(8)
This is the fundamental equation in the theory of turbines. In general,[7] w1 and w2, the tangential components of the water’s motion on entering and leaving the wheel, are completely independent. That the efficiency may be as great as possible, it is obviously necessary that w2 = 0. In that case
η = w1r1α / gH.
(9)
αr1 is the circumferential velocity of the wheel at the inlet surface. Calling this V1, the equation becomes
η = w1V1 / gH.
(9a)
This remarkably simple equation is the fundamental equation in the theory of turbines. It was first given by Reiche (Turbinenbaues, 1877).
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| Fig. 186. |
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| Fig. 189. |