1000 points 1 out of 5 attempts Assume the sumoundings to be

1000 points 1 out of 5 attempts Assume the sumoundings to be at 21°C. Assistance Check My Work Try Another 6 MPa View Hint 600°C Question Help 5.40 MW 50 kPa 154 m/s Steam enters an adiabatic turbine at 6 MPa, 6000C, and s6 mlsand leaves at References eBook & Resources Multipart Answer a P3 Ask me anything

Solution

From a 1st law energy balance on the system, by denoting entry condition as state 1 and exit as state 2 we get

m(h₁ + V₁² /2) = W_out + m(h₂ + V₂² /2)

W_out = m*[h₁ - h₂ + (V₁² - V₂²) /2]

From steam properties at P1 = 6 MPa and T1 = 600 deg C, we get specific enthalpy h1 = 3660 kJ/kg and specific entropy s1 = 7.17 kJ/kg-K

From steam properties at P2 = 50 kPa and T2 = 100 deg C, we get specific enthalpy h2 = 2680 kJ/kg and specific entropy s2 = 7.7 kJ/kg-K

We are given that V₁ = 86 m/s and V₂ = 154 m/s and W_out = 5.4 MW

Thus, 5.4*10⁶ = m*[3660*10³ - 2680*10³ + (86² - 154²) /2 ]

Mass flow rate m = 5.556 kg/s

For max. power output, W_rev,out = m*[(h1 - h2) + (KE₁ - KE₂) - T₀*(s1 - s2) ].......where KE is kinetic energy, T₀ = Ambient temp = 21 deg C = 294 K

W_rev,out = 5.556*[3660*10³ - 2680*10³ + (86² - 154²) /2 - 294*(7.17*10³ - 7.7*10³) ]

W_rev,out = 6.2658 MW = 6266 kW