Consider a steam turbine turbine in which the steam enters at 23.26 Mpa and 808
ID: 1940726 • Letter: C
Question
Consider a steam turbine turbine in which the steam enters at 23.26 Mpa and 808 K with a flow rate of 17.78 kg/s. The steam exists at a pressure of 5.249 kPa with a quality of 0.9566. Determine the power produced by the turbine and the isentropic efficiency.
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Consider a steam turbine turbine in which the steam enters at 23.26 Mpa and 808 K with a flow rate of 17.78 kg/s. The steam exists at a pressure of 5.249 kPa with a quality of 0.9566. Determine the power produced by the turbine and the isentropic efficiency. Any help will be greatly appreciated! Thanks in advance! will rate life saver for a solid answerExplanation / Answer
At 23.26 MPa and 808 K, from steam table:
h1 = 3311.65 KJ/Kg
and at P2 = 5.249 KPa and quality = 0.9566, from steam table:
h2 = hf@5.249 KPa + 0.9566 x hfg@ 5.249 KPa
= 142.5 + 0.9566 x (2420.5)
= 2457.95 KJ/Kg
W out = m_rate x (h1 - h2)
= 17.78 x (3311.65 - 2457.95)
= 15.178 KW = power developed by turbine = W actual
b) ISENTROPIC EFFICIENCY :
For isentropic work done :
s1 = s2
At 23.26 MPa and 808 K, from steam table:
s1 = 6.175 KJ/Kg.K
s2 = s1 6.175 KJ/Kg.K
At P2 = 5.249 KPa and s2 = 6.175 KJ/KG.K
h2' = 1886.66 KJ/Kg
W ideal = m_rate x (h1 - h2;)
= 17.78 x (3311.65 - 1886.66)
= 25.336 KW
isentropic efficiency = W actual / W ideal
= 15.178 / 25.336
= 0.599
= 59.9 %