Heat transfer intensification in microchannel by induced-charge electrokinetic phenomenon: a numerical study
- PDF / 5,648,251 Bytes
- 13 Pages / 595.276 x 790.866 pts Page_size
- 57 Downloads / 169 Views
Heat transfer intensification in microchannel by induced‑charge electrokinetic phenomenon: a numerical study Soroush Najjaran1 · Saman Rashidi2 · Mohammad Sadegh Valipour1 Received: 29 July 2020 / Accepted: 15 September 2020 © Akadémiai Kiadó, Budapest, Hungary 2020
Abstract In this numerical investigation, the induced-charge electrokinetic phenomenon is used to intensify the convective heat transfer rate in the microchannel. The electrically conductive obstacles are placed in the microchannel for inducing the vortices and subsequently, enhancing the mixing of fluid and convective heat transfer rate. The results gained by the current numerical simulation are benchmarked with the other data available in the literature to ensure about the precision of the numerical solver. The influences of several parameters, including the length, location, and number of conductive obstacles and the electric field intensity, on the convective heat transfer rate are studied. The outcomes indicate that the convective heat transfer coefficient achieved for the case of the microchannel equipped with the electrically conductive obstacle is about 18 times larger as compared with the case of the empty microchannel without placing the electrically conductive obstacle. It is suggested to install the conductive obstacle near the inlet of the microchannel to achieve a higher heat transfer rate. The convective heat transfer coefficient increases up to 215.4% inside the microchannel as length of the conductive obstacle is increased from 15 to 35 µm. Finally, the normalized convective heat transfer coefficient improves about 743.4% when the electric field strength is boosted from 20 to 60 V cm−1. Keywords Induced-charge electrokinetic phenomenon · Convective heat transfer · Mixing · Vortices · Strength · Microchannel List of symbols C Concentration cp Specific heat capacity D Diffusion coefficient e Fundamental charge of electrons, (1.602 × 10−19 C) ⇀ E External applied electric field h Obstacle width hx Local convective heat transfer coefficient h̄ L Mean convective heat transfer coefficient H Microchannel height k Thermal conductivity kB Boltzmann constant, 1.38 × 10−23 J/K l Obstacle length L Microchannel length MI Mixing parameter * Mohammad Sadegh Valipour [email protected] 1
Faculty of Mechanical Engineering, Semnan University, Semnan 35131‑19111, Iran
Department of Energy, Faculty of New Science and Technologies, Semnan University, Semnan, Iran
2
n0 Ionic concentration in bulk solutions P Pressure Pa Ambient pressure q″ Heat flux t Time T Temperature Tb Bulk temperature Tw Temperature on microchannel wall ⇀ u Velocity ū Average velocity z Amount of ionic valence Greek symbols ρ Density λD Thickness of electric double layer μ Viscosity ρe Local net charge density ε0 Dielectric constant for vacuum ε Dielectric constant for medium εw Dielectric constant, εw = ε × ε0 ζ Zeta potential ζw Zeta potential on microchannel surface ζi Induced zeta potential on conductive surfaces
13
Vol.:(01234
Data Loading...
