Pulsating flow in a channel filled with a porous medium under local thermal non-equilibrium condition: an exact solution

Journal of Thermal Analysis and Calorimetry - The present work investigates analytically the problem of forced convection heat transfer of a pulsating flow, in a channel filled with a porous medium...     

MHD forced convection of nanofluid flow in an open-cell metal foam heatsink under LTNE conditions

Journal of Thermal Analysis and Calorimetry - In this paper, nanofluid forced convective heat transfer through an open-cell metal foam heatsink under a uniform heat flux, numerically has been...     

Second law analysis for nanofluid flow in mini-channel heat sink with finned surface: a study on fin geometries

Journal of Thermal Analysis and Calorimetry - In this numerical work, a second law analysis is carried out for the nanofluid flow and heat transfer in the mini-channel with finned surface. The...     

Experimental examination of the cooling performance of a cylindrical microchannel heat sink with straight and sinusoidal fins and alumina nanofluid coolant

Journal of Thermal Analysis and Calorimetry - Miniaturization of the electronic devices and dissipation of the heat generated during the operations within such equipment are of the most important...     

Computational analysis of heat transfer in a PEM fuel cell with metal foam as a flow field

Journal of Thermal Analysis and Calorimetry - Thermal management of proton-exchange membrane (PEM) fuel cell has an important effect on the overall cell performance. In this paper, metal foams as...     

Numerical study of laminar pulsed impinging jet on the metallic foam blocks using the local thermal non-equilibrium model

Journal of Thermal Analysis and Calorimetry - In this study, thermal performance of an impingement jet with the presence of porous block is numerically investigated. The study is comprised of two...     

Heat transfer and fluid flow of pseudo-plastic nanofluid over a moving permeable plate with viscous dissipation and heat absorption/generation

Journal of Thermal Analysis and Calorimetry - The purpose of the present study is investigating the heat transfer of non-Newtonian pseudo-plastic nanofluid flow on a moving permeable flat plate...     

Numerical analysis of effect of nanofluid and fin distribution density on thermal and hydraulic performance of a heat sink with drop-shaped micropin fins

Journal of Thermal Analysis and Calorimetry - In the present study, the effect of nanofluid and distribution density of fin on thermal–hydraulic performance of a heat sink with drop-shaped...     

Turbulent heat transfer and fluid flow of alumina nanofluid inside three-lobed twisted tube

Turbulent flow characteristics and heat transfer applications of a twisted heat exchanger with 3-lobed cross section along with Y-tape insert are numerically studied. The working fluids for the simulations are pure water and water–Al₂O₃ nanofluid using two-phase mixture model. The study is carried out for various nanofluid volume fractions of 0.01, 0.02 and 0.03 with Reynolds number in the range of 5000–20,000. The effect of nanoparticles in heat transfer augmentation for smooth and lobed tubes is discussed based on presenting the highest thermal performance, which is a relation between heat transfer rate and pressure loss. Results show that implementing the twisted tube with Y-tape insert enhances the heat transfer more than the twisted tube. Relative Nusselt numbers for twisted tubes decrease with Reynolds number in comparison with the plain tube. Turbulent intensity, swirl number and tangential velocity of twisted tube with insert are higher than empty twisted tube indicating that inserting the Y-tape intensifies the turbulence and disturbs the fluid flow further. On the other hand, although the twisted tube increases the pressure drop more than plain tube, the case with Y-tape drastically increases the friction factor. So, the thermal performance of twisted tube with insert is lower than empty twisted tube. Adding nanoparticles to the base fluid has different influence on the investigated cases. It augments the relative Nusselt number inside plain tube and empty twisted tube with slight increment in friction factor. Increasing the nanoparticles concentration enhances the heat transfer rates for these cases while it does not increase the relative Nusselt number inside twisted tube with Y-tape insert at high Reynolds number and nanoparticle concentration. Moreover, it can be found that twisted tube with or without Y-tape insert is more efficient at low Reynolds number in comparison with the plain tube.

     

The effect of using nanofluid flow into a porous channel in the CPVT under transient solar heat flux based on energy and exergy analysis

Journal of Thermal Analysis and Calorimetry - Concentrator photovoltaic thermal system is one of the heat and power generation systems that have received special attention in recent decades. In...     

