Abstract
An investigation is conducted on the flow in a moderately wide gap between an inner rotating shaft and an outer coaxial fixed tube, with stationary end-walls, by three-dimensional Reynolds-averaged Navier–Stokes (RANS) computational fluid dynamics (CFD), using the realizable k−ε model. This approach provides three-dimensional spatial distributions of static and dynamic pressures that are not directly measurable in experiment by conventional nonintrusive optics-based techniques. The nonuniform pressure main features on the axial and meridional planes appear to be driven by the radial momentum equilibrium of the flow, which is characterized by axisymmetric Taylor vortices over the Taylor number range 2.35×106≤Ta≤6.47×106. Regularly spaced static and dynamic pressure maxima on the stationary cylinder wall follow the axial stacking of the Taylor vortices and line up with the vortex-induced radial outflow documented in previous work. This new detailed understanding has potential for application to the design of a vertical turbine pump head. Aligning the location where the gauge static pressure (GSP) maximum occurs with the central axis of the delivery pipe could improve the head delivery, the pump mechanical efficiency, the system operation, and control costs.
Highlights
Many scientific and industrial applications feature a flow in the annulus of two concentric rotating shafts
This axisymmetric pattern recurs along the axial cylinder length of the whole Computational Fluid Dynamic (CFD) simulation domain with successive cells of the vortices driving the flow in a similar radial path at their conference points
Whereas many of the previous studies that investigated the Taylor vortex flow concentrated on the analysis of the velocity distributions in the meridional plane, this current study documents qualitative and quantitative predictions of the spatial distribution of static and of dynamic pressure on the meridional and on the axial planes across the entire annulus, which have not been previously reported
Summary
Many scientific and industrial applications feature a flow in the annulus of two concentric rotating shafts. In the case in which the inner shaft is rotating and the outer tube is kept fixed, Taylor vortices [1, 2, 3, 4] can develop in the annulus between the two coaxial shafts, due to an unstable pressure gradient acting on the fluid particles. As the Taylor number increases beyond this range, a small mean axial pressure gradient is superimposed and three-dimensional secondary flows with vortex structures are generated. The modelling and the analysis of these flow patterns provide information about heat and mass transfer rates, pressure distributions, and axial mixing in important industrial applications, such as liquid-liquid extraction [5, 6], exhaust fans, synthesis of silica particles [7], emulsion polymerization [8], bio-reactions [9], as well as heterogeneous catalytic reactions [10]. This research contributes to the global challenge identified by the Research Councils UK (RCUK) of achieving a more sustainable energy use and to the UK government Official Development
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
