The invention of internal combustion engines in the early 19th century led to the discovery of the use of the cheap energy that is oil and this allowed the world to develop and progress in the modern world Today. Humans have been able to perform multiple jobs with little manual labor, using internal combustion engines powered by fossil fuels. Internal combustion engines are mechanical power devices that convert thermal energy into mechanical energy with the combustion process occurring at the system boundary (Rolle, 2005). Internal combustion engines invented in the 19th century include the Otto engine, the diesel engine, and the gas turbine engine. The gas turbine engine is one of the most popular engines today due to its high torque-to-weight ratio compared to other types of internal combustion engines. As explained by Cengel and Boles (2011), the gas turbine engine operates in a 6-step process, namely air intake, compression, fuel injection, combustion, expansion and exhaust (refer to Figure 1 in 'Appendix 1). First, the gas turbine engine operation begins with the air intake process. Like all internal combustion engines, oxygen is needed to support fuel combustion, and the source of oxygen comes from fresh intake air. Initially, the fan is rotated by a crankshaft driven by the engine's turbine. motor. The rotating fan then creates a vacuum or vacuum on the intake side. Next, the surrounding air is drawn towards the inlet and flows into the inlet of the gas turbine engine (Cengel & Boles, 2011). At the same time, the pressure on the other side of the fan increases as it is compressed with a lower pressure ratio and causes the air in the outlet side of the fan to move out... to the center of the paper... .. ..operation.Works Cited Cengel, Y.A., & Boles, M.A. (2011). Thermodynamics: An Engineering Approach (7th ed.). New York, NY: McGraw-Hill.¬¬¬¬Ganesan, V. (1999). Gas turbines. New Delhi, India: Tata McGraw-Hill. Rolle, K. C. (2005). Thermodynamics and thermal power (6th ed.). Upper Saddle River, NJ: Prentice Hall. Saravanamutto, H.I.H., Rogers, G.F.C., Cohen, H., & Straznicky, P.V. (2009). Gas Turbine Theory (6th ed.). London, UK: Prentice Hall. Sirignano, W. A., & Liu, F. (1999). Increased gas turbine engine performance through combustion within the turbine. Journal of Propulsion and Power, 15(1), 111-118. Walsh, P. P., & Fletcher, P. (2004). Gas Turbine Performance (2nd ed.). Oxford, UK: Blackwell. Wilson, D. G., & Korakianitis, T. (1998). The design of high-efficiency turbomachinery and gas turbines (2nd ed.). Upper Saddle River, NJ: Prentice Hall.