Numerical analysis of convective heat transfer enhancement in swirl tubes
- 14 June 2011
- journal article
- Published by Emerald in International Journal of Numerical Methods for Heat & Fluid Flow
- Vol. 21 (5), 559-571
- https://doi.org/10.1108/09615531111135828
Abstract
Purpose: The aim of this paper is to investigate the convective heat transfer in swirl tubes, which are obtained by roto‐translating a circular section eccentric with respect to the rotation axis. The geometry is numerically investigated with the aim of evaluating the convective heat transfer enhancement effect due to the secondary flow induced by the centrifugal force.Design/methodology/approach: The governing equations, i.e. continuity, momentum and energy equations, are integrated numerically within Comsol Multiphysics® environment, under the assumption of incompressible Newtonian and constant properties fluid and of periodically fully developed laminar flow for what concerns both the hydrodynamic and the thermal problem under the uniform wall heat flux thermal boundary condition.Findings: The heat transfer performance of the geometry is discussed in relation to the flow pattern. In particular, the numerical results show that two different stable flow regimes may exist, according to the ratio of the Reynolds number to the dimensionless helix pitch. The Nusselt number augmentation becomes significant for high Prandtl number fluids when a critical Re/P* value, corresponding to the onset of the centrifugal forces induced secondary flow, is reached.Originality/value: The geometry here investigated represents an interesting solution to enhance the convective heat transfer in situations in which the flow, although disturbed, persists in the laminar regime. This type of enhanced tubes shows then interesting heat transfer performances (which becomes particularly significant for high Prandtl number values) by thus suggesting convenient applications also for highly viscous fluids which are often treated under the laminar flow regime.Keywords
This publication has 10 references indexed in Scilit:
- Numerical prediction of turbulent flow and heat transfer in helically coiled pipesInternational Journal of Thermal Sciences, 2010
- A review of flow and heat transfer characteristics in curved tubesRenewable and Sustainable Energy Reviews, 2004
- On heat transfer enhancement in swirl pipe flowsInternational Journal of Heat and Mass Transfer, 2004
- Experimental investigation on heat transfer and frictional characteristics of spirally corrugated tubes in turbulent flow at different Prandtl numbersInternational Journal of Heat and Mass Transfer, 2003
- Convective heat transfer to temperature dependent property fluids in the entry region of corrugated tubesInternational Journal of Heat and Mass Transfer, 2002
- Laminar convection of non-Newtonian fluids in the thermal entrance region of coiled circular tubesChemical Engineering Journal, 2001
- Pressure drop, heat transfer and performance of single-phase turbulent flow in spirally corrugated tubesExperimental Thermal and Fluid Science, 2001
- Laminar forced convection in a helicoidal pipe with finite pitchInternational Journal of Heat and Mass Transfer, 1995
- Flow in Curved PipesAnnual Review of Fluid Mechanics, 1983
- Laminar convective heat transfer in helical coiled tubesInternational Journal of Heat and Mass Transfer, 1978