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The engine has the flywheel of mass 7 tons and the radius of gyration is 1.7 m. The fluctuation of energy is 55 kN-m. The mean speed of the engine is 150 rpm. What is the coefficient of fluctuation of speed?(a) 0.021(b) 0.011(c) 0.031(d) 0.041I got this question in an interview.Enquiry is from Flywheel in division Internal Combustion Engines of Automobile Engineering |
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Answer» RIGHT choice is (b) 0.011 Explanation: The FLUCTUATION of energy = ΔE, the mass of the flywheel = m, the RADIUS of GYRATION = k, the mean speed of the flywheel = N.ΔE = \(\frac{π^2}{900}\)*m*k^2*N*(N1-N2) = \(\frac{π^2}{900}\)*7000*1.7^2*150*(N1-N2) = 33277*(N1-N2) ⇒ 55000 = 33277*(N1-N2) ⇒ (N1-N2)=\(\frac{55000}{33277}\) = 1.652 RPM. Coefficient of fluctuation of speed = Cs = \(\frac{N_1-N_2}{N}\) = \(\frac{1.652}{150}\) = 0.011. |
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