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This paper introduces a numerical analysis of the acoustic streaming phenomenon using the lattice Boltzmann method (LBM). This study aims to investigate the flow created by the sound wave propagation in water. The waves are emitted by a linear source situated in the middle of the left surface of a rectangular cavity. This acoustic streaming study can be applied in the photovoltaic silicon purification field whose final objective is the participation in the manufacture of photovoltaic panels. This work is particularly interested in the study of Eckart streaming produced by the dissipation of the waves acoustic energy in the medium. An analytical analysis is also performed to confirm the validity of the numerical approach.

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In this paper, boiling and condensation phenomena are described on walls with mixed wettability using a hybrid thermal model with multiple relaxation times of the Boltzmann lattice type. We start this study by validating our code. To do so, different simulations are performed namely the spreading of a liquid droplet on an adjustable wettability surface by varying its density, the surface tension for different temperatures around the critical point using Laplace’s law which is used to compute the characteristic parameters (Taylor wavelength λ d , characteristic length l 0 and characteristic time t 0 ), the evaporation of a liquid droplet is evaluated in compraison with the literature work for constant thermal conductivity values. Subsequently, the power law is verified by processing the growth of a liquid droplet for three different cases of wettability. On the other hand, we study the behavior of condensation and boiling processes and their interactions between the boundaries of the solid surface in which they occur. For this purpose, the cavity walls are considered wetting in some areas and non-wetting in others. The results show different behaviors depending on the zones of the walls.

The purpose of this paper is to develop a numerical scheme based on the MRT-D2Q9 model for fluid velocity and the MRT-D2Q5 cross model for the temperature to study the natural convection phenomenon in a differentially heated square enclosure containing air. The present work aims to prove the accuracy and the capacity of this model to predict the thermodynamics phenomena. In fact, the main goal consists to demonstrate the efficiency of the double population approach based on new MRT-LBM scheme in the assessment of laminar and transitional flows in natural convection case for different Rayleigh numbers (up to 108). The numerical results of the present work were successfully checked for accuracy and are in satisfactory agreement with those available in literature. The results analysis shows that the present method has proven its ability to handle similar problem.

A comprehensive numerical study has been conducted to investigate two-dimensional, steady heat transfer of natural convection in a divided enclosure of high aspect ratio. The vertical walls of the enclosure are maintained at different temperatures, while the horizontal walls are adiabatics. A numerical hybrid scheme with lattice Boltzmann for fluid velocity and finite difference for the temperature is adopted. Parametric studies of the effects of aspect ratio, number and length of partitions attached to the cold wall of the enclosure on heat transfer and fluid flow have been performed. Copyright © 2007 John Wiley & Sons, Ltd.

A numerical hybrid lattice-Boltzmann equation finite-difference is used to study the radiation–natural convection phenomena in a square cavity, differentially heated, with partition of finite thickness and varying height located vertically at the center of the cavity. The results obtained show that the radiation exchange produces a rise in the heat transfer. The average Nusselt number and the throughflow strength increase when the gap width ( w ), maximal difference temperature (Δ T ) and cavity width ( L ) get larger. Effects of different parameters on streamlines, temperature fields, average Nusselt number and throughflow strength are discussed.

In this paper, a numerical investigation of laminar convective flows in a differentially heated, square enclosure with a heat-conducting cylinder at its center, is carried out. The flow and the temperature are computed using respectively the lattice Boltzmann equation and finite-difference with suitable coupling to take natural convection into account. The investigation is performed for Pr = 0.71 , Rayleigh numbers of Ra = 10 3 – 10 6 and temperature-difference ratio of Δ T ∗ = 0 – 50 . The average hot and cold walls Nusselt numbers, the flow and temperature fields are presented and discussed. For a constant Ra, the average Nusselt number at the hot and cold walls ( Nu h and Nu c ) vary linearly with Δ T ∗ : Nu h decreases with Δ T ∗ while Nu c increases with Δ T ∗ .

This study presents a numerical investigation of laminar natural convection heat transfer in an inclined enclosure, differentially heated, with inclined partitions attached to its hot wall. The top and bottom walls of the cavity are insulated. Numerical solutions are obtained by using the hybrid lattice-Boltzmann method finite-difference. Effects of partition length, partition inclination angle, partitions number and aspect ratio cavity are studied for Prandtl number 0.71 and cavity inclination angles of 45 ∘ and 90 ∘ . Rayleigh numbers considered are 5 × 10 5 for a square cavity and 10 4 for a cavity with an aspect ratio equal to 6. Results are reported in terms of isotherms, streamlines, local and average Nusselt numbers.

In the present work, a numerical study of the effect of a single and multiple partitions on heat transfer phenomena in an inclined square cavity, differentially heated, is carried out for Pr = 0.71 and Rayleigh numbers of Ra = 10 3 –10 6 . The partitions are attached to the cold wall of the cavity. Numerical coupling between the lattice Boltzmann equation and finite-difference for the temperature is used to solve this problem. The investigation is performed for various inclination angles and gap widths W . At lower Ra ( Ra ⩽ 10 5 ), the average hot wall Nusselt number Num is higher in inclined cavities than in vertical ones; while at larger Ra ( Ra = 10 6 ), the opposite occurs. In vertical cavities, Num decreases with decreasing W . However in inclined ones, this trend is found only at lower Ra whereas at higher Ra , Num shows a maximum at about W = 0.5. Num also decreases when the number of partitions ( N p ) attached to the cold wall of the enclosure increases; however beyond a certain value of ( N p ), which depends of Ra , Num becomes almost constant.

