Steam Nozzles and Turbines Online Quiz - ObjectiveBooks

Quiz Questions

01. The pressure at which the steam leaves the nozzle is known as back pressure.

02. The turbine, in which the general direction of the steam flow is parallel to the turbine axis, is called axial flow turbines

03. The blade velocity coefficient is ratio of relative velocity of steam at outlet tip of the blade to the relative velocity of steam at inlet tip of the blade.

04. The critical pressure ratio for initially dry saturated steam is more as compared to initially wet steam.

05. In a De-Laval impulse turbine, the nozzle is kept very close to the blades.

06. The ratio of the work delivered at the turbine shaft to the heat supplied is called overall thermal efficiency of turbine.

07. The velocity of steam, in reaction turbines, is increased in the fixed blades as well as in moving blades.

08. When the cross-section of a nozzle first increases from its entrance to throat, and then decreases from its throat to exit, it is not a convergent-divergent nozzle.

09. In a convergent divergent nozzle, the discharge depends upon the initial conditions of steam and the area of nozzle at throat.

10. The efficiency ratio is the ratio of total useful heat drop to the total isentropic heat drop.

11. In a single stage impulse turbine, the velocity of steam approaching nozzles is negligible.

12. The ratio of the cumulative heat drop to the isentropic heat drop is called reheat factor.

13. The Rankine efficiency depends upon total useful heat drop and total isentropic heat drop.

14. The discharge through a nozzle is maximum for a certain value of exit pressure. This pressure is known as critical pressure.

15. The pressure of steam, in reaction turbines, is reduced in the fixed blades as well as in moving blades.

16. The ratio of the energy supplied to the blades per kg of steam to the total energy supplied per stage per kg of steam is called mechanical efficiency.

17. In a nozzle, the effect of super-saturation is to increase the dryness fraction of steam.

18. In pressure compounding of an impulse turbine, the total pressure drop of the steam does not take place in the first nozzle ring, but is divided equally among all the nozzle rings.

19. During flow through a nozzle, no heat is supplied or rejected by the steam.

20. In velocity compounding of an impulse turbine, the expansion of steam takes place in a nozzle or a set of nozzles from the boiler pressure to condenser pressure.

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