. The container in Fig. 4.19 is initially evacuated. Then the valve is opened, and atmospheric air flows in, compressing the spring. The entire inflow and compres- sion process is adiabatic. The temperature of the atmospheric air is 20°C. When the process is over, the volume of the contained air is 10 m³, its pressure is 1 atm, and the work done on the piston and spring system is 13 kJ. The air in the container is perfectly mixed. What is the temperature of the air in the container?

Refrigerant R-134a to the compressor of a refrigeration machine It enters at 140 kPa pressure and -10 °C, and exits at 1 MPa pressure. Volumetric flow of the refrigerant entering the compressor It is 0.23 m³/minute. The refrigerant enters the throttling valve at a pressure of 0.95 MPa and at 30 °C, and exits the evaporator as saturated steam at -18 °C. Adiabatic efficiency of the compressor It is 78%. Show the cycle in the T-s diagram. And; a) Calculate the power required to run the compressor. b) Calculate the heat absorbed per unit time from the cooled medium.            ( COPSM=? ) c) Calculate, between the evaporator and the compressor, how much the pressure of the refrigerant drops and how much the heat gain.

Helium is compressed through a compressor steadily.  At the inlet the pressure is   and the temperature is  . At the exit the pressure is    and the temperature is  .  The power input is   and the heat loss rate is   during this process.  Neglect the kinetic and potential energy changes.  Assume helium is ideal gas with a constant specific heat   and its specific heat ratio  , which means that enthalpy can be calculated using  .  Calculate the work per unit mass   _________

Steam at a rate of 200 kg/min enters a turbine at 350°C and 40 bar through a 7.5-cm internal diameter pipe. The turbine operation is adiabatic, and the effluent leaves as saturated water at 5 bar through a 5-cm diameter pipe. 1. Calculate the work produced by the turbine in kW. 2. What is the enthalpyand phase of the effluent stream? 21 If it leaves the turbine at 75C and 5 bar 22 If it leaves the turbine at 30C and 5 bar 7.5

No Handwriting please

An insulated tank A of 0.6 m3 volume is connected to an insulated tank B of 0.3m3 volume. Initially, tank A contains steam at 0.2 MPa and 200 °C, and tank B contains wet steam at 0.5 MPa and 85% quality. The valve is opened and flow occurs until equilibrium (both mechanical and thermal) is attained. Estimate the final pressure.

A rigid tank of volume 10 m³ initially contains saturated water vapor at a temperature of 120 °C. Steam at a pressure 1.2 MPa and a temperature of 400 °C enters the tank through a valve in steam line that is connected to the tank until the final pressure in the tank is 800 kPa, at which time the temperature is 200 °C. All kinetic and potential energy effects can be neglected. A schematic of the problem and properties at all state points except state 1 are shown in the figure below. All of the properties at state 2 and the inlet state i are provided on the figure. Initial State in Tank T₁-120 °C, Sat. vapor u₁=? kJ/kg V₁=? m³/kg Pi=1.2 MPa, Ti-400 °C hi-3261.3 kJ/kg V=10 m³ Final State in Tank T: 200 °C, P₂-800 kPa u₂= 2631.1 kJ/kg v₂=0.26088 m³/kg Qout For Question 6: The initial specific internal energy, u1, of the saturated vapor in the tank in kJ/kg is