Novel high step up DC/DC converters with reduced switch voltage stress

In this paper, a novel step up DC/DC converter with reduced switch voltage stress is introduced firstly. The proposed converter is analyzed in steady state and is compared with other DC/DC converters with equal number of components. The voltage stress on all switches is lower than the output voltage. Then, it is shown that the voltage transfer gain can be increased considerable by replacing one of its inductor with two types of switched inductor voltage multiplier cell. Therefore, high step up switched inductor DC/DC converters are realized. The operations of the proposed converters are verified using the simulation result

Effect of magnetic field on thermo-physical and hydrodynamic properties of different metals-decorated multi-walled carbon nanotubes-based water coolants in a closed conduit

In this paper, the thermo-physical and hydrodynamic properties of heat transfer nanofluids containing metal nanoparticles-decorated multi-wall carbon nanotube (MWCNT) are reported. To this end, Cu-decorated MWCNT, Fe-decorated MWCNT, and Ni-decorated MWCNT (covalently functionalized samples) were synthesized with pre-functionalization with the aspartic acid as the hydrophilic chain. To have a comprehensive comparison, water-based non-covalently functionalized MWCNT nanofluids were also synthesized. A significant increase in the thermal and electrical conductivities of heat transfer nanofluids containing metal nanoparticles-based MWCNT as compared to the non-covalently functionalized sample as well as water has been determined at the same operational conditions. All the prepared nanofluids are stable and the viscosity and density remained approximately the same after loading additives. The present paper also focused on the study of the role of weight concentrations of additives, flow rate and thermo-physical properties of the prepared nanofluids on the convective heat transfer rate and hydrodynamic performances in the laminar flow. Further, the convective heat transfer coefficient, pressure drop, friction factor, performance index and pumping power variation were also investigated under applied magnetic field, which improves the overall thermal performance of the closed conduit insignificantly