A comprehensive investigation of nanofluid conjugate heat transfer in a microchannel under MHD effect

The present paper investigates the flow field and heat transfer in a microchannel with incorporating surface hydrophobicity and considering its thickness. The microchannel is under partial magnetic field (MF), which is applied to the top thermal-insulated wall in Hartmann numbers 0 to 30. The results show that at Ha = 0, viscous dissipation (VD) and heat transfer decrease with increasing slip coefficient. Also, raising the Hartmann number (Ha) increases the friction coefficient. The Nusselt number (Nu) reaches its highest value at Ha = 20 for all cases, but then, as the Ha increases, the average Nu reduces

Peristaltic flow analysis of thermal engineering nano model with effective thermal conductivity of different shape nanomaterials assessing variable fluid properties

The current study is connected to a recent investigation regarding temperature-dependent viscous flow for various-shaped nanoparticles in a flexible tube. For velocity/pressure gradient/temperature, precise solutions have been determined. Cylindrical coordinates have been used to simulate the main flow problem, and the lubrication approximation method has been used to reduce the flow equations to ordinary differential equations (ODEs). For easier understanding, results are graphically discussed. Additionally, it can be seen that platelet-shaped particles have a smaller velocity field than brick- and cylinder-shaped particles. Further it is analyzed that if we add the specific brick-shaped nanoparticles to the fluid, the thermal conductivity of the fluid improves

Toward tuning flow charecteristics in microchannel by nanotechnology and electrokinetic: Numerical simulation of heterogenous electroosmotic flow

Nanotechnology in recent years helps researcehers to design flow rate and profile in microsized channel via making surface charge heterogenous. This paper numerically simulates the electroosmotic flow inside a microchannel with non-uniform Zeta potential (ZP). The problem is a two-dimensional, incompressible, steady, and laminar channel flow between two parallel plates. The numerical results show that the flow rate changes compared to a constant ZP by ascending, descending, and parabolic modifications of the wall ZP at the mid-length of the microchannel. Results show that flow volume rate increases by microchannel width from 4 mm3/s to 6.5 mm3/s in best condition

Synthesis, characterization, and enhanced hydrogen generation from NaBH4 methanolysis of highly dispersed bimetallic PdNi nanoparticles supported on Vulcan carbon

In this presented work, the bimetallic palladium-nickel nanoparticles (PdNi NPs) supported by Vulcan carbon (VC) were synthesized by chemical method. The morphological structure of the synthesized PdNi@VC NPs was determined by ultraviolet-visible spectrum (UV–Vis), Fourier infrared spectrometry (FTIR), transmission electron microscopy (TEM), and X-ray diffraction (XRD) characterization performed. According to the characterization results obtained, the size of the NPs was found to be 8.523 ± 2.036 nm. Then, hydrogen production efficiencies were tested according to different temperatures, substrate, and catalyst concentrations. Finally, the reusability test was performed. According to the results obtained, the hydrogen average production efficiency of NPs was calculated as 84%. The activation energy (Ea), enthalpy (ΔH), and entropy (ΔS) values of the catalyst were found to be 54.2 kJ/mol, 51.7 kJ/mol, -134.5 J/mol.K, respectively. This study guides the new catalytic energy production studies to be carried out on nanotechnological platforms. These synthesized nanoparticles can be developed to be an efficient catalyst for hydrogen generation as an alternative energy source