City Research Online

Abstract

Viscoelastic fluids are promising candidates for the thermal management of high heat-flux components of electrified powertrains, such as the battery pack via immersion cooling concepts. This study investigates the ability of viscoelasticity-inducing additives to manipulate flow patterns and enhance heat transfer in a benchmark bluff body geometry, under inertial laminar flows using dilute polymer solutions. Simulations were conducted in OpenFOAM to model viscoelastic fluid flow using the Phan-Thien-Tanner (PTT) constitutive equation and were validated against particle image velocimetry (PIV) experimental data. Two benchmark-flow configurations were studied: (i) a 180-degree channel bend and (ii) flow around a heated bluff body. Results show that viscoelastic fluids enhance vorticity in both geometries to varying extents compared to Newtonian fluids, as a function of the PTT-model slip (ζ) parameter. Heat transfer studies with a heated bluff body showed a trend of increasing heat flux for the viscoelastic fluid, with a measurable 3% enhancement at a Reynolds number of 800 also captured by the numerical results. The study highlights the potential of leveraging the influence of second normal stress difference in viscoelastic fluids for thermal management and discusses avenues for further optimisation.

Publication Type:	Conference or Workshop Item (Paper)
Publisher Keywords:	Heat transfer enhancement, wall-bounded flows, relaxation time, bluff body
Subjects:	T Technology > TC Hydraulic engineering. Ocean engineering T Technology > TJ Mechanical engineering and machinery
Departments:	School of Science & Technology School of Science & Technology > Department of Engineering
SWORD Depositor:	Symplectic Administrator

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