ABSTRACT
“Module matching” means the successful interplay of engine geometry and engine parameters. This relates not only to matching between a turbine and the driven compressor, but also to the global synchronization of the different modules, including the diffuser, combustion chamber, nozzle and fan (for turbofan engines), afterburner (for afterburning engines), propeller (for turboprop engines), and load (for gas turbines and turboshaft engines). A turbine is coupled to either a compressor or a fan, thus forming an engine spool, as described in Chapters 4 through 8. However, the performance matching between these two modules is influenced by their front and back modules. A choked nozzle influences the performance of its preceding elements. The diffuser on the contrary controls the mass flow and total pressure/temperature of all the succeeding modules. If the diffuser incorporates a water injection system, the mass flow in the succeeding elements is affected. Fuel addition and pressure drop in the combustion chamber influence the performance of the succeeding turbine and nozzle. The afterburner influences the mass flow rate and inlet pressure to the succeeding nozzle.
