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y velocidades de hasta 2300 rpm. Tambibn se
disefiaron y construyeron turbinas de caidas muy
bajas.
A pesar de1 &xito recogido por las turbinas
Fourneyron, carecian de flexibilidad y ~610 eran efi-
cientes en una gam limitada de condiciones de opera-
ci6n. Este problema fuk aborada or Hoyd y Boyden
(1804-79). Su trabajo evolucion6 al concept0 de un
motor de flujo hacia dentro debido a James B. Fran-
cis (1815-912). La moderna turbina Francis es el
resultado de esta linea de desarrollo. Al propio
tiempo, 10s ingenieros europeos abordaron la idea de
las maquinas de flujo axial, que hoy estin represen-
tados por las turbinas a “hGlice” de1 tipo Kaplan.
Al igual que las ruedas Belidor de cubes de eje ver-
Gcal evolucionaron en las modernas turbinas de reac-
ci6n de1 tipo Francis y Kaplan, el desarrollo de la
rueda hidrgulica cksica, de eje horizontal, alcanz6 su
punto culminante con la introducci6n de la turbina a
impulsos. Las simientes de1 desarrollo fueron plan-
tadus por Poncelet en 1826 con su descripci6n de 10s
criterios para una rueda hidrkulica eficiente. Estas
ideas fueron promovidas por un grupo de ingenieros
californianos a fines de1 Siglo XIX, uno de 10s cuales
fue Lester A. Pelton (1829-1908), cuyo nombre se ha
dado a la rueda Pelton, un chorro o chorros de ague
que inciden en una serie de cubes especialmente con-
figurzdos, espaciados a poca distancia entre si
alrededor de la periferia de una rueda. Asi, puce,
puede afiimarse que las turbinas de velocidad
relativamente elevada de la clase Francis y Kaplan
tienen sus origenes en las ruedas de cubes de eje ver-
tical de Belidor, mientras que la rueda Pelton puede
considerarse coma la evluci6n directa de la rueda
cient over a narrow range of operating condi-
tions. This problem was addressed by Hoyd and
Boyden (1804-79). Their work evolved into the con-
cept of an inward flow motor due to James B.
Francis (181592). The modern Francis turbine is
the result of this line of development. At the
same time, European engineers addressed the
idea of axial flow machines, which today are
represented by “propeller” turbines of the Kaplan
type. Just as the vertical axis tub wheels of Belidor
evolved into modern reaction turbines of the
Francis and Kaplan type, development of the
classical, horizontal axis water wheel reached its
peak with the introduction of the impulse turbine.
The seeds of development were sown by Poncelet
in 1826 with his description of the criteria for an
efficient water wheel. These ideas were
cultivated by a group of California engineers in
the late 19th century, one of whom was Lester A.
Pelton (1829-1908), whose name is given to the
Pelton wheel, a jet or jets of water impinging on
an array of specially shaped buckets, closely
spaced around the periphery of a wheel. Thus, it
can be said that the relatively high speed tur-
bines of the Francis and Kaplan type trace their
roots to the vertical axis tub wheels of Belidor,
whereas the Pelton wheel can be considered as a
direct development of the more familiar horizon-
tal axis water wheel. In over 250 years of develop-
ment, many ideas were tried, some were rejected
and others were retained and incorporated in the
design of the hydraulic turbine as we know it to-
day. This development has resulted in highly effi-
cient devices, as high as 95 per cent, which, in
hidraulica de eje horizontal m& conocida. En el curso terms of design concept, fall into roughly three
de 250 ties de desarrollo, se ensayaron muchas categories. The rest of this paper is devoted to a
ideas, algunas fueron rechazadas y otras mantenidas review of the principles of operation, the
e incorporadas en el diseiio de la turbina hid&&a classifica’;ion and selection of turbines for given
tal coma la conocemos hoy. Esta labor de desarrollo operating conditions and a review of performance
ha resultado en &spositivos sumamenk efi&nks, de characteristics and operational limitations. Most
has’@ 95 por ciento de eficiencia, que, en t&rmix?ou of our development effort has been placed on
de1 concept0 de disefio, caen generalmente dentro de large turbines, small turbine technology con-
tres categorias. El resto de este estudio esti sisting chiefly of scaling down larger turbines.
dedicado a analizar 10s principios de operaci6n, la This paper attempts to review the validity of this
clasificaci6n y selecci6n de las turbinas para deter- concept and attempts to focus on some needs
minadas condiciones operativas, y un ex&men de las for improvement.
caracteristicas de desempefio y limitaciones Because of the limitations on time for prepara-
operativas. La mayor park de nuestra labor de tion, this paper is necessarily more tutorial than
desarrollo has estado relacionada con turbinas was originally envisioned. Many manufacturers of
grandes en tanto que la tecnologia de las turbinas pe- small equipment were contacted, but only a
quefias ha consistido principaimente en una copia en handful answered our inquiries at the time this
miniatura de las twbmas mayores. En este estudio paper went to press.
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