JONVAL

FRANCE (see also List of Individuals)

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.. 1804 Vaudres/F - 12.1.1844 Mulhouse/F

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Until the first decades of the 19th century, energy production was mainly furnished by windmills. The first development towards modern fluid machinery was the famous 1759 paper by John Smeaton (1724-1792). For a 2 feet diameter water wheel the effects produced by water velocity, hydraulic head and wheel speed with an undershot wheel arrangement were measured. His wheels were in cast iron instead of wood to improve stability and longevity. In the 1820s, Jean-Victor Poncelet (1788-1867) proposed curved wheel paddles and shock-free water entry into the compartments to increase efficiency to 65% of the undershot water wheel. In 1826, he proposed an inward-flow radial turbine. Later James B. Francis (1815-1892) added steady guide vanes to provide shockless water entry to the runner and minimum exit velocity from it.

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In 1824 Claude Burdin (1788-1873) proposed the free efflux turbine in which a vertical axis carries a runner with curved blades through which the water is issued almost tangentially. Burdin was unable to surmount the practical difficulties involved in making a satisfactory working turbine, yet his pupil Benoît Fourneyron (1802-1867) succeeded in 1827. His turbine had an efficiency of some 75% with pressure heads of up to 110 m. Later, the draft tube was added to turbines resulting in an addition of 6% in efficiency. Nicolas Joseph Jonval proposed in 1841 the axial-flow turbine; water passing through such turbines remained at about the same distance from the axis such that flow was practically unaffected by centrifugal force. The important improvement of Jonval was to divide the wheel into concentric compartments, so that governing at low loads functioned separately. An improved version of the Jonval turbine was presented by James Thomson (1822-1892) with his inward-flow turbine around 1860. Few biographical facts are known of Jonval, whose life was too short for unknown reasons.

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_{Anonymous (1867). Henschel-Turbine. Zeitschrift des Vereins Deutscher Ingenieure 11(8): 488. Anonymous (2004). Acte de décès de Nicolas-Joseph Jonval. Mairie: Mulhouse.}

_{Armengaud, A. (1858). Turbine en dessus, dite turbine Jonval-Koechlin. Traité théorique et pratique des moteurs hydrauliques: 346-361. Armengaud: Paris.}

_{Burstall, A.F. (1963). A history of mechanical engineering: 243-285. Faber and Faber: London. Haton, G.O. de la Goupillière (1902). Moteurs hydrauliques. La mécanique à l'Exposition de 1900 12: 8-61. P}

_{Jonval, N.J. (1841). Système de machines hydrauliques, dit veine virtuelle, turbine Jonval.}

_{Brevet d'invention: Paris.}