6