Reconsider Prob. 14–83. Using EES (or other) software, investigate the effect of the runner outlet angle α₁ on the required net head and the output power. Let the outlet angle vary from –20° to 20° in increments of 1°, and plot your results. Determine the minimum possible value of α₁ such that the flow does not violate the laws of thermodynamics.

Data from Problem 14–83.

A Francis radial-flow hydro turbine is being designed with the following dimensions: r₂ = 2.00 m, r₁ =1.42 m, b₂ = 0.731 m, and b₁ = 2.20 m. The runner rotates at ṅ = 180 rpm. The wicket gates turn the flow by angle α₂ = 30° from radial at the runner inlet, and the flow at the runner outlet is at angle α₁ = 10° from radial (Fig. P14–83). The volume flow rate at design conditions is 340 m³/s, and the gross head provided by the dam is H_gross = 90.0 m. For the preliminary design, irreversible losses are neglected. Calculate the inlet and outlet runner blade angles β₂ and β₁, respectively, and predict the power output (MW) and required net head (m). Is the design feasible?

FIGURE P14–83

Transcribed Image Text:

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