Which of the following process is represented by a horizontal line parallel to the abscissa of a Mollier-diagram?
Constant pressure
Constant temperature
Free expansion or throttling
Adiabatic expansion
Constant pressure lines in superheated region of the mollier diagram will have
A positive slope
A negative slope
Zero slope
Both positive and negative slope
Which one of the following statements is correct?
Pressure and temperature are independent during phase change
An isothermal line is also a constant pressure line in the wet vapour region
Entropy decreases during evaporation
The term dryness fraction id used to specify the fraction by mass of liquid in a mixture of liquid and vapour.
The triple point of a water is
54.35oK
13.84oK
216.55oK
273.16oK
For maximum discharge through a chimney of given height and cross-section, the ratio of absolute temperature of chimney gases to the absolute temperature of outside air is given by
Where m is the mass of air supplied per kg of coal
Which aspect is not correct with respect to a steam engine fitted on a locomotive unit?
Engine has a variable speed
Engine is supplied wet steam at about 10 kg/cm2 pressure
Spent up steam is exhausted to atmosphere
Wheels serve the purpose of flywheel
Choose the statement not applicable to steam engines in which expansion of steam from high pressure to back pressure takes place in a single cylinder
Large stroke length
High variation in tractive effort
Small leakage past the piston
High condensation of steam
What is the essential purpose of compounding of steam engine?
To have uniform turning moment variations
To effect saving in material weight
To reduce the temperature range per cylinder and arrest condensation
To reduce the leakage past valves
Which aspect is not true in the context of compounding of steam engines?
Expansion ratio decreases
Stroke length increases
Temperature range per cylinder is reduced
Uniform turning moment can be obtained by arranging the cylinders out of phase
High pressure and low pressure cylinders have a common piston rod, cross head, connecting rod and crank in a
Double acting steam engine
Woolfe compound steam engine
Receiver compound steam engine
Tendem compound steam engine
Point out the false statement about tandem type compound steam engine
Cylinders have a common piston rod, crosshead, connecting rod and crank
Axis of both the cylinders lie in the same straight line
Operation of both the cylinders is in phase
Small inertia force and uniform turning movement
In a woolfe type compound steam engine the cranks are placed………..a part
45o
90o
180o
270o
The turning moment will be uniform in
Double acting steam engine
Receiver type compound steam engine
Woolfe type compound steam engine
Tandem type compound steam engine
Which one of the following steam engine requires a smaller flywheel?
Simple type compound steam engine
Tandem type compound steam engine
Woolfe type compound steam engine
Receiver type compound steam engine
In cross compounding of steam engine
The cylinders are arranged side by side
The cylinders have common piston rod, connecting rod and crank
The cranks are 180 degree apart
A heavy flywheel is needed to even out the turning moment variation