Question

1. A rigid (constant volume) tank sealed by a valve initially contains 100 kg of air at a pressure of 100 kPa and 300 K. At time t = 0, the valve for the air tank is opened in a controlled manner and air leaks out isothermally (constant temperature) of the tank at a constant mass flow rate of 1 kg/s. The valve is closed after 75 seconds. Answer the following questions: Assuming air is an ideal gas, what is the volume of the tank in m3? The molar mass for air, MW, is 28.7 kg/kmol and the universal gas constant, R, is 8.314 kJ/kmol-K Calculate the initial specific volume and density for the air inside the tank. Report your answers in m/kg and kg/m'. Using the conservation of mass equation, find: a b. C. The final mass of air inside the tank ii. Draw a graph with time on the x axis and mass on the y axis. Label the initial and final values ii Plot the velocity out of the tank with respect to time if the area of the tank outlet is 0.01 m2 Calculate the final pressure of the air inside the tank after the valve is closed d. Air Tank Valve

Answer 1

mz loo hg A0.01m3 lookPa 300 K n,=IK9/e for 75-8econds Value is opend Air Vale valume at tank Sas ideal gas PU=mRT M 196x 8.31HX103 X 300 t8xpxDO Volu eme af tants 3 86.90592 m mitial pecitic uolume 86.90592 1 1 B 990911

inside He fank mass af ain tiral Ualue is openeol Aratr Sec mass escaped =IX79 ma&s hg Hinal mass in Side tamk 100-S = 25K9. VS mass m as sec t se C V'vst A Orolm 2 PAV C : m AV d.ol Xl-1S066 u990b 9I8 =

oR8766 11 86.957 eof Vi e RA: A : 347. 62 368 o0l Xo.28766 3H62 300 Aat aumund ar Stsec as 95 t fimal pressure V 86.90Sq2 30o (as iso themall procees T V m 8.31 300 p 890593 28.7 25.002 K Pq