Subjects -> CHEMISTRY (Total: 928 journals)     - ANALYTICAL CHEMISTRY (59 journals)    - CHEMISTRY (661 journals)    - CRYSTALLOGRAPHY (23 journals)    - ELECTROCHEMISTRY (28 journals)    - INORGANIC CHEMISTRY (45 journals)    - ORGANIC CHEMISTRY (47 journals)    - PHYSICAL CHEMISTRY (65 journals) PHYSICAL CHEMISTRY (65 journals)
 Showing 1 - 64 of 64 Journals sorted alphabetically ACS Central Science       (Followers: 9) ACS Physical Chemistry Au       (Followers: 7) ACS Sensors       (Followers: 7) Acta Physico-Chimica Sinica Advances in Image and Video Processing       (Followers: 20) Advances in Physical Chemistry       (Followers: 13) Annual Review of Physical Chemistry       (Followers: 14) Applied Materials Today       (Followers: 1) Biophysical Chemistry       (Followers: 8) Catalysis, Structure & Reactivity       (Followers: 2) Chemical Physics       (Followers: 18) Chemical Physics Letters       (Followers: 17) Chemistry and Physics of Lipids       (Followers: 2) Chinese Journal of Chemical Physics       (Followers: 1) Colloids and Surfaces A: Physicochemical and Engineering Aspects       (Followers: 6) Current Physical Chemistry       (Followers: 1) Doklady Physical Chemistry EPJ B - Condensed Matter and Complex Systems       (Followers: 1) EPJ E - Soft Matter and Biological Physics       (Followers: 3) Friction       (Followers: 4) Geochemistry, Geophysics, Geosystems       (Followers: 35) Glass Physics and Chemistry       (Followers: 1) Handbook on the Physics and Chemistry of Rare Earths       (Followers: 2) Indian Journal of Biochemistry and Biophysics (IJBB)       (Followers: 3) Indian Journal of Chemistry - Section A       (Followers: 9) International Journal of Polymeric Materials       (Followers: 6) International Journal of Quantum Chemistry       (Followers: 5) International Reviews in Physical Chemistry       (Followers: 3) Journal of Biophysical Chemistry       (Followers: 3) Journal of Chemical Physics       (Followers: 36) Journal of Chromatographic Science       (Followers: 15) Journal of Macromolecular Science, Part B: Physics       (Followers: 2) Journal of Physical and Chemical Reference Data       (Followers: 4) Journal of Physical Chemistry A       (Followers: 28) Journal of Physical Chemistry B       (Followers: 48) Journal of Physical Chemistry C       (Followers: 36) Journal of Physical Chemistry Letters       (Followers: 26) Journal of Physics and Chemistry of Solids       (Followers: 3) Journal of Quantum Chemistry       (Followers: 1) Journal of Radiation Research       (Followers: 3) Macromolecular Chemistry and Physics       (Followers: 2) Molecular Physics: An International Journal in the Field of Chemical Physics       (Followers: 24) Nature Communications       (Followers: 323) Open Journal of Physical Chemistry Physical Chemistry       (Followers: 2) Physical Chemistry Chemical Physics       (Followers: 29) Physical Chemistry Research       (Followers: 1) Physical Review A       (Followers: 23) Physical Review Accelerators and Beams       (Followers: 3) Physical Review B       (Followers: 33) Physical Review D       (Followers: 11) Physical Review E       (Followers: 41) Physical Review Letters       (Followers: 133) Physics and Chemistry of Glasses - European Journal of Glass Science and Technology Part B Physics and Chemistry of Liquids: An International Journal Physics and Chemistry of the Earth, Parts A/B/C       (Followers: 10) Plasma Processes and Polymers       (Followers: 2) Protection of Metals and Physical Chemistry of Surfaces       (Followers: 15) Revista Fuentes Russian Journal of Physical Chemistry A, Focus on Chemistry Russian Journal of Physical Chemistry B, Focus on Physics Solid State Ionics       (Followers: 5) The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics       (Followers: 29) The European Physical Journal Special Topics       (Followers: 1)
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 The European Physical Journal Special TopicsJournal Prestige (SJR): 0.552 Citation Impact (citeScore): 2Number of Followers: 1      Hybrid journal (It can contain Open Access articles) ISSN (Print) 1951-6355 - ISSN (Online) 1951-6401 Published by Springer-Verlag  [2469 journals]
• A rigorous multi-population multi-lane hybrid traffic model for
dissipation of waves via autonomous vehicles

