MEN 211 Final, Spring 2006

Notre Dame University Faculty ol Engineering Duca CULL, ep. \ f Final Exam — MEN211 (Thermodynamics I) Spring 2006 - June 20, 2006 1. Acetylene (CzH2) gas at 25°C is bummed with 140% theoretical air, which enters the bumer at 25°C, 100 kPa, 80% relative humidity. The combustion products form a mixture of COz, H20, No, O2, and NO in chemical equilibrium at 2200 K, 100 kPa. This mixture is then cooled to 1000 K very rapidly, so that the composition does not change. Determine the mole fraction of NO in the products and the heat transfer for the overall process. 2. A saturated air-water vapor mixture at 20°C, 100 kPa, is contained in 50-m° closed tank in equilibrium with 1 kg of liquid water. The tank is heated to 80°C. Is there any liquid water in the final state? Find the heat transfer for the process. 3. A small power plant with reheat produces steam at 3 MPa, 600°C in the boiler. It keeps the condenser at 45°C by transfer of 10 MW out as heat transfer. The first turbine section expands to 500 kPa and then flow is reheated followed by the expansion in the low-pressure turbine. Find the reheat temperature so the turbine output is saturated vapor. For this reheat find the total turbine power output and the boiler heat transfer. Sey . Points: 1 (35%), 2 (30%), and 3 (35%).