Introduction

Turbomachines are devices that feature the continuous flow of a fluid through one or more rotating blade rows. Energy, as work, is extracted from or transferred to the fluid by the dynamic action of the blade rows. If energy is extracted from the fluid by expanding it to a lower pressure, the devices are called turbines (steam, gas, or hydraulic). If energy is transferred to the fluid, thereby increasing its pressure, the devices are termed pumps, compressors, or fans. Stationary vanes guide the flow of fluid before and/ or after the rotating blade rows.