Abstract: Abstract In this paper, a multi-lane multi-population microscopic model, which presents stop-and-go waves, is proposed to simulate traffic on a ring-road. Vehicles are divided between human-driven and autonomous vehicles (AV). Control strategies are designed with the ultimate goal of using a small number of AVs (less than 5% penetration rate) to represent Lagrangian control actuators that can smooth the multilane traffic flow and dissipate the traffic instabilities, and in particular stop-and-go waves. This in turn may reduce fuel consumption and emissions. The lane-changing mechanism is based on three components that we treat as parameters in the model: safety, incentive and cool-down time. The choice of these parameters in the lane-change mechanism is critical to modeling traffic accurately, because different parameter values can lead to drastically different traffic behaviors. In particular, the number of lane-changes and the speed variance are highly affected by the choice of parameters. Despite this modeling issue, when using sufficiently simple and robust controllers for AVs, the stabilization of uniform flow steady state is effective for any realistic value of the parameters, and ultimately bypasses the observed modeling issue. Our approach is based on accurate and rigorous mathematical models. The interest, among others, is that such mathematical model has been shown to allow a limit procedure that is termed, in gas dynamic terminology, mean-field. In simple words, from increasing the human-driven population to infinity, a system of coupled ordinary and partial differential equations are obtained. Finally, we explore collaborative driving by assuming that a fraction of human drivers is instructed to drive smoothly to stabilize traffic. We show that this approach also leads to dissipation of waves.
PubDate: 2022-05-23

• Magneto-convective flow through a porous enclosure with Hall current and

Abstract: Abstract This paper reports the numerical study of magnetohydrodynamic radiative-convective flow in a square cavity containing a porous medium with Hall currents. This study is relent to hydromagnetic fuel cell design and thermofluidic dynamics of complex magnetic liquid fabrication in enclosures. The governing equations of this fluid system are solved by a finite-difference vorticity stream function approach executed in MATLAB software. A detailed parametric investigation of the impact of Rayleigh number (thermal buoyancy parameter), Hartman number (magnetic body force parameter), Darcy number (permeability parameter), Hall parameter and radiation parameter on the streamline, temperature contours, local Nusselt number along the hot wall and mid-section velocity profiles is computed. Validation with previous special cases in the literature is included. Hall current and radiative effects are found to significantly modify thermofluidic characteristics. From the numerical results, it is found that the magnetic field suppresses the natural convection only for small buoyancy ratios. But, for larger buoyancy ratio, the magnetic field is effective in suppressing the thermal convective flow.
PubDate: 2022-05-23

• Jet impingement cooling using shear thinning nanofluid under the combined
effects of inclined separated partition at the inlet and magnetic field

Abstract: Abstract Combined effects of using inclined partition and magnetic field on the cooling performance of double slot jet impingement are analyzed with finite element method. Two different shear thinning nanofluids are used while experimental data is available for the rheological properties. Different values of of Reynolds number (Re between 100 and 1000), velocity ratio (VR, between 0.2 and 1), opening ratio (OR, between 0.05 and 0.95), magnetic field strength (Ha, between 0 and 30) and inclination of partition ( $$\Omega$$ , between 0 and 40) are used. It is observed that varying VR of the jets, size/inclination of the partition, magnetic field strength and nanfluid type, can be used to control the local and average convective heat transfer and cooling performance features effectively. The average Nusselt number (Nu) rises with higher VR while at the highest VR the amount of increments are 23.5 $$\%$$ and 28.5 $$\%$$ with first (NF1) and second (NF2) nanofluid (NF). When magnetic field is imposed, effects of OR becomes important with NF1 at the lowest strength of magnetic field. Average Nu reduces with higher magnetic field strength for NF1 while $$14.4\%$$ reduction for the highest strength at OR = 0.95 is achieved. However, for NF2 the trend is opposite and $$18.8\%$$ increment is obtained. Variations in the average Nu becomes $$7.6\%$$ and $$1.8\%$$ for NF1 and NF2 when inclination of the partition is changed. The cooling performance is estimated by using a feed-forward network modeling approach in terms of average Nu for NF1 and NF2 by using 25 neuron in the hidden layer.
PubDate: 2022-05-21

