Heat transfer enhancement in a cross-slot micro-geometry

Abed, Waleed M, Domingues, Allysson F ORCID: 0000-0003-2071-6738, Poole, Robert J ORCID: 0000-0001-6686-4301 and Dennis, David JC ORCID: 0000-0003-0214-7885 (2017) Heat transfer enhancement in a cross-slot micro-geometry. INTERNATIONAL JOURNAL OF THERMAL SCIENCES, 121. pp. 249-265. ISSN 1290-0729, 1778-4166

Access the full-text of this item by clicking on the Open Access link.

Official URL: https://doi.org/10.1016/j.ijthermalsci.2017.07.017

Abstract

The cross-slot is a common geometric shape in microfluidic applications. In this article we investigate the influence of a purely-inertial flow instability on the enhancement of heat transfer in a cross-slot micro-geometry where symmetry is broken but the flow remains steady. The cross-slot comprises two crossed square channels with opposed inlets and outlets, which generate a stagnation point at the geometric centre (when the flow remains stable and symmetric). In the experiments, Rhodamine-B is utilised as a temperature-sensitive dye to measure the temperature distribution, these results compare well with three-dimensional numerical simulations, which are used to further elucidate the flow behaviour and heat transfer characteristics. The flow of a Newtonian fluid is steady, two-dimensional and produces a sharp symmetric boundary between fluid streams entering the cross-slot from opposite directions at low Reynolds numbers (Re). Therefore, only conduction heat transfer occurs between the fluid streams as there is virtually no mixing between them. Beyond a certain critical value of Re, approximately 40, a steady symmetry-breaking bifurcation occurs and convective heat transfer arises because an axially oriented spiral vortex is created in the outlet arms. The effects of this purely-inertial instability suggest it is an effective method of enhancing mixing and heat transfer in microfluidic devices that can be exploited in applications such as lab-on-chip and micro chemical-reaction devices at relatively low Reynolds numbers (i.e. Re < 100).

Item Type:	Article
Uncontrolled Keywords:	Cross-slot, Micro-geometry, Heat transfer, Steady symmetry-breaking bifurcation, Spiral vortex, Hysteresis
Depositing User:	Symplectic Admin
Date Deposited:	20 Jul 2017 10:54
Last Modified:	06 Dec 2024 22:39
DOI:	10.1016/j.ijthermalsci.2017.07.017
Open Access URL:	http://www.sciencedirect.com/science/article/pii/S...
Related URLs:	Author Publisher
URI:	https://livrepository.liverpool.ac.uk/id/eprint/3008546