Full load is supplied by the turbine shaft when the diameter of jet

Civil UPSC ESE Exam Solution 2021

UPSC ESE Exam Solution 2021 for Civil Engineering UPSC ESE 2021 GS Paper 1 download exam paper from telegram https://telegram.me/civil_experiences

A full load is supplied by the turbine shaft when the diameter of the jet issuing from the nozzle is 150 mm. If the load suddenly drops to 36% of the full load, what diameter of the jet should be attained by regulating the spear rod?

[A] 15 mm
[B] 45 mm
[C] 90 mm
[D] 180 mm

ANSWER= [C] 90 mm

Detailed Solution for Civil Engineering Exam

Upon change in load: discharge is varied by varying the area of jet

Q1 = Q

Velocity of jet remains constant.

At full load; d=d1 =150mm

Q2 = 0.36Q

AT 36% of full load, d = d²

Q = A * V1 = (π/4)d² * V1

V1 = constant, Q ∝ d²

Q²/Q¹ = (d2/d1)²

0.36 = (d2/150)²

d²/150 = 0.6

d² = 90 mm