On Mollier chart, free expansion, or throttling process from high pressure to atmosphere is represented by
Horizontal straight line
Vertical straight line
Straight inclined line
Curved line
Correct Answer :
A. Horizontal straight line
Related Questions
The isentropic enthalpy drop in moving blade is two-third of the isentropic enthalpy drop in fixed blades of a turbine. The degree of reaction will be
0.4
0.56
0.67
1.67
In reaction turbines, the axial thrust is due to
Pressure drop across the rotor
Change in axial velocity
Both (A) and (B)
None of these
Steam turbines may be classified according to
Direction of steam flow
Number of stages
Mode of steam action
All of these
100% efficiency of a thermal cycle cannot be achieved because of
Frictional losses
It is not possible to achieve 0°K temperature
Leakage
Non availability of ideal substance
In an impulse turbine
The steam is expanded in nozzles only and there is a pressure drop and heat drop
The steam is expanded both in fixed and moving blades continuously
The steam is expanded in moving blades only
The pressure and temperature of steam remains constant
The fire tubes in a Scotch marine boiler are
Horizontal
Vertical
Inclined
None of these
Which of the following statement is wrong?
Locomotive boiler is a water tube boiler
Water tube boilers are internally fired
Lamont boiler is a low pressure water tube boiler
All of the above
The number of drums in Benson steam generator is
One
Two
One steam drum and one water drum
No drum
Expansion ratio is the ratio of
Swept volume to the volume at cut-off
Clearance volume to the swept volume
Volume at cut-off to the swept volume
Swept volume to the clearance volume
On Millier chart, the constant pressure lines
Diverge from left to right
Diverge from right to left
Are equally spaced throughout
First rise up and then fall
Vacuum for reciprocating steam engines compared to steam turbines is
More
Equal
Less
Could be more or less depending on the size of plant
The maximum steam pressure in a Locomotive boiler is limited to
0.18 MN/m²
1.8 MN/m²
18 MN/m²
180 MN/m²
The pressure of steam in the engine cylinder at the beginning of the stroke is ________ the boiler pressure.
Equal to
Less than
Higher than
None of these
Willians line follows the law (where b = A constant representing the shape of the Willians line, a = Another constant i.e. no load consumption per hour, I.P. = Indicated power, and m = Steam consumption per hour)
I.P. = a × m + b
m = a + b × I.P.
I.P. = b × m + a
m = (b/I.P.) - a
Degree of reaction is defined as the ratio of
Heat drop in fixed blades to the heat drop in moving blades
Heat drop in moving blades to the heat drop in fixed blades
Heat drop in moving blades to the heat drop in fixed blades plus heat drop in moving blades
Heat drop in fixed blades plus heat drop in moving blades to the heat drop in moving blades
With increase in load, radiant superheater has
Drooping characteristic
Linear characteristic
Rising characteristic
Flat characteristic
The cylinder condensation or missing quantity may be reduced by
The efficient steam jacketing of the cylinder walls
Superheating the steam supplied to the engine cylinder
Keeping the expansion ratio small in each cylinder
All of the above
In a reaction turbine, when steam flows through the moving blades,
Pressure increases while velocity decreases
Pressure decreases while velocity increases
Pressure and velocity both decreases
Pressure and velocity both increases
A turbine is said to have an axial discharge when the steam leaves the blade tip at _________ to the direction of the blade motion.
60°
90°
180°
270°
While steam expands in turbines, theoretically the entropy
Remains constant
Increases
Decreases
Behaves unpredictably
An ideal regenerative cycle is
Equal to Carnot cycle
Less than Carnot cycle
More than Carnot cycle
Could be anything
A condenser where circulating water flows through tubes which are surrounded by steam, in known as
Surface condenser
Jet condenser
Barometric condenser
Evaporative condenser
The velocity of whirl at outlet for an axial discharge turbine is
Minimum
Maximum
Zero
None of these
In a velocity compounded impulse turbine, when steam flows through the second row of moving blades,
Velocity increases
Velocity decreases
Velocity remains constant
Pressure remains constant
The specific heat of superheated steam in kcal/kg is generally of the order of
0.1
0.3
0.5
0.8
The ratio of the workdone on the blades to the energy supplied to the blades, is called
Blading efficiency
Nozzle efficiency
Gross or stage efficiency
Mechanical efficiency
The efficiency of reaction turbine is maximum when (where α = Angle made by the absolute velocity V at inlet)
Vb = 0.5 V cosα
Vb = V cos α
Vb = 0.5 V² cosα
Vb = V² cosα
A condenser in a steam power plant
Increases expansion ratio of steam
Reduces back pressure of steam
Reduces temperature of exhaust steam
All of these
In a steam condenser, the partial pressure of steam and air are 0.06 bar and 0.007 bar respectively. The condenser pressure is
0.007 bar
0.053 bar
0.06 bar
0.067 bar
Hard coke is produced by carburisation of coal at
Atmospheric temperature
500-600°C
700-850°C
950-1100°C