• The effect of fins and wavy geometry on natural convection heat transfer
of $$\hbox {TiO}_{{2}}$$ TiO 2 –water nanofluid in trash bin-shaped
cavity

Abstract: Abstract This paper studies the effect of fins number and size and wavy wall of a trash bin-shaped cavity on the natural convection heat transfer (NC) of a $$\hbox {TiO}_{2}$$ –water nanofluid. The flow is considered buoyancy driven, which is under thermal radiation. The effects of Rayleigh number ( $$10^{3}-10^{5})$$ , thermal radiation (0.1 $$-$$ 0.3), nanoparticle concentration (0.02 $$-$$ 0.04), and geometry are investigated. Non-dimensional mode of NS equations would be governing equations, and the finite element technique is utilized to discrete them. Two plans are examined: firstly, the effects of thermal parameters on the enclosure with no fin are studied. Secondly, the effects of the fins length and number, and also the wavy geometry on Nusselt number (Nu) and flow distribution are investigated. The findings of the present paper are that increasing the fin number around the inner cylinder increases $$\hbox {Nu}_{\mathrm{avg}}$$ up to 54%, and reduces the local entropy generation (EG) and enhances the Bejan number. Moreover, if the wavy wall amplitude changes from 0.05 to 0.1, $$\hbox {Nu}_{\mathrm{avg}}$$ reduces by 31%, and if the Ra changes from $$10^{3}$$ to $$10^{5}$$ , $$\hbox {Nu}_{\mathrm{avg}}$$ increases up to 36%.
PubDate: 2022-05-20

• Taguchi optimization of automotive radiator cooling with nanofluids

Abstract: Abstract Considering the influences of the heat transfer rate in automotive radiators on several aspects such as engine performance, fuel economy and available space for components, the present study numerically investigates the impacts of different nanofluids on the heat transfer and pressure drop in an automotive radiator. Four different parameters each having four levels are taken into consideration, which are nanoparticle volume fraction ( $$\phi =0.1, 0.3, 0.7$$ , and 1%), Reynolds number (Re $$=$$ 9350, 13,800, 18,500 and 23,000), type of base fluid (EG20, EG40, EG60, and water) and type of nanoparticle ( $$\hbox {Fe}_{3}\hbox {O}_{4}$$ , CuO, $$\hbox {Al}_{2}\hbox {O}_{3}$$ , and $$\hbox {SiO}_{2})$$ . Taguchi method is employed for reducing the number of parameter combinations from 256 to 16. It is found that the nanofluid utilization improves heat transfer between 3.2 and 45.9% depending on the combination of the investigated parameters. Pressure drop is noticeably increased due to nanofluid utilization. Regarding the Taguchi optimization, using $$\hbox {Fe}_{3}\hbox {O}_{4}$$ –water nanofluid with 0.3% volume fraction at Re $$=$$ 9350 is the most appropriate option for a high heat transfer with relatively low pressure drop. It is concluded that the radiator size can be reduced by 10.8% by using nanofluids due to the improvement in heat transfer, which consequently allow a larger space to designers for placing other components.
PubDate: 2022-05-20

• Double diffusive convective transport and entropy generation in an annular
space filled with alumina-water nanoliquid

