Thermic Turbo Machines

• This is done in steam power plants, in which

combustion of coal is used to vaporize
steam and the thermal energy of the steam
is then converted to shaft work in a steam
turbine.
• The shaft turns a generator that produces
electricity. Nuclear power plants work on
the same principle, with uranium, and in
rare cases thorium, as the fuel.
Thermic Turbo Machines
• In all the methods mentioned, conversion of energy to usable forms
takes place in a. fluid machine, and in these instances they are power-
producing machines. There are also power-absorbing machines, such
as pumps, in which energy is transferred into a fluid stream.
Thermic Turbo Machines
• In both power-producing and power-absorbing machines energy
transfer takes place between a fluid and a moving machine part.
• In positive-displacement machines the interaction is between a fluid
at high pressure and a reciprocating piston. Spark ignition and diesel
engines are well-known machines of this class. Others include piston
pumps, reciprocating and screw compressors, and vane pumps.
Thermic Turbo
Machines

• Examples of power-producing
turbomachines are steam and gas
turbines, and water and wind
turbines. The power-absorbing
turbomachines include pumps, for
which the working fluid is a liquid,
and fans, blowers, and compressors,
which transfer energy to gases.
Thermic Turbo
Machines

• A turbomachine is a device where

mechanical energy, in the form of
shaft work, is transferred either to or
from a continuously flowing fluid by
the dynamic action of rotating blade
rows.
Thermic Turbo Machines
• In the first case, energy extracted from the flow is used to drive a rotating
component, generally called a rotor (bladed drum, bladed wheel or
collection of bladed wheels), driving on its turn a useful external load. The
machine may then be called shaft power delivering, or for short, power
delivering, but typically it is termed a turbine, irrespective of the fluid.
Possible fluids are:
• water: water turbine or hydraulic turbine
• steam (vapour): steam turbine
• air in natural wind: wind turbine
• gas produced by combustion of a fuel in pressurised air: gas turbine
• other fluid, as refrigerant in a cooling cycle: expansion turbine.
Thermic Turbo Machines
• In turbomachines energy transfer takes place between a continuously
flowing fluid stream and a set of blades rotating about a fixed axis.
The blades in a pump are part of an impeller that is fixed to a shaft.
• In an axial compressor they are attached to a compressor wheel. In
steam and gas turbines the blades are fastened to a disk, which is
fixed to a shaft, and the assembly is called a turbine rotor.
• Fluid is guided into the rotor by stator vanes that are fixed to the
casing of the machine. The inlet stator vanes are also called nozzles,
or inlet guide vanes.
Thermic Turbo Machines
Steam Turbines
• The prime mover in a steam power plant is a steam turbine that
converts part of the thermal energy of steam at high pressure and
temperature to shaft power.
• A turbine from which the steam leaves at quality near 90% is called a
condensing turbine.
• An extraction turbine has ports from which steam is extracted for
feedwater heating.
• An induction turbine receives steam at intermediate pressures for
additional power generation.
Steam Turbines
• In a noncondensing or backpressure turbine, steam leaves at
superheated conditions and the thermal energy in the exhaust steam
is used in various industrial processes.
• A well-designed combined heat and power plant generates
appropriate amount of power to drop the steam temperature and
pressure to values that meet the process heating needs.
Steam Turbines
• The turbines are said to be compounded when steam passes through
each of them in series.
• The highpressure (HP) turbine receives steam from the steam
generator.
• After leaving this turbine the steam is reheated and then enters an
intermediate-pressure (IP) turbine, also called a reheat turbine,
through which it expands to an intermediate pressure.
• After the second reheat the rest of the expansion takes place through
a low-pressure (LP) turbine, from which it enters a condenser at a
pressure below the atmospheric value.
 Low Pressure
High Pressure Turbine
Turbine

