Turbine Engine Cycle Design

The task was to derive a set of equations for a turbine engine that described the thermodynamic changes across each stage or component in the engine, and also engine performance parameters such as specific thrust and efficiency. Then it was necessary to develop a computer program that could model the engine cycle analysis for several different cases. In other words, a model that could model engines that included variations of combinations of the components analyzed.

After the set of equations was derived it was necessary to design four different cases of engines and find the maximum thrust of each of the engine cycles. The first a commercial airliner in ground roll and high altitude subsonic cruise, and a long range missile at low altitude subsonic cruise and high altitude supersonic cruise. Then it was necessary to pick or design a new engine cycle that satisfied both conditions required for each aircraft.

In order to develop the set of equations, the first step was to analyze each individual component of the engine, for an engine that contained every component. That way the results could be generalized to equations with less components, without loss of continuity. The following is the process used to derive the equations.

Then Mathematica was used to be able to perform quick analysis of different engines. With given inputs, a program was written that worked through each component determining thermodynamic changes utilizing the set of equations that was derived.

Once the equations were derived, an iterative technique was used to find the values of bleed, bypass, and fuel air ratios for the main burner and afterburners. The process to derive these equations and the resultant equations are presented below.

Once these were obtained, the maximum thrust was for the four specific cases was derived and are summarized in the table below. Overall this was a great project to learn about engine design and applications of thermodynamic concepts. It is something that I plan on exploring in the future, designing more complex (and sometimes theroetical) engines.