Hi there. I have a problem solving this task: Insulated tank of volume 5 m3 and with a valve was filled with perfect di-atomic (κ = 1.4) gas at pressure 4 bar.
Initially the valve was closed. A 12 kW electric heater was installed inside the tank. The heater was turn on and at the
same time the exit valve was opened. The gas which is leaving the tank through the valve has constant temperature.
Calculate the time needed to decrease the pressure in the tank to 2 bar. The gas is not known (it's not air, only k=1.4 is known)
Hey, welcome to the forum!
I think there is some information missing in this problem.
1. This is an unsteady process.
2. To apply energy balance there is a need to calculate mass that is exiting out of the control volume which is nothing but the difference between initial and final mass inside the control volume.
3. To use Pv =mRT relation one must know the gas constant value and initial temperature.