Abstract: Abstract Many of the engineering/industrial applications involving the energy transport undergoes entropy generation which is unavoidable and this leads to degradation of system efficiency. Several researchers working in this field are exploring new ways to minimize the entropy generation so that the efficiency of the system could be enhanced. Motivated by these applications, the current article scrutinizes the rate of entropy generation along with thermal and solutal transport resulting from double-diffusive convective phenomenon in a nanoliquid-filled annular enclosure. Along vertical surfaces of the annulus, the uniform temperature and concentration conditions are specified, while the upper and lower boundaries are maintained as insulated and impermeable. The set of non-linear coupled governing equations in vorticity-stream function form supported by related initial and boundary conditions are computed numerically using time-splitting technique. The influence of various controlling parameters namely the buoyancy ratio ( $$-5 \le N \le 5$$ ), Lewis number ( $$0.5\le {Le} \le 2$$ ), aspect ratio ( $$0.5\le {Ar} \le 2$$ ) and nanoparticle volume fraction ( $$0\le \phi \le 0.05$$ ) on fluid movement, temperature, concentration and entropy production are scrutinized and variation in thermal and solutal dissipation rates, entropy production and Bejan number are graphically illustrated and are discussed with physical interpretation. Through the vast range of computational experiments, it has been found that the quantity of generated entropy in an enclosure is greater during aided flow compared to that of opposing case. Further, it has also been found that higher thermal and solutal performance rates with minimal loss of system energy (entropy generation) could be achieved with a shallow annulus.
PubDate: 2022-05-19

• Coupled buoyancy and Marangoni convection in a hybrid nanofluid-filled
cylindrical porous annulus with a circular thin baffle

Abstract: Abstract The purpose of the current article is to evaluate the impact of coupled buoyancy and thermocapillary driven convection in a cylindrical porous annulus saturated with Ag/MgO–water hybrid nanofluid along with viscous dissipation effects. The left side wall of the annulus is kept heated, while the right side wall of the annulus is kept cold. The top and bottom limits are supposed to be adiabatic. A thin circular baffle is anchored to the inner cylinder. The primary goal of this research is to look into the effect of baffle size and location on Marangoni convection, thermal behaviour, and flow fields. Here, the effects of viscous dissipation are taken into account. The governing equations are subjected to the finite difference approach, which employs the ADI, SOR, and central differencing schemes. In this work, contour plots and average Nusselt number profiles are used to demonstrate the flow type, temperature behaviour, and thermal variations along the enclosure. The research demonstrates that the size and location of the fin plays a prominent role in influencing fluid flow within the annulus. An improvement in thermal transfer rate is reported for $$\phi$$ and for the higher value of Ma considering the viscous dissipation, length and location of the baffle.
PubDate: 2022-05-19

• OpenFOAM for computational combustion dynamics

Abstract: Abstract In computational fluid dynamics (CFD), the mathematical description of a physical phenomenon that involves fluid flow, combustion, and chemical reaction is combined with a numerical solution of the problem via the use of a computer process. Computational fluid dynamics has emerged as a critical tool for comprehending and forecasting the behavior of reacting flows, which are fundamentally complicated systems involving the intricate interplay of chemical kinetics and fluid mechanics. Among the numerous open source CFD packages, the widely used C++ finite volume simulation toolbox OpenFOAM (Open-Source Field Operation and Manipulation) has a number of advantages, including an object-oriented framework, the ease with which multiphysics modules can be added, and its free availability. However, numerous shortcomings have been identified regarding its application to chemically reacting flows, most notably incomplete splitting schemes, inadequate ordinary differential equation (ODE) solvers for stiff chemistry, and oversimplified mixture transients. This article focuses on the combustion flow in an intake manifold. A sample intake manifold consists of two inlets and one outlet. The finite volume method is used for computing the mathematical modeling developed for combustion. The focus of the attention will be the demonstration of the structure of the flame. The energy deposition and pressure near the outlet are higher. The results are compared and found a good agreement between OpenFOAM and DUNE (Distributed and Unified Numerics Environment) numerics.
PubDate: 2022-05-19

• Mixed convection in a double lid-driven rectangular cavity filled with
hybrid nanofluid subjected to non-uniform heating using finite-volume
method

