Question

Question 2 (30 marks) (a) A fluid flowing into a nozzle with specific enthalpy of 2980 kJ/kg and the velocity is 80 m/s. At the exit of the nozzle, the specific enthalpy of the fluid drops to 2670 kJ/kg. The nozzle orientation is horizontal and the heat loss is negligible. Given that the nozzle inlet area is 0.25 m2 and the specific volume of the fluid is 0.2 m2/kg, calculate the velocity of the fluid at exit, the mass flow rate and the exit area of the nozzle. (13 marks) (b) A horizontal venturi tube, pipe diameter of 500 mm and throat diameter of 250 mm, has a discharge coefficient of 0.95. A differential U-tube manometer, using mercury as the fluid, is connected between pressure tappings at the entrance and at the throat. The venturi tube is used to measure the flow of air. Calculate the actual mass flow rate of air when the difference in the mercury levels in the U-tube is 15 mm. Take densities of air and mercury as 1.2 kg/m3 and 13,600 kg/mº respectively. (17 marks)

Answer 1

No friction loss is taken in nozzle case.