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QUESTION 1 A velocity-compounded, two-stage impulse gas turbine has two rows of moving blades separated by a row of fixed blades. The inlet and outlet angles for the fixed blades are 36° and 17° respectively. The inlet and outlet angles for the first row of moving blades are equal. The velocity of the gas at the inlet to the second stage is 2,2 times the average blade velocity. The mass flow rate of the gas is 62 kg/s. The inlet and outlet angles for the second row of moving blades are equal. There is a 4% loss of velocity across all blades due to friction. 1.1 Use a length of 40 mm for the average blade velocity and construct velocity diagrams for the turbine. Indicate the lengths of all lines in mm, as well as the magnitude of all angles, on the diagrams. (10) 1.2 Calculate the scale if the relative velocity of the gas at the inlet to the first stage is 526 m/s. E (1) 1.3 From the diagrams determine: 1.3.1 The magnitude of the angle at which the gas leaves the turbine (1) 1.3.2 The nozzle velocity of the gas in m/s (1) @ @ @ na 1.3.3 The velocity of the gas leaving the first stage in m/s (1) 1.3.4 The axial thrust developed in the turbine in N (3) 1.3.5 The power developed by the turbine in MW (3) [20]