Engineering Sciences
2017 · Paper 1
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Complete GATE XE 2017 Paper 1 overview, original pages and practice · Timed previous-paper practice
Questions 97–99 of 175. Imported answers require review unless explicitly marked reviewed.
Question 97
Open questionXE-ENAT2 marksNeeds review
In a steam power plant, steam is first expanded isentropically in a turbine from an initial condition of 100 bar and 500 °C to a pressure of 40 bar. Then the steam is reheated up to 500 °C at constant pressure. The steam is then expanded isentropically in another turbine up to a condenser pressure 0.01 bar. For steam, at 100 bar, 500°C: h = 3373.7 kJ/kg, s = 6.596 kJ/kg.K; at 40 bar, 500°C: h = 345.3 kJ/kg, s = 7.091 kJ/kg.K and at 0.01 bar: h_f = 29.3 kJ/kg, h_g = 2514.2 kJ/kg, s_f = 0.1059 kJ/kg.K, s_g = 8.9756 kJ/kg.K. The dryness fraction at the condenser inlet (up to 2 decimal places) is _________.
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Open questionXE-ENAT2 marksNeeds review
Air contains by volume 79% N₂ (molecular weight = 28 kg/kmol) and 21% O₂ (molecular weight = 32 kg/kmol). A stream of air flows at 32°C, 1 bar, at a rate of 2 m³/s and is mixed with another stream of O₂ flowing at 0.4 kg/s. The molecular weight of the mixture (up to 2 decimal places) is _________.
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You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answerQuestion 99
Open questionXE-ENAT2 marksNeeds review
Moist air enters a duct at a rate of 3 kg/s at 10°C, 80% relative humidity. The air is heated as it flows through the duct and exits at 30°C. No moisture is added or removed and the pressure of air in the duct is constant at 1 bar. The saturation vapor pressure (p_g) of H₂O at 10°C is 0.01228 bar. Specific enthalpy values of dry air at inlet and outlet of the duct are respectively 283.1 kJ/kg and 303.2 kJ/kg. The corresponding specific enthalpy values for water vapor are 2519.8 kJ/kg and 2556.3 kJ/kg. For steady state operation the amount of heat added to the moist air in kW (up to 2 decimal places) is _________.
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