A steel tank contains 14 lbm of propane (liquid + vapor) at 70 F with a volume of 0.25 ft3. The tank is now slowly heated. Will the liquid level inside eventually rise to the top or drop to the bottom of the tank? What if the initial mass is 2 lbm instead of 14 lbm?
Constant volume and mass
v2 = v1 = V/m = 0.25/14 = 0.01786 ft3/lbm
vc = 3.2/44.097 = 0.07256 ft3/lbm
v2 < vc so eventually sat. liquid ⇒ level rises
If v2 = v1 = 0.25/2 = 0.125 > vc
Now sat. vap. is reached so level drops
