TABLE OF CONTENTS This chapter briefly explores how the performance and the behavior of an actual engine are related to the characteristics of its components. Our view is now different from that taken in chapters 2 and 3, where the components were characterized by thermodynamic parameters ?, ?, ? with no reference to the shape or size of the machine. Here we begin with the characteristics of actual components, expressed by performance maps for the compressor (figure 5.33), the turbine (figure 6.17), the inlet (figure 4.22), the fan (figure 5.31), and perhaps other components if necessary. These maps represent the behavior of real devices whose geometry is fully specified. Our task is to determine how they interact when combined into an engine or a propulsion system.
The task is most conveniently divided into two parts. The first (termed component matching) involves applying the constraints that result from the need for the components to work together; the second involves predicting the performance of the resulting assembly.
Suppose that we have a compressor with the map of figure 5.33, and a turbine with the map of figure 6.17, mounted on a single shaft with a combustor between them to form a gas generator, which is the heart of any gas turbine engine. With an inlet and a nozzle, a gas generator becomes a turbojet engine (figure 1.4). With a fan and a fan drive turbine, it becomes a turbofan engine (figure 1.6). With a power...
