A 4 m3 storage tank containing 2 m3 of liquid is about to be pressurized with air from a large, high-pressure reservoir through a valve at the top of the tank to permit rapid ejection of the liquid (see figure). The air in the reservoir is maintained at 100 bar and 300K.
The gas space above the liquid contains initially air at 1 bar and 280 K. When the pressure in the tank reaches 5 bar, the liquid transfer valve is opened and the liquid is ejected at the rate of 0.2 m3/min while the tank pressure is maintained at 5 bar.
What is the air temperature when the pressure reaches 5 bar and when the liquid has been drained completely? Neglect heat interactions at the gas-liquid and gas-tank boundaries. It may be assumed that the gas above the liquid is well mixed and that air is an ideal gas with a constant =30 J/mole K.