This lecture is was created for use in Thermodynamics for Mechanical Engineers at the Rochester Institute of Technology.
This lecture gives an introduction to Turbojet Engines. Turbojets are somewhat unique in the heat engines we’re covering in this class because the energy benefit here is to maximize thrust power from the engine by maximizing the kinetic energy at the exit of the jet. This is different than Ranking Cycles, ICEs, and Brayton cycles that were trying to maximize the Net Power produced for a given heat rate. We learn that the Turbojet Engine has a Brayton Cycle at its heart, but we use a Diffusor and a Nozzle at the inlet and outlet to convert kinetic energy to specific enthalpy and vice versa. I also go through a first law analysis on all of the components to show what equations we can expect when solving these systems. Because kinetic energy is important in this cycle, it’s more important than usual that we be aware of our units as we work through the problem. We finish the lecture by seeing how afterburners are used in military aircraft to provide a further boost to the kinetic energy at the outlet of the jet.
15 окт 2024
