Islamic Azad University

About: Islamic Azad University is a education organization based out in Tehran, Iran. It is known for research contribution in the topics: Population & Catalysis. The organization has 83635 authors who have published 113437 publications receiving 1275049 citations. The organization is also known as: Azad University.

Experimental study on synthesis, stability, thermal conductivity and viscosity of Cu–engine oil nanofluid

Abstract: In this study, a colloidal suspension consists of Cu nanoparticles and engine oil has been made by a one- step method known as Electrical Explosion of Wire (E.E.W) in three different weight concentrations of 0.2%, 0.5% and 1%. After studying physical properties of the applied nanofluids via high resolution transmission electron microscopy and measuring zeta potential for the stability analysis, thermo-physical properties such as thermal conductivity and viscosity, have been experimentally studied. Measured data of thermal conductivity and viscosity of applied nanofluids have been compared to the predicted ones through the proposed correlations for thermal conductivity and viscosity of oil based nanofluids and acceptable agreements between the two have been achieved. The range of thermal conductivity of higher weight concentration was measured to be from 0.153 to 0.17 (W/m. K) in the temperature range from 40 C to 100 C, while pure engine oil exhibits a decreasing trend in contradictory. Secondly, viscosity variations through capturing Newtonian or non- Newtonian behavior of utilized nanofluids has been investigated. The viscosity range for higher weight concentration nanofluid was observed from 235 cP to 35 cP in the applied temperature range. Finally, thermal conductivity and viscosity enhancements of 49% and 37% were observed for 1% weight fraction of utilized nanofluids.

New exact solutions of nonlinear conformable time-fractional Boussinesq equations using the modified Kudryashov method

Abstract: In this paper, the nonlinear Boussinesq equations with the conformable time-fractional derivative are solved analytically using the well-established modified Kudryashov method. As a consequence, a number of new exact solutions for this type of equations are formally derived. It is believed that the method is one of the most effective techniques for extracting new exact solutions of nonlinear fractional differential equations.

The effects of different nano particles of Al2O3 and Ag on the MHD nano fluid flow and heat transfer in a microchannel including slip velocity and temperature jump

Abstract: The forced convection of nanofluid flow in a long microchannel is studied numerically according to the finite volume approach and by using a developed computer code. Microchannel domain is under the influence of a magnetic field with uniform strength. The hot inlet nanofluid is cooled by the heat exchange with the cold microchannel walls. Different types of nanoparticles such as Al2O3 and Ag are examined while the base fluid is considered as water. Reynolds number are chosen as Re=10 and Re=100. Slip velocity and temperature jump boundary conditions are simulated along the microchannel walls at different values of slip coefficient for different amounts of Hartmann number. The investigation of magnetic field effect on slip velocity and temperature jump of nanofluid is presented for the first time. The results are shown as streamlines and isotherms; moreover the profiles of slip velocity and temperature jump are drawn. It is observed that more slip coefficient corresponds to less Nusselt number and more slip velocity especially at larger Hartmann number. It is recommended to use Al2O3-water nanofluid instead of Ag-water to increase the heat transfer rate from the microchannel walls at low values of Re. However at larger amounts of Re, the nanofluid composed of nanoparticles with higher thermal conductivity works better.