A 30 m3 steam boiler contains a mixture of liquid water and water vapor at 700 kPa. Initially the vapor and liquid occupy equal volumes. A valve is opened to withdraw the vapor and simultaneously another valve is opened to add liquid water. Through some time interval, 15,000 kg of 40°C liquid are added to the boiler, while the vapor is being withdrawn. Through this whole process the pressure inside the boiler is maintained at 700 kPa. At the end of the process the liquid water remaining in the tank occupies ¼ of the boiler volume, with vapor filling the rest. Kinetic and potential energy impacts are negligible in this process.
1. What is the temperature in the boiler before the valves are opened?
2. How much vapor is withdrawn through the whole process (in kg)?
3. Fill in the values in the schematic below.
4. How much heat was transferred to the boiler through this process?