11 Due 10/17

1. A mixing chamber takes in a stream of R134-a at 1 MPa and 12$\POW9,{\circ}$C and a second stream at 1MPa and 60 $\POW9,{\circ}$C. The first stream has twice the mass flow of the second; $\dot{m}_1=2\dot{m}_2$. No data is given about the stream 3 exiting the mixing chamber. Therefor, you will need to make two approximations typical for mixing chambers. One is that the pressure changes across the chamber are negligible. You are asked to find the exit temperature and the exit quality if it is defined. Construct all phases that are not given in a $Pv$ diagram. Label the lines with their values.

2. An adiabatic turbine receives 12kg/s of steam at 10 MPa and 450$\POW9,{\circ}$C at a velocity of 80 m/s. The steam exits the turbine at a pressure of 10 kPa, with a quality of 92%, at a velocity of 50 m/s. Find the kinetic energy change of the water, the produced power, and the diameter of the entrance pipe.

3. Engine coolant (glycerine) enters the radiator of your car with a temperature of 100$\POW9,{\circ}$C and exits it at 50$\POW9,{\circ}$C. If the coolant must remove 30 kW of heat, what must be its mass flow rate through the radiator? If the heat is carried off by ambient air at about one atmosphere that has a temperature of 15 degrees before flowing through the radiator and 35 degrees after it, what is the volume flow of the air?

4. If high pressure steam is needed for some purpose in a power generation plant, it is often bled off from the high pressure side of the turbine. This is called cogeneration. Assume a well insulated turbine takes in 50 kg/s of steam at 10 MPa and 600$\POW9,{\circ}$C, and that 10 kg/s at 400 kPa and 200$\POW9,{\circ}$C is bled off, while the remaining steam exits at 100 kPa and a quality of 0.8. Construct the phase of the bled-off steam in the $Tv$ diagram and so verify that it is indeed still steam. Find the power the turbine generates, and compare it to the power it would generate if no steam was bled off.