Pocketbook of Useful Formulæ and Memoranda
for Civil and Mechanical Engineers

539 OF ENGINEERING FORMULÆ. High-pbessübe Turbines—Foukneyeon’s. h = Head of water in feet. Q — Quantity of water in cube feet per second. P = Horse-power. D = Internal diameter of turbine in feet. E = External „ „ V = Velocity of turbine at periphery in feet per second. N — Number of buckets. n = Number of guides. d — Depth of orifices in feet. A = Area of sum of orifices in square feet. V = 6'6 kJ h. *D = a/—• Q = 12-67 - • *Jh h P = -079 QÅ. A = — • E = 1 • 2 D when D is more than 6 feet. E = 1-4 Djwhen D is less than 6 feet. tN = 24 kJ D. n = N, when N is less than 24. N n = —, when N exceeds 24. Sectional area of supply-pipe = 0'4 Q. * In extreme cases of very high falls the diameter given by this formula may be increased. t Fourneyrpn’s rule for the number of buckets is the constant number 36, irrespective of the size of the turbine.