An inward flow radial turbine (see Fig. P5.89) involves a nozzle angle, \(\alpha_{1}\), of \(60^{\circ}\) and an inlet rotor tip speed, \(U_{1}\), of \(6 \mathrm{~m} / \mathrm{s}\). The ratio of rotor inlet to outlet diameters is 1.8. The absolute velocity leaving the rotor at section (2) is radial with a magnitude of \(12 \mathrm{~m} / \mathrm{s}\). Determine the energy transfer per unit mass of fluid flowing through this turbine if the fluid is

(a) air,

(b) water.

Figure P5.89

V = 12 m/s Section (2) Section (1)