TURBOMACHINERY: INTRODUCTION
IST, 2014-15
Turbomachinery in moderm industrial civilization
Steam turbines are at the heart of central station power plants,
whether fueled by coal or uranium;
Gas turbines and axial compressors are key components of jet
engines;
Aeroderivative gas turbines are used to generate electricity, with
natural gas as fuel, and to drive centrifugal and volumetric
compressors for transmitting natural gas across continents;
Blowers and fans are used for mine and industrial ventilation;
Large water pumps (often driven with steam turbines) are used
for water supply and in sanitation plants for wastewater cleanup;
Hydraulic turbines generate electricity from water stored in
reservoirs, and wind turbines do the same from the flowing wind.
Definition of a turbomachine
Turbomachines: devices in which energy is
transferred either to, or from, a continuosly
flowing fluid by the dynamic action of one or
more moving blade rows.
Two main categories: those that absorb power
to increase fluid pressure (fans, compressors and
pumps); and those that produce power by
expanding fluid to a lower pressure or head
(wind, hydraulic, steam, and gas turbines).
Categories according flow path
Axial flow turbomachine: the path of the through-flow is
wholly or mainly parallel to the axis of rotation.
Radial flow turbomachine: the path of the through-flow
is wholly or mainly in a plane perpendicular to the
rotation axis.
Mixed flow turbomachines: both radial and axial
velocity components of the through-flow are present in
significant amounts.
Tangential flow turbomachine: the path of the throughflow is mainly in the tangential direction.
Other categories
Turbomachines are further categorized as:
Open
or unducted;
Closed or ducted.
Turbomachines are further categorized as:
Impulse:
pressure changes are absent in the flow
through the rotor;
Reaction: pressure changes are present in the flow
through the rotor.
Early turbomachinery
Around 70 B.C. Romans introduced paddle-type water
wheels (pure impulse) for grinding grain.
62 B.C. Hero (from Greece) devised the first steampowered engine, the aeolipide, a pure reaction machine.
1705 Denis Papin published full descriptions of centrifugal
blowers and pumps.
1737-53 Bernard Forest de Belidor described
waterwheels with curved blades (percursors of Francis
turbines).
1752 John Smeaton in the UK (1724-1792) study
turbomachinery by model testing showing efficiencies
exceeding 60%.
Early turbomachinery
1754 Leonhard Euler (1707-1783) published the
Euler turbomachines equation.
1818-1900 pump production in USA and Europe
1875 J. B. Francis (USA) developed a highefficiency radial-inflow turbine (Francis turbine).
1878 L. G. Pelton (USA) developed the partialadmission impulse water turbine (Pelton turbine).
1910 Victor Kaplan (Czech Republic) designed a
high efficiency axial flow water turbine (Kaplan
turbine).
Early turbomachinery
1875 Osborne Reynolds (UK) axial flow steam turbine 12000
rpm.
1854 - 1931 Charles Parsons (UK) made major impact in steam
turbine design: 1884 - 10 HP, 18000 rpm machine; 1897 2000
HP, 2000rpm for naval propulsion; 1912 25 MW turbine for
Chicago Power Station; 1925 50 MW steam turbine, with a plant
thermal efficiency of 30%.
1898 Carl Laval 30000rpm steam turbine with convergentdivergent nozzle.
1899 Charles Parson (UK): 81 stages axial flow compressor; 70%
efficiency (later developement related to gas turbines design).
1929 Frank Whittle (UK): Gas turbine
EXAMPLES
Three Stage Steam Turbine (150 MW)
Steam turbine
Gas turbine (42MW)
Super-charger
Jet engines
One-stage Centrifugal Pump
Seven-stage centrifugal compressor
Six-stage centrifugal compressor
Multi-stage centrifugal compressor
Two-stage centrifugal compressor
Typical centrifugal compressor impellers
Turbocharger
Francis turbine
Spiral
casing
runner
Guide vanes
draft
tube
Kaplan turbine
Electrical
generator
Blade angle can be
controlled
spiral
casing
Guide
vanes
runner
Large Pelton turbine
Vertical axis
6 jets (6 nozzles)
The Darrieus vertical-axis wind turbine
Invented in 1925 by F.M. Darrieus (France). Usually 2 or 3 rotor blades.
Developped in USA and Canada 1970s to 1990s in competition with the
horizontal-axis wind turbine.
The modern horizontalaxis wind turbine
