Practice Final Exam

• A large rocket engine delivers hydrogen at 1500°C and 3 MPa to a nozzle with an exit pressure equal to the ambient pressure of 54 kPa. If the thrust of the rocket is 2 MN what is the exit velocity and mass flow rate of hydrogen? (use k = 1.41 and R = 4124 J/kgK)

• Air, with a stagnation condition of 450 K and 250 kPa flows through a nozzle. At the location where the cross-sectional area equals 15 cm2 there is a normal shock. If the mass flow rate is 0.4 kg/s estimate the Mach number and the stagnation pressure after the shock.

• A 5-mm capillary tube is used as a viscometer. When the flow rate is 0.71 m3/hr, the measured pressure drop is 375 kPa/m. Estimate the viscosity of the fluid? Is the flow laminar? Can you estimate the density?

• Hydrogen at 20 °C and 1 atm needs to be pumped through an 85 m duct with an aspect ratio of 5:1. The flow rate is 0.7 m3/s and the pressure drop cannot exceed 80 Pa. What should the height and width of the duct be?