Home › Previous year questions › GATE 2020 AE › Question 33GATE 2020 AE – Question 33 Propulsion · Turbomachinery: Axial compressors, work and compression, degree of reaction, multi-staging · 1 mark · Numerical answer
Air enters an axial-compressor rotor with zero pre-whirl and exits with whirl velocity 150 m/s. Blade speed is 200 m/s and cp = 1005 J/(kg K). Find stagnation-temperature rise in K, to 1 decimal place.
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Show answer and explanation Correct answer: 29.8 to 30.0
Explanation Euler’s rotor-work relation gives $\Delta h_0=U(C_{\theta2}-C_{\theta1})=200(150-0)=30000$ J/kg. With constant cp, $\Delta T_0=\Delta h_0/c_p=30000/1005=29.8507$ K, or 29.9 K.
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