Amirkabir University of Technology

About: Amirkabir University of Technology is a education organization based out in Tehran, Iran. It is known for research contribution in the topics: Nonlinear system & Finite element method. The organization has 15254 authors who have published 31165 publications receiving 487551 citations. The organization is also known as: Tehran Polytechnic & Tehran Polytechnic University.

Transport properties of multi-layer fabric based on electrospun nanofiber mats as a breathable barrier textile material

Abstract: Layered fabric systems with an electrospun nanofiber web layered onto a sandwich of woven fabric were developed to examine the feasibility of developing breathable barrier textile materials. Some parameters of nanofiber mats, including the time of electrospinning and the polymer solution concentration, were designed to change and barrier properties of specimens were compared. Air permeability, water vapor transmission, and water repellency (Bundesmann and hydrostatic pressure tests) were assessed as indications of comfort and barrier performance of different samples. These performances of layered nanofiber fabrics were compared with a well-known water repellent breathable multi-layered fabric (Gortex).Multi-layered electrospun nanofiber mats equipped fabric (MENMEF) showed better performance in windproof property than Gortex fabric. Also, water vapor permeability of MENMEF was in a range of normal woven sport and work clothing. Comparisons of barrier properties of MENMEF and the currently available PTFE c...

CFD analysis of thermal and hydrodynamic characteristics of hybrid nanofluid in a new designed sinusoidal double-layered microchannel heat sink

Abstract: In this study, laminar and steady flow of hybrid Al2O3–Cu/water nanofluid is done for volume fraction of solid nanoparticles 0–2% in a double-layered microchannel with sinusoidal walls. The results of this study show that the sinusoidal shape of the microchannel walls has a strong effect on increasing heat transfer, and increasing solid nanoparticle volume fraction in base fluid can have a significant difference for increasing Nusselt number, so that the value of Nusselt number for solid nanoparticles volume fraction of 2% for Re = 50, 300, 700 and 1200 experiences 23%, 22% 19% and 13% increase compared with the base fluid. By increasing fluid viscosity, the shear stress especially in the areas close to wall and in fluid layers is increased and this factor can increase pressure drop in higher solid nanoparticles volume fractions. The static temperature profiles are affected by hot surfaces and their sinusoidal shapes in lower Reynolds numbers, and the curve for temperature of flow centerline for Re = 700 and 1200 is straight lines. Therefore, the usage of it for Reynolds numbers above 700 is not recommended.