An adiabatic air supply system as shown in Fig. 2 is to be designed by a student. The air flows out from nearly stagnant conditions in the reservoir through a short converging duct into a constant area pipe that discharges the air in the atmosphere. The system should be capable of delivering steady flow of air at Mach number at 0.9 provided the pressure in the reservoir is maintained constant. If the circular pipe diameter is
fixed at 0.04 m, determine the reservoir pressure and atmospheric pressure ratio and the mass flow rate from the system for a range of values of L / D. Take L / D = 100-350 in steps of 50. (assume f = 0.005, p = 100 kPa). Take isentropic flow from the reservoir to the pipe inlet. Present the data generated in a suitable graphical format.
Using the data generated estimate the size of the reservoir that is sufficient to ensure a maximum reservoir
pressure drop rate of (1% of reservoir pressure) per minute for an operating reservoir Temperature of 30 degree Celsius.