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Papers by Patrice Estellé

Applied Rheology, 2009

... Arnaud Perrot, Yannick Mélinge, Damien Rangeard, Patrice Estellé, Christophe Lanos. ... In th... more ... Arnaud Perrot, Yannick Mélinge, Damien Rangeard, Patrice Estellé, Christophe Lanos. ... In the present work, we propose to link rheology and soil mechanics concepts (consolidation theory,Darcy's law) to reach a simple criterion which predicts the extrusion ability of the mortar. ...

Rheologica Acta, 2007

Extrusion is not a common way to form firm cement-based material. Due to material frictional beha... more Extrusion is not a common way to form firm cement-based material. Due to material frictional behaviour drainage phenomenon appears and leads to process blockage. The properties of the extrusion multiphase flow of such specific materials have to be highlighted in order to understand the properties of the process flow. An extrudible mortar is formulated according to extrusion criteria provided by literature tests are developed in order to describe the evolution of the paste undergoing extrusion. To study the relationship between flow properties, extrusion force and material consolidation, a technique based on the measurement of paste hardness in the billet zone is developed. Measurements of the local paste density and flow visualization are also performed. Results show that in the range of used ram velocities, filtration occurs between fluid and solid phases. This creates zones of preferential flow and of non-flowing consolidated material.

Procedia Engineering, 2013

ABSTRACT A new engineering medium, called nanofluid, have attracted a wide range of researches on... more ABSTRACT A new engineering medium, called nanofluid, have attracted a wide range of researches on many processes in engineering applications. Many experimental and theoretical studies on viscosity of nanofluids are controversial and the shear rate dependent viscosity is frequently neglected. The aim of the present work is to investigate the effect of the rheological behavior of aqueous suspensions of carbon nanotubes on the friction factor and the pressure drop in a horizontal tube under laminar and turbulent flow. The particles weight concentration used here is 0.01%. The rheological behavior was measured for a range of temperature from 0°C to 40°C. The results showed that the nanofluids exhibit a shear thinning behavior at very low shear stress. The analysis results of the flow characteristics showed a non-Newtonian behavior under laminar flow and a Newtonian behavior under turbulent flow. Nomenclature f friction coefficient D diameter of horizontal tube (m) g gravitational constant (m/s²) Re Reynolds number Q flow rate (m 3 /s) L length of horizontal tube (m) Greek symbols dynamic viscosity (Pa.s) roughness (mm) concentration (%) density (kg/m 3) P pressure drops (Pa) Subscripts m weight nf nanofluid 0 water s surfactant

Materials and Structures, 2014

 This paper focuses on the determination of the consolidation characteristics of mineral materia... more  This paper focuses on the determination of the consolidation characteristics of mineral materials. The main objectives were to improve measurement accuracy and to reduce test duration. Consolidation characteristics govern fluid migration and the evolution of the properties; compressibility, permeability and consolidation coefficient are required to describe hydro-mechanical behaviour. In this paper, a method of consolidation coefficient determination is proposed.

Applied Thermal Engineering, 2014

The present work focuses on analytical optimization of a rectangular microchannel heat sink using... more The present work focuses on analytical optimization of a rectangular microchannel heat sink using aqueous carbon nanotubes based nanofluid as coolant. The particles weight concentration used in this study is 0.01%. The density, the thermal conductivity and the rheological behavior of the nanofluid are experimentally investigated in order to evaluate the thermal resistance and the pumping power in microchannel under laminar flow. An analytical approach of optimization scheme was applied; it is compiled from a systematic thermal resistance model as an analysis method and the elitist non-dominated sorting genetic algorithm (NSGA2). The effects of the temperature, the channel aspect ratio, the channel wall ratio and the use of aqueous carbon nanotubes based nanofluid on the thermal resistance and the pumping power are investigated. The optimized results showed that use of the nanofluid as a working fluid reduce the total thermal resistance and can enhance significantly the thermal performances of the working fluid at high temperatures.

Journal of Thermal Engineering, 2015

We report in this communication thermal conductivity measurement of carbon nanotubes waterbased n... more We report in this communication thermal conductivity measurement of carbon nanotubes waterbased nanofluids. We consider in particular the influence of nanoparticle volume fraction, temperature, carbon nanotube aspect ratio and different kind of surfactant (SDBS, Lignin, Sodium Polycarboxylate) on thermal conductivity enhancement of nanofluids. In addition, various theoretical thermal conductivity models are presented in an attempt to correlate the experimental data.

... Arnaud Perrot* — Damien Rangeard**—Yannick Mélinge*— Patrice Estellé*— Christophe Lanos ... D... more ... Arnaud Perrot* — Damien Rangeard**—Yannick Mélinge*— Patrice Estellé*— Christophe Lanos ... Dans ce travail, on se propose de relier des concepts de rhéologie et de mécanique des sols (théorie de la consolidation, loi de Darcy) pour aboutir à un critère simple prédisant la ...

International Communications in Heat and Mass Transfer, 2015

We report here the thermal conductivity measurement of carbon nanotubes waterbased nanofluids sta... more We report here the thermal conductivity measurement of carbon nanotubes waterbased nanofluids stabilized by sodium dodecylbenzene sulfonate as a function of volume fraction and temperature. For the first time, we further show the existence of a sharp peak in thermal conductivity at very small volume fraction below theoretical percolation threshold which is temperature independent. This preliminary study evidences the potential of promising and useful nanofluid for practical applications in cooling and energy systems and heat exchangers, as viscosity penalty is obviously vanished at this concentration.

