Week 3 Q2 (ENGR5003) - Revisica

Week 3 Q2Exercise sheetCurrent spec2:120 min

ENGR5003 Week 3 workshop sheet Q2

5 kg of saturated steam at $150\ ^\circ\mathrm{C}$ is compressed until the pressure doubles.

Formulas you may need

Wet steam: $v = (1 - x)v_f + xv_g$ , $h = (1 - x)h_f + xh_g$ (on the formula sheet)
Dryness fraction: $x = \dfrac{h - h_f}{h_g - h_f}$ (on the formula sheet)
Constant-pressure heat for a closed system: $Q = m\Delta h$ (learn this: $Q = \Delta U + p\Delta V = \Delta H$ )

(a)
What is the initial volume of steam?
V1 =m^3
(b)
What is the dryness fraction after compression, given that this was an isenthalpic compression?
x2 =
(c)
What is the compression ratio $\left(\dfrac{V_1}{V_2}\right)$ ?
V1/V2 =
(d)
The steam cools back to $150\ ^\circ\mathrm{C}$ , how much heat is dissipated?
Q =kJ
First

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