in the current investigation, fe3o4 water-based nanofluids were synthesized to examine the effect of an alternative 3-d external magnetic field on its thermal behavioral pattern. a solvothermal method was used to prepare the magnetite nanoparticles. to characterize the nanoparticles, the study employed transmission electron microscopy, x-ray diffraction, fourier transform infrared spectroscopy,...

leather manufacturing involves a crucial energy-intensive drying stage in the finishing process to remove its residual moisture. determining drying characteristics of leather is vitally important so as to optimize the drying stage. this paper describes an analytical way for determination of the drying characteristics of leather. the model presented, is based on fundamental heat and mass transfe...

This paper examines the method to simulate heat balances on building and urban surfaces by combining the 3D CAD-based thermal environment simulator with 3D steady RANS CFD simulations. The simulation results of the distribution of convective heat transfer coefficient in an urban canyon model are compared with that of a wind tunnel experiment. The effects of building geometries, including verand...

To learn about cooling of gas quenched batches, this paper reports on numerical predictions of local and average convective heat transfer coefficients, and overall pressure drops, on batches of five axially aligned, constant temperature, short cylindrical disks 25 cm diameter, 5 cm thickness with and without a concentric hole, with interdisk spacings of 5–20 cm, in axial turbulent flows of 20 b...

In this paper theoretical estimations of boundary layer thickness and heat transfer coefficient is examined using Computational Fluid Dynamics (CFD) for laminar air flow. The feasibility and accuracy of using CFD to calculate convective heat transfer coefficients is examined. A grid sensitivity analysis is performed for the CFD solutions, and it is used to determine the convective heat transfer...

Nanofluids, in which nano-sized particles (typically less than 100 nm) are suspended in liquids, have emerged as a possible effective way of improving the heat transfer performance of common fluids. In this paper a numerical study is performed to analyze the wall shear stress and heat transfer coefficient of γAl2O3-water nanofluids under laminar forced convection through a circular pipe. It is ...

Engineering MEMS devices using finite element analysis can be very rewarding, provided the analysis is valid, i.e. it accurately simulates reality throughout the desired range of input and resultant imposition upon dependent physical properties and behavior. With respect to FEM’s use in MEMS, it is can be very useful. Doped single crystal silicon is a substance whose material and physical prope...

Improving heat transfer and performance in a radial, finned, shell and tube heat exchanger is studied in this study. According to the second law of thermodynamics, the most irreversibilities of convective heat transfer processes are due to fluid friction and heat transfer via finite temperature difference. Entransy dissipations are due to the irreversibilities of convective heat transfer. There...

Heat transfer in rough circular cylinder microfins is studied and a new analytical model is developed. Assuming Gaussian isotropic surface roughness, it is shown that both cross-sectional and surface areas ofmicrofins increase by increasing roughness. Consequently, an enhancement is observed in the heat transfer rate and thermal performance of microfins. The effect of roughness is more profound...