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Supply prepositions or conjunctions from the list



 

At, behind, below, from, in, of, over, through

1. In the impulse turbine the steam expands … the nozzles and its pressure does not alter as it moves over the blades.

2. In the reaction turbine the steam expanded continuously as it passes … the blades.

3. Thus there is gradually fall in the pressure during expansion … the atmospheric pressure.

4. The reaction turbine consists … a row of stationary blades and the following row of moving blades.

5. In an impulse turbine, the stage is a set of moving blades … the nozzle.

6. In a radial-flow turbine steam flows outward … the shaft to the casing.

7. In an extraction turbine steam is withdrawn from one or more stages, … one or more pressures, for heating, plant process, or feedwater heater needs.

8. In a steam turbine, the heat energy of steam is converted into kinetic energy by allowing it to expand … a series of nozzles.

 

 

5. Fill in the blanks to complete the following statements:

 

1. The two main types of steam turbines are ________ and ______.

2. Speed obtained in case of steam turbines may be as high as __________r.p.m.

3. The method of abstracting steam at certain section of turbine is known as _______.

4. In an impulse turbine the expansion of steam takes place in the ______ only, where the pressure decreases and velocity increases.

5. In an impulse turbine, the pressure of steam remains constant while it passes over the ….of the turbine.

6. In case of reaction steam turbine, the steam expands as it flows over the _________.

7. An actual reaction steam turbine is a combined ______ and_______ steam turbine.

8. In an actual reaction turbine, steam expands partly in stationary blades and partly as it flows over the _____ ______.

9. Degree of reaction is defined as the ratio of isentropic enthalpy drop in the moving blades to isentropic enthalpy drop in the ___________ of the reaction turbine.

10. In case of reaction turbines, since the steam expands continuously in both the fixed and moving blades, its relative velocity does not remain constant but _____________ due to the expansion of steam.

11. The velocity of a simple impulse steam turbine is too _____ for practical purposes and as such the speed has to be _______ by some suitable means.

12. The ______ turbine was the first impulse steam turbine successfully built in 1889.

6. For each of the following statements select the phrase given below:

 

(1) In a Parsons reaction turbine, the relative velocity at outlet is

(a) less than that at the inlet,

(b) greater than that at the inlet,

(c) equal to that at the inlet,

(d) equal to blade speed.

 

(2) In the impulse turbine the steam is expanded

(a) in nozzles,

(b) in blades,

(c) partly in nozzles and partly in blades,

(d) neither in nozzles nor in blades.

 

(3) In a condensing steam turbine the steam is exhausted

(a) at atmospheric pressure,

(b) below atmospheric pressure,

(c) above atmospheric pressure,

(d) at any pressure.

 

(4) De Laval turbine is a

(a) simple reaction turbine,

(b) simple impulse turbine,

(c) velocity compounded impulse turbine,

(d) pressure compounded impulse turbine.

 

(5) Steam turbine works on

(a) Rankine cycle,

(b) modified Rankine cycle,

(c) Bell-Coleman cycle,

(d) Carnot cycle.

 

(6) Parsons reaction turbine is basically

(a) an impulse-reaction turbine,

(b) a pressure compounded impulse turbine,

(c) a velocity compounded impulse turbine,

(d) a pure reaction turbine.

 

(7) Curtis turbine is basically

(a) a velocity compounded impulse turbine,

(b) a pressure compounded impulse turbine,

(c) a simple impulse turbine,

(d) an impulse-reaction turbine,

(e) a pure reaction turbine.

 

(8) Rateau turbine is basically

(a) a velocity compounded impulse turbine,

(b) a pressure compounded impulse turbine,

(c) an impulse-reaction turbine,

(d) a pure reaction turbine.

 

(9) The main advantage of reaction turbine as compared to impulse turbine is

(a) high blade speed,

(b) low blade speed,

(c) high efficiency,

(d) high output

 

(10) Most widely used method of governing steam turbine is

(a) throttle governing,

(b) nozzle control governing,

(c) by-pass governing.


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