Abstract: Abstract Mixed convection in a rectangular double lid-driven cavity filled with hybrid nanofluid (Al $$_2$$ O $$_3$$ –Cu–water) subjected to insulated sidewalls and sinusoidal temperature on horizontal walls is numerically investigated. Using the SIMPLE algorithm for pressure, velocity coupling, the momentum, mass conservation, and energy equations are numerically solved by the finite-volume method (FVM). The data were validated by comparing the present results with the results of the problem solved by Sarris et al. (Numer Heat Transf Part A Appl 42(5):513–530, 2010) for pure liquid. The effects of amplitude ratio, phase deviation, and Reynolds numbers on the flow and heat transfer characteristics are discussed. It is found that the rate of heat transfer is improved as the volume fraction of the hybrid nanoparticles and the amplitude ratio are increased. The non-uniform heating at cavity walls tend to provide higher heat transfer rate and the heat transfer rate increases with respect to Reynolds number.
PubDate: 2022-05-18

• Computational analysis of fluid immersed active cooling for battery
thermal management using thermal lattice Boltzmann method

Abstract: Abstract A computational analysis of the thermal management system of a battery-pack, whereby the cells are actively cooled at their surfaces by being immersed in a nanofluid medium. Nanofluids used in the automotive and energy management systems are selected and modelled within this work. The present study is conducted by carefully observing the flow structures, thermal energy distribution, entropy generation and pumping power requirements within the battery-pack, to be able to present a resource helpful for designers in the preliminary stages of their thermal management system. This study throws light beyond the case of the battery-pack thermal management, to other applications that require to be maintained at a given temperature or require a certain quantity of heat to be removed from it.
PubDate: 2022-05-18

• Numerical simulation of non-uniform heating due to magnetohydrodynamic
natural convection in a nanofluid filled rhombic enclosure

Abstract: Abstract Numerical simulation of magnetohydrodynamic natural convection heat transfer in a rhombic enclosure of inclination angle $${\mathrm {45}}^{\mathrm {^{\circ }}}$$ containing copper-water nanofluid has been presented in this paper. The top and bottom walls of the enclosure are subjected to non-uniform heating while left wall being subjected to lower temperature and right wall being maintained adiabatic. The finite element strategy (COMSOL Multiphysics) is used to solve the governing equations. The numerical simulations are done for the parametric values: 10 $$^{4\, }\le$$ Rayleigh number $$\le$$ 10 $$^{6}$$ ; 0 $$\le$$ Hartmann number $$\le$$ 100; 0 $$\le$$ volume fraction of nanofluid $$\le$$ 0.05. The phase deviation angle (top wall) is varied in the range from 0 to $${\uppi }$$ with amplitude of non linear heating being maintained constant. The motivation of this research goes with the fact that the associated transport phenomenon conveys the implication of designing an optimal thermal system analogous to the theme of non-uniform heating, with the phase angle being a crucial design parameter. The numerical results depict to the fact, that the rate of heat transfer follows non-monotonic trends and is considerably influenced by interplay of the phase shift angle, Rayleigh number and Hartmann number. The results showed that at Rayleigh number $$\ge 10^{5}$$ , the heat transfer rate gets inhibited by enhancing the magnetic field intensity. The impact of different types of nano particles is illustrated by comparing the results with the results of three different nanofluids, silver– water, titanium dioxide–water and diamond–water nanofluids.
PubDate: 2022-05-18

• Magneto-hydrothermal performance of hybrid nanofluid flow through a
non-Darcian porous complex wavy enclosure

Abstract: Abstract The present work elucidates the hydrothermal characteristics within a non-Darcian porous complex wavy enclosure saturated with $$\hbox {Al}_{2}\hbox {O}_{3}$$ –Cu– $$\hbox {H}_{2}\hbox {O}$$ hybrid nanofluid considering a uniform magnetic field. The left sidewall of the enclosure is wavy and heated isothermally, whereas the other sidewall is maintained at ambient temperature, all other walls are insulated. The Forchheimer–Brinkman-extended Darcy model is implemented to analyze the flow through porous media. The dimensionless transport equations are numerically solved following the finite volume-based in-house computational code with successive staggered non-uniform mesh distribution. The hydrothermal behaviors are investigated meticulously changing the dimensionless variables like undulation amplitude ( $$\lambda$$ ), Hartmann number (Ha), Darcy number (Da), and modified-Rayleigh number ( $$\hbox {Ra}_{\mathrm{m}}$$ ). The remarkable results reveal that enhancing the heating surface area by heightening the amplitude of the undulation always leads to higher heat transfer, but does not always favor the growth of the flow strength. The heightening of the flow strength with amplitude is noted for higher $$\hbox {Ra}_{\mathrm{m}}$$ only. The flow intensity, as well as heat transfer, increases with the growing $$\hbox {Ra}_{\mathrm{m}}$$ . The same decreases with increasing Da and Ha. Local distribution of heat transfer characteristics shows complex behavior depending on the amplitude of the undulations and associated dimensionless numbers.
PubDate: 2022-05-17

