A Review On Secondary Fluid Injection In Turbomachines

Abstract

A turbomachine is basically a rotating blade or a set of rotating blades which in some cases utilizes the energy of the working fluid and in other cases imparts energy to it. Turbomachines are mainly divided into three ways i.e. on the basis of velocity vector of incoming flow (Axial, radial and mixed), on the basis of amount of fluid flow (open and closed), on the basis of utilize the energy (power consuming and power producing). There we will discuss on the third part of turbomachines i.e. on the basis of power consuming or power producing. A turbomachine works on either a high energy fluid or low energy fluid which is known as the primary fluid. Through the years many developments have been made to increase the efficiency of the machines to keep pace with the increasing population and the development of new technologies. In many Turbomachines these requirements are met by introduction of a secondary fluid at specific places or parts of the turbomachine. The secondary fluid can be different from the primary fluid or it can be the same also. There are many methods which utilize the properties of the secondary fluid to increase the performance of the turbomachine. Some methods are in widespread use while others are might be used in future. Some of the examples of methods of injecting secondary fluid are: water injection in jet engines to suppress noise and thus decrease the vibroacoustic stresses. Film cooling technique which injects cold air or steam on gas turbine parts to increase their working life which allows higher firing temperatures and thus increases efficiency. In compressors water is used to increase humidity which helps to increase the efficiency of a hydrogen cell. Apart from all these examples there are so many other applications of fluid injection in turbomachines which are like Air in hydro machines, Air in gas turbines, Air in pumps, Air in marine hydrokinetic turbine, Steam injection in gas turbines, Water injection in jet engines.