Power Sensitivity Modeling and Analysis in Gas Turbine Engine Compressor Design

by Connie Estep. This is an abstract of Connie's second-place award-winning entry in the International Student Technical Communication Competition (ISTCC).

The rising costs of fuel and the effects of global warming have dictated the need for more efficient engines. The compressor in a jet engine takes in a mass of air through the inlet, compresses it, and sends it to the combustor, where it is ignited. The large amount of power needed for the compressor to operate decreases the total engine's output power, thus decreasing engine thrust.

With the goal of finding an alterable variable for increasing engine efficiency by decreasing the power needed for compressor operation, I developed a model using Matlab/Simulink to input six parameters and calculate five unknowns that were dependent on the input variables. Simulink graphically models and simulates systems in conjunction with Matlab, allowing the user to integrate handwritten code with the Simulink library functions. The input values for the mass flow rate and the pressure ratio were altered in both the positive and negative directions by up to 10 percent. The overall pressure ratio of the compressor quantifies how much it compresses the air passing through it, and can be changed by adding or subtracting stages from the compressor. Similarly, mass flow rate can be changed by varying the size of the inlet in the engine.

An increase in the pressure ratio caused an increase in both temperature ratio and power needed to operate the compressor, decreasing efficiency. Although the mass flow rate also increased the required power, the effect was not as pronounced. Optimization in compressor design allows for efficient operation of a gas turbine engine, fuel conservation, and protection of the atmosphere.