Simplified Representation of the Gas Turbine Cycle

Figure 10.9a depicts a standard schematic diagram representing a simple straight – through turbojet engine, as shown in Figure 10.4, with appropriate station numbers. The thermodynamic cycle associated with gas turbines is known as the Joule cycle (also known as the Brayton cycle). Figure 10.9b is the corresponding temperature- entropy diagram of an ideal Joule cycle in which compression and expansion take place isentropically.

Real engine processes are not isentropic and losses are involved associated with increased entropy. Figure 10.10 is a comparison of real and ideal cycles.

10.1 Formulation and Theory: Isentropic Case

Gas turbine equations relevant to this book are provided in this section and are valid for all types of processes. For more details, see [2] through [6].