TY - JOUR
T1 - Thermal boundary layer depletion in minichannels by electrohydrodynamic conduction pumping
AU - Selvakumar, R. Deepak
AU - Lee, Hyoungsoon
N1 - Publisher Copyright:
© 2023 Elsevier Ltd
PY - 2023/7/25
Y1 - 2023/7/25
N2 - The article presents a numerical analysis of two-dimensional laminar flow and heat transfer in a minichannel with flat plate electrode pairs periodically flushed to the bottom wall. The two-way coupled governing equations of flow, heat transfer, electric potential and charge conservation are solved using the opensource finite-volume framework of OpenFOAM. Two cases of the minichannel at completely horizontal (case A) and 90° bent (case B) configurations are considered. The inlet laminar flow with Reynolds number varying from 10 to 1000 has been taken into account. The applied electric potential is varied in three steps 0, 0.5 and 1 kV. Electrohydrodynamic (EHD) conduction pumping due to the residual conductivity of the working fluid and the electric-field enhanced dissociation of free charges generate vortices in the proximity of electrodes. The flow and thermal performance of the minichannel in the presence of EHD conduction induced vortices are quantified in terms of pressure drop, Nusselt number and a performance factor (which is a combined function of pressure drop and Nusselt number). The vortices generated by EHD conduction pumping phenomenon deplete the thermal boundary layer, aid mixing and enhance the heat transfer. The mean and local Nusselt numbers are notably increased with only a minimal raise in pressure drop. In both the configurations of the minichannel, the performance factor is greater than 1 for the entire parameter space considered in this study. However, the thermal boundary layer depletion and heat transfer enhancement is prominent at low Reynolds number flows. The maximum drop in performance factor from case A to case B is only 18.5%. Results of this study indicate that EHD conduction pumping is a potential technique to enhance heat transfer in minichannels with minimum additional power consumption.
AB - The article presents a numerical analysis of two-dimensional laminar flow and heat transfer in a minichannel with flat plate electrode pairs periodically flushed to the bottom wall. The two-way coupled governing equations of flow, heat transfer, electric potential and charge conservation are solved using the opensource finite-volume framework of OpenFOAM. Two cases of the minichannel at completely horizontal (case A) and 90° bent (case B) configurations are considered. The inlet laminar flow with Reynolds number varying from 10 to 1000 has been taken into account. The applied electric potential is varied in three steps 0, 0.5 and 1 kV. Electrohydrodynamic (EHD) conduction pumping due to the residual conductivity of the working fluid and the electric-field enhanced dissociation of free charges generate vortices in the proximity of electrodes. The flow and thermal performance of the minichannel in the presence of EHD conduction induced vortices are quantified in terms of pressure drop, Nusselt number and a performance factor (which is a combined function of pressure drop and Nusselt number). The vortices generated by EHD conduction pumping phenomenon deplete the thermal boundary layer, aid mixing and enhance the heat transfer. The mean and local Nusselt numbers are notably increased with only a minimal raise in pressure drop. In both the configurations of the minichannel, the performance factor is greater than 1 for the entire parameter space considered in this study. However, the thermal boundary layer depletion and heat transfer enhancement is prominent at low Reynolds number flows. The maximum drop in performance factor from case A to case B is only 18.5%. Results of this study indicate that EHD conduction pumping is a potential technique to enhance heat transfer in minichannels with minimum additional power consumption.
KW - EHD conduction pumping
KW - Electrohydrodynamics
KW - Flexible electronics
KW - Minichannel
KW - Thermal management
UR - http://www.scopus.com/inward/record.url?scp=85159612101&partnerID=8YFLogxK
U2 - 10.1016/j.applthermaleng.2023.120758
DO - 10.1016/j.applthermaleng.2023.120758
M3 - Article
AN - SCOPUS:85159612101
SN - 1359-4311
VL - 230
JO - Applied Thermal Engineering
JF - Applied Thermal Engineering
M1 - 120758
ER -