Fall 1999, METBD 330 - Thermodynamics

Prof. Dave Johnson, dhj1@psu.edu, Penn State - Erie, The Behrend College

Unsteady Flow Processes

  A stationary, un-insulated 2m³ rigid tank initially contains air at 100 kPa and 22^oC.  Air is available in an attached supply line at constant values of 600 kPa and 22^oC.  The valve to the supply line is opened and air enters the tank until the tank pressure reaches the supply line pressure.  At that point, the valve is closed and the final temperature in the tank is 77^oC.  Determine the mass of air that entered the tank and the amount of heat transfer.  (Answers: 9.58 kg, -327.5 kJ)  Hint: u = Cv T, h = CpT

  A 0.2m³ rigid tank is equipped with a pressure regulator (so the pressure can be maintained as a constant).  The tank initially contains steam at 2 MPa and 300^oC.  Heat is added to the steam in the tank until the final temperature is 500^oC. During this process, the regulator valve releases steam to maintain the pressure.  Determine the amount of heat transfer.  HINT:  use the average properties of the steam exiting the tank.  (Answer: 604.6 kJ)