Applied Rheology, 2009

... Arnaud Perrot, Yannick Mélinge, Damien Rangeard, Patrice Estellé, Christophe Lanos. ... In th... more ... Arnaud Perrot, Yannick Mélinge, Damien Rangeard, Patrice Estellé, Christophe Lanos. ... In the present work, we propose to link rheology and soil mechanics concepts (consolidation theory,Darcy's law) to reach a simple criterion which predicts the extrusion ability of the mortar. ...

Rheologica Acta, 2007

Extrusion is not a common way to form firm cement-based material. Due to material frictional beha... more Extrusion is not a common way to form firm cement-based material. Due to material frictional behaviour drainage phenomenon appears and leads to process blockage. The properties of the extrusion multiphase flow of such specific materials have to be highlighted in order to understand the properties of the process flow. An extrudible mortar is formulated according to extrusion criteria provided by literature tests are developed in order to describe the evolution of the paste undergoing extrusion. To study the relationship between flow properties, extrusion force and material consolidation, a technique based on the measurement of paste hardness in the billet zone is developed. Measurements of the local paste density and flow visualization are also performed. Results show that in the range of used ram velocities, filtration occurs between fluid and solid phases. This creates zones of preferential flow and of non-flowing consolidated material.

Procedia Engineering, 2013

ABSTRACT A new engineering medium, called nanofluid, have attracted a wide range of researches on... more ABSTRACT A new engineering medium, called nanofluid, have attracted a wide range of researches on many processes in engineering applications. Many experimental and theoretical studies on viscosity of nanofluids are controversial and the shear rate dependent viscosity is frequently neglected. The aim of the present work is to investigate the effect of the rheological behavior of aqueous suspensions of carbon nanotubes on the friction factor and the pressure drop in a horizontal tube under laminar and turbulent flow. The particles weight concentration used here is 0.01%. The rheological behavior was measured for a range of temperature from 0°C to 40°C. The results showed that the nanofluids exhibit a shear thinning behavior at very low shear stress. The analysis results of the flow characteristics showed a non-Newtonian behavior under laminar flow and a Newtonian behavior under turbulent flow. Nomenclature f friction coefficient D diameter of horizontal tube (m) g gravitational constant (m/s²) Re Reynolds number Q flow rate (m 3 /s) L length of horizontal tube (m) Greek symbols dynamic viscosity (Pa.s) roughness (mm) concentration (%) density (kg/m 3) P pressure drops (Pa) Subscripts m weight nf nanofluid 0 water s surfactant

Materials and Structures, 2014

 This paper focuses on the determination of the consolidation characteristics of mineral materia... more  This paper focuses on the determination of the consolidation characteristics of mineral materials. The main objectives were to improve measurement accuracy and to reduce test duration. Consolidation characteristics govern fluid migration and the evolution of the properties; compressibility, permeability and consolidation coefficient are required to describe hydro-mechanical behaviour. In this paper, a method of consolidation coefficient determination is proposed.

Applied Thermal Engineering, 2014

The present work focuses on analytical optimization of a rectangular microchannel heat sink using... more The present work focuses on analytical optimization of a rectangular microchannel heat sink using aqueous carbon nanotubes based nanofluid as coolant. The particles weight concentration used in this study is 0.01%. The density, the thermal conductivity and the rheological behavior of the nanofluid are experimentally investigated in order to evaluate the thermal resistance and the pumping power in microchannel under laminar flow. An analytical approach of optimization scheme was applied; it is compiled from a systematic thermal resistance model as an analysis method and the elitist non-dominated sorting genetic algorithm (NSGA2). The effects of the temperature, the channel aspect ratio, the channel wall ratio and the use of aqueous carbon nanotubes based nanofluid on the thermal resistance and the pumping power are investigated. The optimized results showed that use of the nanofluid as a working fluid reduce the total thermal resistance and can enhance significantly the thermal performances of the working fluid at high temperatures.

Journal of Thermal Engineering, 2015

We report in this communication thermal conductivity measurement of carbon nanotubes waterbased n... more We report in this communication thermal conductivity measurement of carbon nanotubes waterbased nanofluids. We consider in particular the influence of nanoparticle volume fraction, temperature, carbon nanotube aspect ratio and different kind of surfactant (SDBS, Lignin, Sodium Polycarboxylate) on thermal conductivity enhancement of nanofluids. In addition, various theoretical thermal conductivity models are presented in an attempt to correlate the experimental data.

... Arnaud Perrot* — Damien Rangeard**—Yannick Mélinge*— Patrice Estellé*— Christophe Lanos ... D... more ... Arnaud Perrot* — Damien Rangeard**—Yannick Mélinge*— Patrice Estellé*— Christophe Lanos ... Dans ce travail, on se propose de relier des concepts de rhéologie et de mécanique des sols (théorie de la consolidation, loi de Darcy) pour aboutir à un critère simple prédisant la ...

International Communications in Heat and Mass Transfer, 2015

We report here the thermal conductivity measurement of carbon nanotubes waterbased nanofluids sta... more We report here the thermal conductivity measurement of carbon nanotubes waterbased nanofluids stabilized by sodium dodecylbenzene sulfonate as a function of volume fraction and temperature. For the first time, we further show the existence of a sharp peak in thermal conductivity at very small volume fraction below theoretical percolation threshold which is temperature independent. This preliminary study evidences the potential of promising and useful nanofluid for practical applications in cooling and energy systems and heat exchangers, as viscosity penalty is obviously vanished at this concentration.