Intermediate
Pressure Turbine
Gas Turbines
• Major manufacturers of gas turbines produce both jet engines and
industrial turbines.
• The high powerto-weight ratio makes gas turbines particularly suited for
propulsion applications.
• The absence of reciprocating and rubbing members, in comparison with
internalcombustion engines, means fewer balancing problems and less
lubricating-oil consumption.
• Since the 1980s, gas turbines, with clean-burning natural gas as a fuel, have
also made inroads into electricity production.
• Their use in combined cycle power plants has increased the plant overall
thermal efficiency to just under 60%.
• They have also been employed for stand-alone power generation.
Gas Turbines
 Hydraulic Turbines
• In those areas of the world with large rivers, water
turbines are used to generate electrical power.
• Hydraulic Turbines have a row of blades fitted to the
rotating shaft or a rotating plate.
• Flowing liquid, mostly water, when pass through the
Hydraulic Turbine it strikes the blades of the turbine and
makes the shaft rotate.
• While flowing through the Hydraulic Turbine the velocity
and pressure of the liquid reduce, these result in the
development of torque and rotation of the turbine shaft.
• Hydraulic Turbines transfer the energy from a flowing
fluid to a rotating shaft. Turbine itself means a thing
which rotates or spins.
Hydraulic Turbines
• There are different forms of Hydraulic
Turbines in use depending on the
operational requirements.

• For every specific use a particular

type of Hydraulic Turbine provides
the optimum output.
Classification of Hydraulic Turbines: Based on
flow path
• Water can pass through the Hydraulic Turbines in different flow paths.
Based on the flow path of the liquid Hydraulic Turbines can be
categorized into three types.

• None of the Hydraulic Turbines are purely axial flow or purely radial
flow. There is always a component of radial flow in axial flow turbines
and of axial flow in radial flow turbines.
Classification of Hydraulic Turbines: Based on
flow path
• Axial Flow Hydraulic Turbines: This category of Hydraulic Turbines
has the flow path of the liquid mainly parallel to the axis of rotation.
Kaplan Turbines has liquid flow mainly in axial direction.
• Radial Flow Hydraulic Turbines: Such Hydraulic Turbines has the
liquid flowing mainly in a plane perpendicular to the axis of rotation.
• Mixed Flow Hydraulic Turbines: For most of the Hydraulic Turbines
used there is a significant component of both axial and radial flows.
Such types of Hydraulic Turbines are called as Mixed Flow
Turbines. Francis Turbine is an example of mixed flow type, in Francis
Turbine water enters in radial direction and exits in axial direction.
Classification of Hydraulic Turbines: Based on
pressure change
• One more important criterion for classification of Hydraulic Turbines
is whether the pressure of liquid changes or not while it flows
through the rotor of the Hydraulic Turbines. Based on the pressure
change Hydraulic Turbines can be classified as of two types.
Classification of Hydraulic Turbines: Based on
pressure change
• Impulse Turbine: The pressure of liquid does not change while
flowing through the rotor of the machine. In Impulse Turbines
pressure change occur only in the nozzles of the machine. One such
example of impulse turbine is Pelton Wheel.
• Reaction Turbine: The pressure of liquid changes while it flows
through the rotor of the machine. The change in fluid velocity and
reduction in its pressure causes a reaction on the turbine blades; this
is where from the name Reaction Turbine may have been derived.
Francis and Kaplan Turbines fall in the category of Reaction Turbines.
Wind Turbines

• Simply stated, wind turbines

work the opposite of a fan.
Instead of using electricity to
make wind—like a fan—wind
turbines use wind to make
electricity.
• The wind turns the blades,
which in turn spins a generator
to create electricity.
Wind Turbines
• The terms "wind energy" and "wind power" both describe the process by which
the wind is used to generate mechanical power or electricity. Wind turbines
convert the kinetic energy from the wind into mechanical power. This mechanical
power can be used for specific tasks (such as grinding grain or pumping water) or
a generator can convert this mechanical power into electricity.
• A wind turbine turns energy in the wind into electricity using the aerodynamic
force created by the rotor blades, which work similarly to an airplane wing or
helicopter rotor blade. When the wind flows across the blade, the air pressure on
one side of the blade decreases. The difference in air pressure across the two
sides of the blade creates both lift and drag. The force of the lift is stronger than
the drag and this causes the rotor to spin. The rotor is connected to the
generator, either directly (if it's a direct drive turbine) or through a shaft and a
series of gears (a gearbox) that speed up the rotation and allow for a physically
smaller generator.
Pumps, compressors,
fans and blowers
• Pumps, compressors, fans and blowers all
belong to a class of devices that use
mechanical work input to increase the
pressure and/or velocity of a fluid.
• Pumps are used for pressurizing liquids,
while compressors are used for
pressurizing gases.
• Fans and blowers are primarily used as
"air handlers" to move air through ducts
and equipment.