An experimental investigation was conducted to study the average and the fully-developed heat (mass) transfer coefficients in a rectangular smooth duct and a duct with repeated-baffle blockages. The focus of attention in this work is the conventional correlation Nu / Nufd 1 + C / ( X / D ) for the average heat transfer coefficient. It was shown that for relatively short ducts, the coefficient C...

this paper describes the theoretical and experimental investigations of the key components and also the performance analysis of a rotary wheel for using as a solid desiccant dehumidifier and also indirect evaporator cooling system. solid desiccants have long been used in dehumidification and cooling systems for energy efficiency or reduce electricity. although many mathematical models on the ro...

In this article, stream flow effectivness is based on hydraulic network studied in the shell-side of a shell and tube heat exchange as a case study. For an appropriate heat exchangers rating design to meet a specified duty, it's better to consider each stream flow separately. Using the hydraulic network principals, a set of the correlations for calculating different stream flow rates in the cro...

The presence of particles in liquid-solid fluidized beds enhances the bed heat transfer, because the movement of the particles leads to an increased turbulence in the system. Moreover, the violent movement of the particles has a positive effect on fouling of the heat transfer surface. The aim of this investigation was to perform systematic measurements of bed voidage and heat transfer coeff...

One way to increase the heat transfer is to use perforated twisted tapes with different hole diameters, which largely improve heat transfer with an increase in the heat transfer area at the constant volume and more mixed flow. In the previous studies, the effect of nanofluids with perforated twisted tapes is less studied. In this work, the performance of water / iron oxide nanofluid in a double...

Industrial demands for more compact heat exchangers are a motivation to find new technology features. Electrohydrodynamics (EHD) is introduced as a promising phenomenon for heat transfer enhancement mechanisms. Similar to any new technology, EHD has not been understood completely yet and requires more fundamental studies. In boiling phase change phenomena, nucleation is the dominant mechanism i...

Abstract   An empirical investigation was carried out to study convective heat transfer of nanofluid flow inside an inclined copper tube under uniform heat flux condition. Required data are acquired for laminar and hydrodynamically fully developed flow inside round tube. The stable CuO-base oil nanofluid with different nanoparticle weight fractions of 0.5%, 1% and 2% was produced by means of ul...

The simulation of heat and moisture transfer represents an essential resource in designing energy efficient buildings. In this paper a time-dependent wall model, consisting of several homogeneous domains, with third-type boundary conditions imposed on the surfaces, is implemented in the COMSOL Multiphysics environment. Temperature and moisture content is calculated inside the construction for d...

The study is aimed at quantifying the relative contribution of key heat transfer modes in lyophilization. Measurements of vial heat transfer rates in a laboratory-scale freeze-dryer were performed using pure water, which was partially sublimed under various conditions. The separation distance between the shelf and the vial was systematically varied, and sublimation rates were determined gravime...

The excellent performance of fluidized bed heat exchangers is due to the interaction between particles and heat transfer surface and to the mixing effects in the viscous sublayer. In this paper, the results of experimental investigations on heat transfer for a wide range of Newtonian and non-Newtonian (shear-thinning power law) fluids are presented. New design equations have been developed ...