Similarity solution of air and nanofluid impingement cooling of a cylindrical porous heat sink

Journal of Thermal Analysis and Calorimetry - In the present paper, a numerical study on flow and heat transfer of air/nanofluid impinging jet flow through a cylindrical porous heat sink has been...     

Experimental investigation of nanofluid stability on thermal performance and flow regimes in pulsating heat pipe

Pulsating heat pipe (PHP) is a type of wickless heat pipe that has a simple structure and an outstanding thermal performance. Nanofluid is a type of fluid in which nanoparticles are dispersed in a base fluid and have generally a better thermal conductivity in comparison with its base fluid. In this article, the performance of a nanofluid PHP is investigated. Graphene/water nanofluid with a concentration of 1 mg mL^?1 and TiO₂ (titania)/water nanofluid with a concentration of 10 mg mL^?1 are used as the working fluids. To simultaneously investigate the thermal performance and flow regimes in the PHP, a one-turn copper PHP with a Pyrex glass attached to its adiabatic section is used. A one-turn Pyrex PHP is also used to fully visualize flow patterns in the PHP. Our results show that the material for the fabrication of a PHP and temperature of the working fluid are the most important parameters that affect the stability of a nanofluid in the PHP. The more stable nanofluid keeps its stability in the cupper PHP, while the less stable nanofluid starts to aggregate right after the injection to the cupper PHP. The more stable nanofluid has a better thermal performance than water, while the less stable nanofluid has a worse thermal performance than water. In the case of flow regimes, no significant differences are observed between the nanofluid PHP and the water PHP which is different from the previous observations. These results can help researchers to choose the best working fluid for PHPs.

     

Spectral analysis of a fluid under thermal constraint

Abstract

A spectral analysis is presented to investigate the onset of the convective instability in a fluid subject to a linear temperature gradient. The hydrodynamic theory is developed for the case of a binary system, where the concentration of one of the components is small. Therefore the present results will be applicable to the case of a Brownian system. We consider exclusively those modes which correspond to the central components of the spectral distribution, i.e., the diffusion mode and the thermal diffusivity mode. One finds that those modes are effected by the presence of the external temperature gradient in such a way that the spectrum of the scattered light should exhibit an important narrowing of the thermal diffusivity peak and a slight narrowing of the diffusion peak when approaching the convective instability critical point. Only the thermal diffusivity mode is affected in the limit of a pure fluid     

Irreversibility of mixed convection peristalsis flow of nanofluid under the influence of heat mass flux with slip and thermal radiation

Journal of Thermal Analysis and Calorimetry - This analysis communicates the thermophoretic and Brownian motion aspects in magneto-peristalsis with variable viscosity characteristics of viscous...     

Semi-analytical study of impingement cooling of metal foam heat sinks of CPUs with air and hydrogen jets under LTNE condition

Journal of Thermal Analysis and Calorimetry - In this paper, a mathematical model for heat transfer in a heat sink covered by an open-cell metal foam under impinging jet flow is presented. Hydrogen...     

MHD heat and mass transfer stagnation point nanofluid flow along a stretching sheet influenced by thermal radiation

Journal of Thermal Analysis and Calorimetry - The objective of the present study seems to be to explore the numerical findings of the steady incompressible 2-D MHD stagnation point flow of...     

Heat transfer exaggeration and entropy analysis in magneto-hybrid nanofluid flow over a vertical cone: a numerical study

Journal of Thermal Analysis and Calorimetry - Entropy analysis is closely scrutinized for unsteady mixed convection in magneto-hybrid nanofluid (Cu–Fe $$_3$$ O $$_4$$ –water) flow over...     

Two-phase simulation of nanofluid flow in a heat exchanger with grooved wall

Journal of Thermal Analysis and Calorimetry - The aim of this paper is to achieve a smaller and cheaper heat exchanger with similar performance. To fulfill this demand, ANSYS-Fluent software and...     

Thermal analysis of nanofluid flow containing gyrotactic microorganisms in bioconvection and second-order slip with convective condition

Journal of Thermal Analysis and Calorimetry - Bioconvection in magneto-nanoliquid embedded with gyrotactic microorganisms across an elongated sheet with velocity slip of second order is addressed....     

Heat flow,heat capacity and thermal resistance of localized surfaces of the human body using a new calorimetric sensor

Journal of Thermal Analysis and Calorimetry - A non-invasive sensor equipped with a programmable thermostat has been developed to assess in vivo the heat flow transmitted by conduction from human...