## steam nozzles and turbines

###### A nozzle is said to be a convergent nozzle
 A when the cross-section of the nozzle increases continuously from entrance to exit B when the cross-section of the nozzle decreases continuously from entrance to exit C when the cross-section of the nozzle first decreases from entrance to throat and then increases from its throat to exit D none of the above
 ANS: A - when the cross-section of the nozzle increases continuously from entrance to exit

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###### A turbine is said to have an axial discharge when the steam leaves the blade tip at __________ to the direction of the blade motion.
 A 60° B 90° C 180° D 270°
 ANS: B - 90°

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###### The flow through a nozzle is regarded as
 A constant volume flow B constant pressure flow C isothermal flow D isentropic flow
 ANS: D - isentropic flow

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###### The ratio of total useful heat drop to the total isentropic heat drop, is called
 A stage efficiency B internal efficiency C Rankine efficiency D none of these
 ANS: B - internal efficiency

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###### The pressure at which the steam leaves the nozzle is known as back pressure.
 A Correct B Incorrect
 ANS: A - Correct

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###### The discharge of steam in a convergent-divergent nozzle __________ after the throat (i.e. in the divergent portion of the nozzle)
 A remains constant B decreases C increases
 ANS: A - remains constant

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###### The rate of discharge through the nozzle __________ when the exit pressure is gradually reduced.
 A remains same B decreases C increases
 ANS: C - increases

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###### The velocity of steam leaving the nozzle (V) is given by (where K = Nozzle coefficient or nozzle efficiency, and hd = Enthalpy or heat drop during expansion of steam in a nozzle)
 A V = 44.72 hd √K B V = 44.72 K √hd C V = 44.72 √K hd D V = 44.72 K hd
 ANS: B - V = 44.72 K √hd

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###### In a nozzle, whole frictional loss is assumed to occur between
 A inlet and thoroat B inlet and outlet C throat and exit D all of these
 ANS: C - throat and exit

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###### The critical pressure ratio for initially wet steam is
 A 0.546 B 0.577 C 0.582 D 0.601
 ANS: C - 0.582

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