• CBS-FEM algorithm for mixed convection of irregular-shaped porous
lid-driven cavity utilizing thermal non-equilibrium medium

Abstract: Abstract This contribution examines a highly forced convection situation due to the movements of two adjacent wavy and straight walls of two-sided wavy enclosures. An adiabatic obstacle is located within the domain and the top boundary is partially heated. The included porous medium is assumed to be radiant and the two-energy equations system is applied for this proposed. An inclined magnetic force together with heat generation sources is inclusive in the flow area. The governing equations have been solved utilizing the characteristic-based split algorithm under the spirit of finite-element method. Numerical outcomes for the flow and heat transfer for the fluid and solid phases are determined for miscellaneous combinations of the physical factors. Graphical and tabular findings pointing out interesting features of the physics of the problem are presented and discussed. The forced convection mode is dominant at higher values of the undulation parameter $$\lambda$$ and low values of $$\mathrm {the\, Hartmann\, \, number}$$ Ha. Also, the radiative porous medium reduces the Nusselt coefficient for the solid phase. Furthermore, the rate of the heat transfer is reduced by 80% when the values of the Darcy coefficient are decreased from $${10}^{-2}$$ to $${10}^{-5}$$ .
PubDate: 2022-05-17

• Thermal treatment inside a partially heated triangular cavity filled with
casson fluid with an inner cylindrical obstacle via FEM approach

Abstract: Abstract A comprehensive numerical study is presented for the hydromagnetic flow and heat transfer of Casson fluid in an enclosed partially heated triangular cavity. A cylindrical obstacle is placed with different thermal boundary conditions inside the cavity. The governing partial differential equations are converted to a non-dimensional form via suitable similarity variables. Well-known finite element method (FEM) is employed to solve the governing equations and investigate the impact of various physical parameters like the length of the heating element, Casson and radiation parameters, and the Hartmann number on the streamlines, isotherms, and local Nusselt numbers. Simulations are performed for the three selected (cold, adiabatic, and heated) conditions of an inner cylindrical obstacle. It is demonstrated that the maximum Nusselt number ensues near the edges of the heating element and the Casson parameter tends to reduce the Nusselt number. It is also found that the length of the heating element has substantial effects on the heat transfer in the cavity. The new results of this study may help to study the thermal control and non-Newtonian fluids inside closed enclosures.
PubDate: 2022-05-17

• Complex urban systems: a living lab to understand urban processes and
solve complex urban problems

PubDate: 2022-05-16

• Effect of double rotating cylinders on the MHD mixed convection and
entropy generation of a 3D cubic enclosure filled by nano-PCM

Abstract: Abstract In this manuscript, phase change material (PCM) including the nanoparticles is considered in a 3D cubic enclosure to investigate the mixed convection of heat transfer under the magnetic field effect. Double rotating cylinders also are located in the middle of the enclosure to study the effect of their angular velocity in different conditions. Governing equations are solved by Galerkin Finite Element Method (GFEM) and were confirmed by previous studies. As main outcomes, results with enhanced angular velocity, both the average temperature and cumulative energy were significantly decreased. Furthermore, unaltered fluidity ( $$\hbox {Ha}=0$$ ) imposes greater entropy, but this tendency reverses when the Hartman number (Ha) rises, resulting in minimum entropy trends.
PubDate: 2022-05-16

• Natural convection investigation under influence of internal bodies within
a nanofluid-filled square cavity

