Calculate the turbine specific speed of the turbine in Prob. 14–86E using customary U.S. units. Is it in the normal range for a Francis turbine? If not, what type of turbine would be more appropriate?

Data from Problem 14–86E

A Francis radial-flow hydroturbine has the following dimensions, where location 2 is the inlet and location 1 is the outlet: r₂ = 6.60 ft, r₁ = 4.40 ft, b₂ = 2.60 ft, and b₁ = 7.20 ft. The runner blade angles are β₂ = 82° and β₁ = 46° at the turbine inlet and outlet, respectively. The runner rotates at ṅ = 120 rpm. The volume flow rate at design conditions is 4.70 × 10⁶ gpm. Irreversible losses are neglected in this preliminary analysis. Calculate the angle α₂ through which the wicket gates should turn the flow, where α₂ is measured from the radial direction at the runner inlet (Fig. P14–83). Calculate the swirl angle α₁, where α₁ is measured from the radial direction at the runner outlet (Fig. P14–83). Does this turbine have forward or reverse swirl? Predict the power output (hp) and required net head (ft).

FIGURE P14–83

Transcribed Image Text:

I 1 1 1 1 V2.1 A 1 1 T V₂.n V₁ (1) Control volume V₁.1 VI. 1