On a p-v-t-surface, the triple point and the critical point are seen respectively as
Line, line
Line, point
Point, line
Point, point
Which of the following coal variety has the highest calorific value
Anthracite
Bituminous
Lignite
Peat
The fuel mostly used in boilers is
Anthracite
Peat
Lignite
Bituminous
Efficiency of chimney draught is of the order of
8-10%
5-6%
2-3%
Less than 1%
Consider the following statements
de laval nozzle is a subsonic nozzle
supersonic nozzle is a converging passage
subsonic diffusion is a diverging passage
Which of these statements is/are correct?
1 and 2
2 and 3
1 alone
3 alone
Neglecting approach velocity, the theoretical velocity at nozzle exit equals
C=91.5
C=44.7
C=68.6
None of the above
Under ideal conditions, the velocity of steam at the outlet of a nozzle for a heat drop of 400 kJ/kg will be approximately
1200 m/s
900 m/s
600 m/s
The same as sonic speed
The cross-section of a nozzle is
Circular
Elliptical
Square
Rectangular
Which of these statements is/are correct?
1 and 2
2 and 3
1 and 3
1, 2 and 3
Choose the incorrect statement in the context of flow through a nozzle
Velocity increases at almost constant rate throughout the entire nozzle length
Specific volume of steam increases very rapidly during later part of expansion
Area decreases when specific volume increases less rapidly than increase in velocity
The ratio (velocity/specific volume) has minimum value at the nozzle throat
The critical pressure ratio for maximum discharge through a nozzle is given by
=
=
=
=
Where n is the value of exponent for the adiabatic expansion process.
For steam having inintial dryness fraction x, the value of exponent n for the adiabatic expansion through a nozzle can be worked out by using the Zeuner’s equation prescribed as
n=1.035+0.1x
n=1.35+0.1x
n=1.3+0.15x
n=1.15+0.1x
Which relation is valid for flow of superheated flow through a nozzle?
pv1.135=c
pv1.13=c
pv1.035=c
pv1.55=c
The value of critical pressure ratio for dry saturated steam is
0.525
0.546
0.578
0.627
Critical pressure ratio for superheated steam is
0.525
0.546
0.578
0.615
In a de-laval nozzle expanding super heated steam from 10bar to 0.1bar, the pressure at the minimum cross-section will be
3.3bar
5.46bar
5.78bar
8.2bar