Comparative Study of Reversal Flow during the Evaporation or Condensation of Water and Ethanol Film in a Vertical Channel

A comparative study of reversal flow is carried out to investigate the effect of thermal and mass buoyancy forces with evaporation or condensation along a vertical channel. The highlight is focused on the effects of phase change of two different liquid films having widely different properties, on heat and mass transfer rates in the channel. The evaporation occurs along isothermal and wetted walls. The induced laminar upward flow consists of a mixture of blowing air and vapour of water or ethanol. Various combinations of thermal and solutal boundary conditions (cooling and heating modes) are considered to investigate extensively their influence on the flow development. A two-dimensional steady state and elliptical flow model is used and the liquid film is assumed extremely thin. The governing equations of the model are solved by FVM and the velocity-pressure fields are treated with the SIMPLER algorithm. The results show that the buoyancy forces have a significant effect on the hydrodynamic, thermal and mass fields of both gas mixtures. In addition, the flow reversal is predicted with a relatively high temperature difference between the air-mixture and the wetted walls

Numerical Predictions Using LBM Application: Laminar Mixed Convection of Non-Newtonian Nanofluids in Ventilated Square Cavities

In this paper, we investigate numerically the flow field and heat transfer of a viscoplastic nanofluid flowing within ventilated devices. The incompressible nanofluid with constant and uniform physical and rheological properties is composed of silver nanoparticles suspended in a non-Newtonian base fluid that obeys the Bingham rheological model. This numerical study is based on the multiple relaxation-time Lattice Boltzmann method (MRT-LBM). The two-dimensional nine velocities (D2Q9) model is adopted to solve the flow field, while the two-dimensional five-velocity (D2Q5) model is developed to solve the temperature field. The impact of various pertinent parameters, such as Richardson (0.01 ≤ Ri ≤ 100), Bingham (0 ≤ Bn ≤ 20), and Prandtl numbers (1 ≤ Pr ≤ 30), is widely inspected, side by side with the nanoparticles volume fraction (0 ≤ j ≤ 10%). The obtained results show the important effect of these parameters, which cannot be neglected, on both flow and heat transfer structures, in this type of cavities

Progress on numerical simulation of nanofluids: impact of an isothermal spherical partition on the mixed convection of nanofluids within cubic enclosures

The main objective of our work is to light out the three-dimensional flow of an Ag-water nanofluid within a lid-driven cubical space which equipped with a spherical heater into its center. Due to its crucial role in the characterization of the main transfer within such configurations, impact of some parameters is widely inspected. It consists the Richardson value (0,05 to 50), the solid volume fraction (0% to 10%), as well as the heater geometry (10% ≤ d ≤ 25%). To do so, a numerical code based on the Lattice-Boltzmann method, coupled with a finite difference one, is used. The latter has been validated after comparison between the present results and those of the literature. It is to note that the three dimensions D3Q19 model is adopted based on a cubic Lattice, where each pattern of the latter is characterized by nineteen discrete speeds

Three dimensional fluid flow within a rectangular channel with several cylindrical (and/or) elliptical blocks: lattice boltzmann investigation

Through this paper, we investigate numerically a Three-dimensional laminar flow of an incompressible Newtonian fluid within a rectangular channel; including several adiabatic partitions of a cylindrical (and/or) elliptical shape. To do so, a numerical code based on the Lattice Boltzmann approach is used. In other words, three dimensions D3Q19 model is adopted all based on a cubic Lattice, where each pattern of the latter is characterized by nineteen discrete speeds. Our numerical code has been successfully validated after a wide comparison between the present results and those of the literature. By taking into account the Reynolds number, the partitions’ shape impact on the flow fields within the channel is taking all attention and that throughout the time’ Streamlines and the velocity profiles. The pressure drop within our channel is also investigated to come out with the best arrangement of these kinds of partitions within

Progress on numerical simulation of nanofluids: impact of an isothermal spherical partition on the mixed convection of nanofluids within cubic enclosures

The main objective of our work is to light out the three-dimensional flow of an Ag-water nanofluid within a lid-driven cubical space which equipped with a spherical heater into its center. Due to its crucial role in the characterization of the main transfer within such configurations, impact of some parameters is widely inspected. It consists the Richardson value (0,05 to 50), the solid volume fraction (0% to 10%), as well as the heater geometry (10% ≤ d ≤ 25%). To do so, a numerical code based on the Lattice-Boltzmann method, coupled with a finite difference one, is used. The latter has been validated after comparison between the present results and those of the literature. It is to note that the three dimensions D3Q19 model is adopted based on a cubic Lattice, where each pattern of the latter is characterized by nineteen discrete speeds

Three-dimensional numerical study of mixed convection within a ventilated cavity (Shape ‘ L ‘) crossed by a nanofluid under the effect of a magnetic field

The present work is dedicated to the three-dimensional numerical study of mixed convection heat transfer, taking place within a ventilated cavity (of shape L) crossed by Cu-water nanofluid. The enclosure is subjected to the action of a magnetic field. The ventilation is assured by two openings of the same size. The cold flow enters by an opening practiced at the top of the left wall, and exits by another opening practiced at the bottom of the right vertical wall. All the cavity walls are maintained at the same temperature, superior to that of the entering flow, except the side walls which are considered as adiabatic. The control parameters are: the Reynolds number and the Hartmann number as well as the nanoparticles volume fraction

Three-dimensional numerical study of mixed convection within a ventilated cavity (Shape ‘ L ‘) crossed by a nanofluid under the effect of a magnetic field

The present work is dedicated to the three-dimensional numerical study of mixed convection heat transfer, taking place within a ventilated cavity (of shape L) crossed by Cu-water nanofluid. The enclosure is subjected to the action of a magnetic field. The ventilation is assured by two openings of the same size. The cold flow enters by an opening practiced at the top of the left wall, and exits by another opening practiced at the bottom of the right vertical wall. All the cavity walls are maintained at the same temperature, superior to that of the entering flow, except the side walls which are considered as adiabatic. The control parameters are: the Reynolds number and the Hartmann number as well as the nanoparticles volume fraction

Three dimensional fluid flow within a rectangular channel with several cylindrical (and/or) elliptical blocks: lattice boltzmann investigation

Through this paper, we investigate numerically a Three-dimensional laminar flow of an incompressible Newtonian fluid within a rectangular channel; including several adiabatic partitions of a cylindrical (and/or) elliptical shape. To do so, a numerical code based on the Lattice Boltzmann approach is used. In other words, three dimensions D3Q19 model is adopted all based on a cubic Lattice, where each pattern of the latter is characterized by nineteen discrete speeds. Our numerical code has been successfully validated after a wide comparison between the present results and those of the literature. By taking into account the Reynolds number, the partitions’ shape impact on the flow fields within the channel is taking all attention and that throughout the time’ Streamlines and the velocity profiles. The pressure drop within our channel is also investigated to come out with the best arrangement of these kinds of partitions within