Source: Reproduced with permission from Rolls-Royce plc
In this chapter, we address compressors and turbines in an aircraft gas turbine engine. We first present the fundamental equations that are applicable to all types of turbomachinery and then follow with the flow characteristics of each machine in subsequent Chapters 9and 10.
Turbomachinery is at the heart of gas turbine engines. The role of mechanical compression of air in an engine is given to the compressor. The shaft power to drive the compressor typically is produced by expanding gases in the turbine. The machines that exchange energy with a fluid, called the working fluid, through shaft rotation are known as turbomachinery. The machines where the fluid path is predominantly along the axis of the shaft rotation are called axial-flow turbomachinery. In contrast to these machines, in radial-flow turbomachinery the fluid path undergoes a 90° turn from the axial direction. These machines are sometimes referred to as centrifugal machines. A mixed-flow turbomachinery is a hybrid between the axial and the radial-flow machines. In aircraft gas turbine engines, the axial-flow compressors and turbines enjoy the widest application and development (Figure 8.1). The centrifugal compressors and radial-flow turbines are used in small gas turbine engines and automotive turbocharger ...