Wright State University Summer 2014

Department of Mechanical and Materials Engineering

ME 3310: THERMODYNAMICS I, MIDTERM TEST 1

OPEN BOOK, CLOSED NOTES, SHOW ALL WORK

Problem 1: (20 points) The 100-lbm piston is free to move in the vertical cylinder and has a diameter of 5 in. If

the atmospheric pressure is equal to 14.7 psia and the acceleration due to gravity is 32.2 ft/s2, determine the

absolute pressure of the H2O.

Problem 2: (30 points) Nitrogen is contained in a bottle. The nitrogen is at a pressure of 42 atm and a

temperature of −143°C. The bottle has a volume of 0.02 m3. Can the nitrogen be treated as an ideal gas? What is

the mass of the nitrogen in the bottle?

Problem 3: (25 points) A tank whose volume is unknown is divided into two parts by a partition. One side of

the tank contains 0.01 m3 of H2O that is a saturated liquid at 0.8 MPa, while the other side is evacuated. The

partition is now removed, and the working fluid fills the entire tank. If the final state of the working fluid is

200°C and 400 kPa, determine the volume of the tank.

Problem 4: (25 points) Saturated water undergoes process 1-2-3-4, as shown in the figure. The initial pressure

is 0.2 MPa and the final pressure is 0.5 MPa. If the quality at point 2 is 30 percent, find the work done per unit

mass during the entire process.

H2O

V = 0.01 m3

P = 0.8 MPa

Evacuated