Temperature Rise in Electroosmotic Flow of Typical Non-Newtonian Biofluids Through Rectangular Microchannels

Abstract

Electroosmosis is the main mechanism for flow generation in lab-on-a-chip (LOC) devices. The temperature rise due to the Joule heating phenomenon, associated with the electroosmosis, may be detrimental for samples being considered in LOCs. Hence, a complete understanding of the heat transfer physics associated with the electroosmotic flow is of high importance in design and active control of LOCs. The objective of the present study is to estimate the temperature rise and the thermal entry length in electroosmotic flow through rectangular microchannels, having potential applications in LOC devices. Along this line, the power-law rheological model is used to account for non-Newtonian behavior of the common biofluids encountered in these devices. A mixed type of thermal boundary condition is employed at the channel surface, instead of routinely presumed constant wall heat flux or constant wall temperature conditions. A finite difference-based numerical method is employed for solving the governing equations in dimensionless form. An approximate solution, based on the premise of a uniform temperature field throughout the channel cross section, is also obtained for the bulk mean temperature, which is found to be of high accuracy. This, accompanied by the assessments of the temperature profile, reveals that the temperature variations in the channel cross section are negligible, and as a result, the bulk mean temperature can be used as a very precise estimate of the maximum temperature in an LOC device. Moreover, the evaluation of the entry length shows that a thermally fully developed flow is hardly achieved in practical applications because of small length scales involved. Accordingly, the maximum temperature rise may significantly be smaller than what is calculated based on a thermally fully developed flow assumption.

Study of Heat and Mass Transfer in Electroosmotic Flow of Third Order Fluid through Peristaltic Microchannels

“…Here m e is the electroosmotic parameter. The analytical solution of above Equation (14) subject to boundary conditions ∂Φ ∂y = 0, at y = 0 and Φ = 1, at y = h(x) is obtained as;…”

“…Hadigol et al [13] considered the microscopic mixing characteristics of the power-law fluid in electroosmosis. Yavari et al [14] demonstrated an increase in EOF temperature of bio-fluids (non-Newtonian) via microchannel. Furthermore, Bandopadhyay et al [15] studied electroosmosis and peristalsis in microchannels.…”

Analysis of pulsatile combined electroosmotic and shear-driven flow of generalized Maxwell fluids in a microchannel with slip-dependent zeta potential

“…This led to the exploitation of the electroosmotic flow actuation method, where an electric field is applied to transport an electrolyte solution through narrow channels in the presence of an electrical double layer (EDL) across the electrolyte-substrate interface. Extensive studies on the hydrodynamic behavior of electroosmotic flows have been reported using biofluids [1][2][3][4], polymeric solutions [5,6] and colloidal suspensions [7][8][9]. Liu et al [3] modelled a way to pump non-conducting fluids and biofluids which couldn't be put directly in an electric field.…”

Heat Transfer Characteristics of an Electroosmotic Flow of Viscoelastic Fluid in Slit Microchannel

“…Most commonly, the biofluids that are used for analysis and detection schemes are blood or DNA solutions, which shows viscoelastic behavior and have different flow characteristics than that of Newtonian fluids (Park and Lee [2008a,b]). In addition to this, particular interest was also shown towards the thermal characteristics of electroosmotic flow of non-Newtonian fluids (Sadeghi et al [2010(Sadeghi et al [ , 2011, Escandon et al [2011Escandon et al [ , 2013, Sanchez et al [2013], Yavari et al [2013], Goswami et al [2016]). Sadeghi et al [2011] have studied the heat transfer due to a fully developed electroosmotic flow of Phan-Thien-Tanner (PTT) and FENE-P viscoelastic fluids under the Debye-Huckel linearization and shown that the viscous dissipation effect is important for low values of viscoelastic parameter and Debye layer thickness.…”