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Question No. 33 • A steam turbine receives steam at pressure 20 bar and superheated to 3025 KJ/kg. The exhaust pressure is 0.07 bar and the expansion of steam takes place isentropically to 2101 KJ/kg. The heat supplied to boiler is 2860 kJ/kg. calculate the thermal efficiency of power plant.?
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Question No. 33 • A steam turbine receives steam at pressure 20 bar an...
Thermal Efficiency of Power Plant:

Given data:
- Inlet pressure (P1) = 20 bar
- Inlet steam superheated enthalpy (h1) = 3025 KJ/kg
- Exhaust pressure (P2) = 0.07 bar
- Isentropic expansion enthalpy (h2s) = 2101 KJ/kg
- Heat supplied to boiler (Q) = 2860 KJ/kg

Calculations:
1. Determine the outlet steam enthalpy (h2) using isentropic expansion process:
- h1 - h2s = (Cp)avg * (T1 - T2s)
- Assuming steam to be an ideal gas, Cp = 2.1 KJ/kg-K
- T1 = T2s (isentropic process)
- h2 = h1 - (Cp)avg * (T1 - T2s) = 2508.7 KJ/kg

2. Determine the work done by the turbine (W):
- W = h1 - h2 = 516.3 KJ/kg

3. Determine the heat rejected by the turbine (Q2):
- Q2 = h2 - h3 = h2 - hf2 = 2190.3 KJ/kg
- Assuming steam to be a saturated liquid at P2, hf2 = 191.6 KJ/kg

4. Determine the thermal efficiency (η):
- η = (W / Q) * 100% = (516.3 / (2860 - 2190.3)) * 100% = 27.1%

Explanation:
The given data is used to calculate various parameters including the outlet steam enthalpy, work done by the turbine, heat rejected by the turbine, and thermal efficiency of the power plant. The calculations are based on the first law of thermodynamics and the steam tables. The thermal efficiency of the power plant indicates the percentage of heat energy supplied to the boiler that is converted into useful work. The higher the thermal efficiency, the better the performance of the power plant.
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Question No. 33 • A steam turbine receives steam at pressure 20 bar and superheated to 3025 KJ/kg. The exhaust pressure is 0.07 bar and the expansion of steam takes place isentropically to 2101 KJ/kg. The heat supplied to boiler is 2860 kJ/kg. calculate the thermal efficiency of power plant.?
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Question No. 33 • A steam turbine receives steam at pressure 20 bar and superheated to 3025 KJ/kg. The exhaust pressure is 0.07 bar and the expansion of steam takes place isentropically to 2101 KJ/kg. The heat supplied to boiler is 2860 kJ/kg. calculate the thermal efficiency of power plant.? for Mechanical Engineering 2024 is part of Mechanical Engineering preparation. The Question and answers have been prepared according to the Mechanical Engineering exam syllabus. Information about Question No. 33 • A steam turbine receives steam at pressure 20 bar and superheated to 3025 KJ/kg. The exhaust pressure is 0.07 bar and the expansion of steam takes place isentropically to 2101 KJ/kg. The heat supplied to boiler is 2860 kJ/kg. calculate the thermal efficiency of power plant.? covers all topics & solutions for Mechanical Engineering 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for Question No. 33 • A steam turbine receives steam at pressure 20 bar and superheated to 3025 KJ/kg. The exhaust pressure is 0.07 bar and the expansion of steam takes place isentropically to 2101 KJ/kg. The heat supplied to boiler is 2860 kJ/kg. calculate the thermal efficiency of power plant.?.
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