Buoyancy-Induced Flow and Heat Transfer Inside Compressor Rotors

Lead Research Organisation: University of Surrey
Department Name: Mechanical Engineering Sciences


Abstracts are not currently available in GtR for all funded research. This is normally because the abstract was not required at the time of proposal submission, but may be because it included sensitive information such as personal details.


10 25 50
Description Early computational fluid dynamics studies clarified the development of flow instabilities and flow characteristics in a sealed rotating annulus heated on the outer shroud and cooled on the inner cylinder. Further analysis using an incompressible solver with the Boussinesq approximation gave insight into the surface heat transfer within the sealed cavity. The phenomenon of "Ekman layer scrubbing" was identified showing the disc boundary layers to be highly unsteady Ekman layers. The effect of imposing a central axial throughflow in the cavity was also investigated. Although this has important effects, the flow and heat transfer in the outer part of the cavity remains similar to that in the sealed case.

A second phase of the research used a fully compressible flow solver and compared fully-resolved large eddy simulations with those from the incompressible solver and experimental results. A surprising finding was that the Ekman layer scrubbing gave rise to significant frictional heating in the disc boundary layers. With this and other factors now understood, many discrepancies and questions raised by previous published work in the area can be explained. A result of practical interest to gas turbine designers is that the shroud heat transfer agrees with correlations obtained from free convection under gravity.

In the final phase of the research wall modelled large eddy simulation (WMLES) was introduced into the compressible flow solver, comparisons were made with meaTsurements obtained at the University of Bath, and the WMLES was used to study low Rossby number conditions and flow interactions in a dual cavity configuration. The model proved viabl at the most extreme experimental conditions with potential for application to engine conditions. Comparisons with measurements from the University of Bath gave very encouraging levels of agreement. Difficulties were encountered and overcome in modelling low cooling flow rates where an issue with reversed flow in the central axial flow was identified (and is also believed to occur in the experiment). Some experiments at Bath were delayed due to COVID restrictions, and completion of the CFD studies was achieved in 2021, using a funding extension to mitigate the effects of COVID-19.
Exploitation Route During the project regular reviews with the academic and industrial partners took place. The papers published are also attracting considerable interest. The latest paper (to be presented at the 2021 ASME Turbo Expo 2021 and a corresponding journal paper published in 2022) is of particular interest to industry as it gives a clear account of the flow and heat transfer mechanisms (correcting some assumption made in other workers' publications) at research rig conditions with indications of how to extrapolate results to engine conditions.

Exploitation of the research findings has progressed through application of WMLES to a Rolls-Royce Trent engine geometry with funding from an Impact Acceleration Account. The understanding of the flow mechanisms developed and the WMLES technique has been used in consideration of elemental models that can be applied in industry,

Further collaboration with Rolls-Royce and the University of Bath is under discussion.
Sectors Aerospace, Defence and Marine,Energy

Description The results of the research project and the associated Impact Acceleration Account study are being used at Rolls-Royce in defining correlations and assumptions in aero-engine thermal modelling, and are informing interpretation of data and further research at the Universities of Surrey and Bath. Direct industrial impact was achieved through collaboration of staff at the University of Surrey and Engineers at Rolls-Royce. Some of the results are reported in a joint Surrey/Rolls-Royce paper. Material from the research has also been included in a "Tutorial of Basics" on Rotating Disc Flows delivered at the 2022 ASME Turbo Expo in Rotterdam, and in invited lectures to industry responsible for land based gas turbine design and manufacture.
First Year Of Impact 2018
Sector Aerospace, Defence and Marine,Energy
Impact Types Economic

Description EPSRC Impact Acceleration Account - Surrey
Amount £31,557 (GBP)
Organisation University of Surrey 
Sector Academic/University
Country United Kingdom
Start 07/2020 
End 03/2021
Description UKRI COVID-19 Grant Extension Allocation (CoA)
Amount £85,259 (GBP)
Funding ID UKRI CoA RN0450: UKRI COVID-19 Grant Extension Allocation (CoA) 
Organisation University of Surrey 
Sector Academic/University
Country United Kingdom
Start 01/2021 
End 09/2021