Chapter 6 - Three-dimensional Flows in Axial Turbomachines

Abstract

Publisher Summary This chapter focuses on the three-dimensional flow in axial turbomachinery. An analysis called the “radial equilibrium method,” widely used for three-dimensional design calculations in axial compressors and turbines, is based upon the assumption that any radial flow occurring is completed within a blade row. The radial equilibrium equation applies to compressible flow as well as incompressible flow. With constant stagnation enthalpy and constant entropy, a free-vortex flow, therefore, implies uniform axial velocity downstream of a blade row, regardless of any density changes incurred in passing through the blade row. The design problem (the tangential velocity distribution) with the axial velocity variation and the direct problem (the swirl angle distribution), with the axial and tangential velocities being determined, are specified in the chapter. It also includes an introduction to the subject of computational fluid dynamics that plays a large part in turbomachinery design and analysis. All the principles detailed in this chapter are equally applicable to the numerical and experimental studies of turbomachines. Radial turbomachinery remains hugely important for a vast number of applications such as turbo charging for internal combustion engines, oil and gas transportation, and air liquefaction. As jet engine cores become more compact, there is also the possibility of radial machines finding new uses within aerospace applications.