An impulse steam turbine has several pressure stages, each having a row of nozzles and a single ring of blades. The nozzle angle in the first stage is \( 20^{\circ} \) and the blade exit angle is \( 30^{\circ} \) with reference to the plane of rotation. The mean blade speed is \( 140 \mathrm{~m} / \mathrm{s} \) and the velocity of steam leaving the nozzles is \( 350 \mathrm{~m} / \mathrm{s} \). (a) Taking the blade friction factor as 0.85 and a nozzle efficiency of 0.9 , determine the work done in the stage per \( \mathrm{kg} \) of steam and the stage efficiency. (b) If the steam supply to the first stage is at \( 30 \mathrm{bar}, 250^{\circ} \mathrm{C} \) and the condenser pressure is \( 0.1 \mathrm{bar} \), estimate the number of stages required, assuming that the stage efficiency and the work done are the same for all stages and that the reheat factor is 1.05

Q #3 An impulse steam turbine has several pressure stages, each having a row of nozzles and a single ring of blades. The nozzle angle in the first stage is 20 and the blade exit angle is 30 with reference to the plane of rotation. The mean blade speed is 140m/s and the velocity of steam leaving the nozzles is 350m/s. (a) Taking the blade friction factor as 0.85 and a nozzle efficiency of 0.9 , determine the work done in the stage per kg of steam and the stage efficiency. (b) If the steam supply to the first stage is at 30bar,250C and the condenser pressure is 0.1 bar, estimate the number of stages required, assuming that the stage efficiency and the work done are the same for all stages and that the reheat factor is 1.05