Rotodynamic

Rotodynamic refers to turbomachinery in which energy is transferred between a driving mechanism and a fluid primarily through rotating components. Devices described as rotodynamic either add energy to a fluid, such as pumps and compressors, or extract energy from it, such as turbines, by means of rotating impellers or blades. The term contrasts with positive-displacement equipment, where energy transfer occurs by changing the fluid volume rather than by imparting velocity.

In operation, a rotodynamic pump uses an impeller to accelerate the fluid and convert kinetic energy into pressure as the flow is guided by the housing and diffuser. A turbine extracts energy from a high‑energy fluid to turn a shaft and perform work. A compressor increases the fluid’s pressure by rotating blades that elevate its enthalpy. Typical ro­todynamic machines share components such as a rotor with blades, a casing or diffuser, a shaft, seals, and bearings. Performance is described by head or pressure rise versus flow, efficiency, and specific speed, with characteristic curves used to select equipment for a given duty.

Common rotodynamic devices include centrifugal (radial) pumps and mixed- or axial-flow pumps; rotodynamic turbines cover reaction and impulse types; and fans and compressors are also categorized as rotodynamic. The category encompasses a wide range of equipment used across industries.

Applications include water supply and wastewater systems, power generation, industrial processing, and HVAC. Selection is based on duty requirements, reliability, and performance characteristics depicted by efficiency maps and head–flow curves.