Increased water shortages and new environmental policies and regulations have stimulated significant development in reuse programs in the past 20 years.1 Reclaimed water has been recognized as a vital and drought-proof water source to ensure economic and agricultural activities. According to the conclusions of various water reuse surveys, the best water reuse projects, in terms of economic viability and public acceptance, are those that substitute reclaimed water in lieu of potable water for use in industrial, irrigation, environmental restoration, cleaning and toilet flushing. The main benefits of using reclaimed water in these situations are conservation of water resources and pollution reduction. 1 Low Pressure Membranes (LPMs) such as Microfiltration (MF) and Ultrafiltration (UF) integrated with adsorption system could be a viable option for separation of contaminants in wastewater for reuse as boiler-feed or process water in industry. This article technically discusses the main constituents of concern in boiler-feed and process water requirements and finally suggests potentially efficient and low-energy-low-cost hybridized LPM /adsorption treatment facilities to achieve this paradigm shift towards new water sources.

In spite of the fact that commercial bromelain supplements are available in the market, to date, none of them are produced and formulated from recombinant forms. They are extracted and purified (often partially) from the stem and fruit of pineapple (Ananas comosus). This makes the production of bromelain very difficult, less reliable, often contaminated and expensive. In this study, a recombinant bromelain was expressed as soluble (active) and insoluble (inactive) enzyme in Escherichia coli BL21

International audience; A two-dimensional double Multiple Relaxation Time-Thermal Lattice Boltzmann Equation (2-MRT-TLBE) method is developed for predicting convective flows in a square differentially heated cavity filled with air (Pr=0.71). In this Letter, we propose a numerical scheme to solve the flow and the temperature fields using the MRT-D2Q9 model and the MRT-D2Q5 model, respectively. Thus, the main objective of this study is to show the effectiveness of such model to predict thermodynamics for heat transfer. This model is validated by the numerical simulations of the 2-D convective square cavity flow. Excellent agreements are obtained between numerical predictions. These results demonstrate the accuracy and the effectiveness of the proposed methodology.

International audience; The present paper deals with the numerical investigation of a 2D laminar fluid flow and heat transfer in a plane channel with two square blocks located at arbitrary positions. The numerical model is based on a coupling between the multiple relaxation time-lattice Boltzmann equation and the finite difference method for incompressible flow. Both the horizontal and the vertical separation distances between the two blocks are varied. Particular attention was paid to the distribution patterns of the time averaged local Nusselt number on the top and bottom walls. Results obtained from the present study show a complex flow patterns developed in the channel due to the change of the square blocks positions.

International audience; This article presents the application of the multiple-relaxation-time (MRT) lattice Boltzmann equation (LBE) method with nine-velocity model to the numerical prediction of a laminar and convective-heated transfer through a two-dimensional obstructed channel flow. The obstruction is carried out by three obstacles including two located on the upper wall and the other on the lower wall of the channel. The calculations are validated against results available in literature. Various physical arrangements are regarded as the size of the obstacles and the distance between the two upper obstacles to investigate their effects on thermal and flow characteristics. Results, presented for a Prandtl number equal to 0.71 and a Reynolds number ranging from 100 to 1200, showed that the heat transfer and the air flow depend both on the Reynolds number and geometric data of the configuration.

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PurposeThis paper attempts to deal with the presentation of a numerical investigation of the laminar‐free convective heat transfer in a square enclosure containing a solid cylinder located at an arbitrary position. Effects of the cylinder position on the heat transfer and the flow structures inside the cavity are to be studied and highlighted.Design/methodology/approachThe numerical code is based on the hybrid scheme with the lattice Boltzmann and the alternating‐directional implicit (ADI) splitting scheme. The energy equation is solved by ADI scheme and the flow field velocities have been computed using the lattice Boltzmann method (LBM). The bounce‐back condition combined with quadratic interpolation is used at solid boundaries.FindingsThe predicted results show that the cylinder location has a significant effect on the heat transfer. It is observed that: when the inner body does not generate heat, most of the heat transfer takes place if the body is located at the center of the enclosure. When the cylinder generates heat and is displaced from the left towards the right and from the lower part towards the upper part of the cavity, the heat transfer rate decreases on the hot wall and increases on the cold wall.Research limitations/implicationsThe fluid flow (air) is assumed to be incompressible, laminar and 2D. The viscous heat dissipation is neglected in the energy equation and all physical proprieties are constant except for the density, whose variation with temperature is allowed for in the buoyancy term.Practical implicationsNatural convection in heated enclosures, housing inner bodies has received significant attention because of its interest and importance in industrial applications. Some applications are solar collectors, fire research, electronic cooling, aeronautics, chemical apparatus, building constructions, nuclear engineering, etc.Originality/valueThe paper contributes to the development of the LBM. In particular, it was found that the inherent numerical instabilities of this LBE are not modified by coupling with temperature. This is a good improvement compared to what is observed in the simulations of thermal systems using the full LBE formulation where the energy conservation is taken into account.