Steam at 1 MPa, 630.2 o C, expands in an insulated piston cylinder assembly to 0
ID: 1858332 • Letter: S
Question
Steam at 1 MPa, 630.2oC, expands in an insulated piston cylinder assembly to 0.01 MPa. Determine the maximum work (kJ) done during the process if the initial volume is 0.126 m3. answer is 281.1 ± 0.15%Steam at 1 MPa, 567.9oC, expands in a turbine to 0.01 MPa. If the process is isentropic, find the work per unit mass (kJ/kg) produced by the turbine answer is 1108.7 ± 0.2%
Steam at 1 MPa, 556.4oC, expands in a turbine to 0.01 MPa. If the process is isentropic, find the specific enthalpy (kJ/kg) at the exit of the turbine. answer is 2509.3 ± 0.1%
Steam at 1 MPa, 630.2oC, expands in an insulated piston cylinder assembly to 0.01 MPa. Determine the maximum work (kJ) done during the process if the initial volume is 0.126 m3. answer is 281.1 ± 0.15%
Steam at 1 MPa, 567.9oC, expands in a turbine to 0.01 MPa. If the process is isentropic, find the work per unit mass (kJ/kg) produced by the turbine answer is 1108.7 ± 0.2%
Steam at 1 MPa, 556.4oC, expands in a turbine to 0.01 MPa. If the process is isentropic, find the specific enthalpy (kJ/kg) at the exit of the turbine. answer is 2509.3 ± 0.1%
Explanation / Answer
From steam tables, at 1 MPa, 630.2 deg C, we get u1 = 3350 kJ/kg and s1 = 8.11 kJ/kg-K, v1 = 0.415 m3/kg
From steam table at s2 = s1 = 8.11 kJ/kg-K and P2 = 0.01 MPa, we get u2 = 2430 kJ/kg
mass m = V / v = 0.126 / 0.415 = 0.304 kg
w = u1 - u2 = 3770 - 2570 = 920 kJ/kg
W = 0.304*920 = 279.68 kJ
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At 1 MPa, 567.9 deg C, h1 = 3630 kJ/kg, s1 = 7.95 kJ/kg-K
At s = 7.95 kJ/kg-K, and P = 0.01 MPa, we get h2 = 2520 kJ/kg
w = h1 - h2 = 3630 - 2520 = 1110 kJ/kg
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At 1 MPa, 556.4 deg C, we get s = 7.92 kJ/kg-K
At s = 7.92 kJ/kg-K and P2 = 0.01 MPa, we get h2 = 2510 kJ/kg