Abstract: Abstract The current article presents a numerical simulation of the nanofluid convection inside a square enclosure with two inner adiabatic circular bodies. Galerkin finite-element analysis was utilized to solve the governing equations under the assumptions of laminar, steady flow conditions considering a homogeneous single-phase approach. The parameters under investigation are Rayleigh number (Ra), solid volume fraction, the horizontal position of the two inner cylinders, and the inclination angle of the enclosure. The results indicate that increasing the Rayleigh number, and the solid volume fraction improves the heat transport rate. It is obtained that at low Ra, there is no significant impact on the enclosure angle, while as the Ra goes up, the heat transfer rate increases gradually. In addition, the best location of the internal bodies is in the middle of the cavity as it exhibits an increase in the flow velocity. To obtain the highest Nusselt number, it is recommended to use an inclination angle of 30 at any value of the Rayleigh number.
PubDate: 2022-05-16

• Numerical investigation of unsteady MHD mixed convective flow of hybrid
nanofluid in a corrugated trapezoidal cavity with internal rotating
heat-generating solid cylinder

Abstract: Abstract This study examines the magnetohydrodynamic flow of hybrid silver-alumina (Ag-Al $$_2$$ O $$_3$$ )/water nanofluid within a corrugated trapezoidal cavity that contains a heat-generating rotating solid cylinder. The hybrid nanofluid flow and convective heat transfer are modelled using a single-phase approach. The governing equations for fluid flow and convective heat transfer are solved using the penalty finite element method. The finite element algorithm was validated against previously published work, and it was found to be in good agreement with the existing literature. We investigate the effects of the Ag and Al $$_2$$ O $$_3$$ nanoparticle diameters and the radius of the heat-generating solid cylinder on streamlines, isotherms and average Nusselt number. The results of this study reveal that the flow circulation regions near the rotating cylinder are enhanced with increased nanoparticle diameters and cylinder radius. Moreover, the nanofluid temperature and heat transfer rate are increased with reduced nanoparticle diameters and increased cylinder radius.
PubDate: 2022-05-15

• Temporal instability of nanofluid layer in a circular cylindrical cavity

Abstract: Abstract The instability of an interface formed at the boundary of a circular cylindrical cavity is examined through an irrotational theory of viscous fluids. The cavity is assumed to be an infinite circular cylinder and the flow is considered to be two-dimensional. The cavity is filled with the Newtonian viscous fluid while the fluid outside the cavity is taken as Newtonian nanofluid. The normal mode procedure is employed and the growth rate parameter is calculated. The quadratic relationship in growth rate is achieved and for larger modes, it reduces to the case of the planar interface. The variety of nanofluids’ physical parameters is studied on the instability of the interface. The density of nanofluid makes the interface more unstable while nanofluid’s viscosity has stabilizing nature. The nanofluid with larger radius nanoparticles forms a more unstable interface than the smaller sized nanoparticles.
PubDate: 2022-05-15

• Natural convection of hybrid nanofluid flow in the presence of multiple
vertical partial magnetic fields in a trapezoidal shaped cavity

Abstract: Abstract In this paper, a numerical investigation on natural convection flow of silver(Ag)-magnesium oxide(MgO)-water hybrid nanofluid in a trapezoidal shaped cavity under the effect of partial magnetic fields is carried out. Unsteady, dimensionless governing equations in stream function-vorticity formulation are approximated by radial basis functions (Rbfs) in space and the fourth order backward differentiation formula in time. Pseudo time derivative in stream function equation is also taken into account. Brinkman model for dynamic viscosity and Xue’s model for thermal conductivity are adopted. The pertinent observed parameters are Rayleigh number ( $$10^4 \le Ra \le 10^6$$ ), Hartmann numbers ( $$0\le Ha_1, Ha_2 \le 100$$ ), equally weighted concentration of nanoparticles ( $$0 \le \phi _1, \phi _2 \le 0.01$$ ), tilt angle of oblique walls ( $$0 \le \theta \le \pi /9$$ ) and the lengths of the partial magnetic fields ( $$0.5 \le \ell _{b_1}, \ell _{b_2} \le 1$$ ). The large area of impact region of partial magnetic field results in inhibition of fluid flow and heat transfer.
PubDate: 2022-05-14

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