THE UNIVERSITY OF MICHIGAN
Department of Mechanical Engineering
ME 235 Thermodynamics I / Winter 2014 / Section 002
Due date: Mar. 13 2014
4.83 The main waterline into a tall building has a pressure of 600 kPa at 5 m below ground level. A
pump brings the pressure up so the water can be delivered at 200 kPa at the top floor 100 m above ground
level. Assume a flow rate of 10 kg/s liquid water at 10°C and neglect any difference in kinetic energy and
internal energy u. Find the pump work.
4.87 A steam turbine receives steam from two boilers. One flow is 5 kg/s at 3 MPa, 700°C and the other
flow is 10 kg/s at 800 kPa, 500°C. The exit state is 10 kPa, with a quality of 96%. Find the total power out
of the adiabatic turbine.
4.88 A compressor receives 0.1 kg/s R-134a at 150 kPa, -10°C and delivers it at 1000 kPa, 40°C. The
power input is measured to be 3 kW. The compressor has heat transfer to air at 100 kPa coming in at
20°C and leaving at 30°C. How much is the mass flow rate of air?
4.102 A copper wire has been heat treated to 1000 K and is now pulled into a cooling chamber that has
1.5 kg/s air coming in at 20°C; the air leaves the other end at 60°C. If the wire moves 0.25 kg/s copper,
how hot is the copper as it comes out? 4.124 A modern jet engine has a temperature after combustion of about 1500 K at 3200 kPa as it enters
the turbine section (see state 3, Fig. P.4.124). The compres