Chemical Engineering - Chemical Engineering Thermodynamics - Discussion

Discussion Forum : Chemical Engineering Thermodynamics - Section 9 (Q.No. 41)
41.
Steam undergoes isentropic expansion in a turbine from 5000 kPa and 400°C (entropy = 6.65 kJ/kg K) to 150 kPa) (entropy of saturated liquid = 1.4336 kJ/kg . K, entropy of saturated vapour = 7.2234 kJ/kg. K) The exit condition of steam is
superheated vapour.
partially condensed vapour with quality of 0.9.
saturated vapour.
partially condensed vapour with quality of 0.1.
Answer: Option
Explanation:
No answer description is available. Let's discuss.
Discussion:
3 comments Page 1 of 1.

Taisir said:   1 month ago
sf​<s2​<sg​⇒Steam is in the **wet (two-phase)** region at exit.
s2 ​ = sf ​ + x(sg​−sf​).

Substitute known values:
6.65 = 1.4336 + x(7.2234 − 1.4336)
6.65 = 1.4336 + x(5.7898).
x = 5.78986.65 − 1.4336
​= 5.78985.2164​≈0.901.

So, the quality is approximately 0.9 or 90% vapor, 10% liquid.

Ayush said:   5 years ago
Yes, I think Bharath is right.

Bharath said:   6 years ago
The correct answer is wet steam with quality 0.9 only then will the entropy be the same.
(3)

Post your comments here:

Your comments will be displayed after verification.