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de laval turbine Explained

de Laval turbine at English => English (Websters 1913) Of Explained:

Turbine \Tur"bine\, n.
A form of steam engine analogous in construction and action
to the water turbine. There are practically only two distinct
kinds, and they are typified in the de Laval and the Parsons
and Curtis turbines. The

{de Laval turbine} is an impulse turbine, in which steam
impinges upon revolving blades from a flared nozzle. The
flare of the nozzle causes expansion of the steam, and
hence changes its pressure energy into kinetic energy. An
enormous velocity (30,000 revolutions per minute in the 5
H. P. size) is requisite for high efficiency, and the
machine has therefore to be geared down to be of practical
use. Some recent development of this type include turbines
formed of several de Laval elements compounded as in the
ordinary expansion engine. The

{Parsons turbine} is an impulse-and-reaction turbine, usually
of the axial type. The steam is constrained to pass
successively through alternate rows of fixed and moving
blades, being expanded down to a condenser pressure of
about 1 lb. per square inch absolute. The

{Curtis turbine} is somewhat simpler than the Parsons, and
consists of elements each of which has at least two rows
of moving blades and one row of stationary. The bucket
velocity is lowered by fractional velocity reduction. Both
the Parsons and Curtis turbines are suitable for driving
dynamos and steamships directly. In efficiency, lightness,
and bulk for a given power, they compare favorably with
reciprocating engines.