ESDU Engineer

FLOW IN ROTATING COMPONENTS - DISCS, CYLINDERS AND CAVITIES

ESDU 07004 introduces the subject of flow in applications where rotating machinery components induce flow rotation. There are many examples of rotating and swirling flow in engineering such as the flow between a stationary disc and a rotating disc, in a gas turbine engine or turbocharger, and the flow in an annulus with a rotating inner cylinder, between the armature and stator of an electric motor. In ESDU 07004, the phenomena involved in rotating flows are introduced and guidance on the techniques for modelling specific rotating flow applications involving discs, cylinders and cavities is provided. Emphasis within ESDU 07004 has been placed on presenting correlations based on analytical, experimental and the computational fluid dynamics (CFD) models for parameters such as mass flow, boundary layer thickness, swirl speed, pressure distribution and moment used in parametric design studies and optimisation.

ESDU 07004 includes the analysis of laminar, transitional and turbulent flow for the case of a disc rotating in a fluid. This case is used as the basis for extension to more complex rotating disc applications such as those involving a disc rotating adjacent to a stationary disc with a shroud and superposed supply of fluid, i.e. rotor-stator wheelspace systems. The cases of a rotating cylinder in a fluid and of an annulus where one or both of the cylinders are rotating are also considered. A common configuration for rotating cavities where two adjacent discs are co-rotating is introduced.

Typical configurations considered are illustrated in the table below which is extracted from Tables 3.1, 3.2 and 3.3 of ESDU 07004. The principal relationships relevant to a particular geometric configuration can be rapidly identified in these tables. Details of the development and limitations of validity for the relationships presented are given in the relevant sections of ESDU 07004.

Queries regarding this article should be directed to Dr Francesca Iudicello, Head of the Fluid Mechanics Group: francesca.iudicello@ihs.com