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Showing papers on "Reynolds number published in 2022"


Journal ArticleDOI
TL;DR: In this article , the behavior of the human cardiovascular system is characterized by the Casson fluid model while the physical properties of iron (Fe3O4) and copper (Cu) are used in the analysis.
Abstract: Curved veins and arteries make up the human cardiovascular system, and the peristalsis process underlies the blood flowing in these ducts. The blood flow in the presence of hybrid nanoparticles through a tapered complex wavy curved channel is numerically investigated. The behavior of the blood is characterized by the Casson fluid model while the physical properties of iron (Fe3O4) and copper (Cu) are used in the analysis. The fundamental laws of mass, momentum and energy give rise the system of nonlinear coupled partial differential equations which are normalized using the variables, and the resulting set of governing relations are simplified in view of a smaller Reynolds model approach. The numerical simulations are performed using the computational software Mathematica’s built-in ND scheme. It is noted that the velocity of the blood is abated by the nanoparticles’ concentration and assisted in the non-uniform channel core. Furthermore, the nanoparticles’ volume fraction and the dimensionless curvature of the channel reduce the temperature profile.

89 citations


Journal ArticleDOI
TL;DR: In this article , a hybrid nano-powders, fin and helical tape was used to increase the efficiency of the absorber unit by increasing the pitch factor and diameter of circular gaps.

67 citations


Journal ArticleDOI
TL;DR: In this paper , physics-informed neural networks (PINNs) are applied for solving the Navier-Stokes equations for laminar flows by solving the Falkner-Skan boundary layer.
Abstract: Physics-informed neural networks (PINNs) are successful machine-learning methods for the solution and identification of partial differential equations. We employ PINNs for solving the Reynolds-averaged Navier–Stokes equations for incompressible turbulent flows without any specific model or assumption for turbulence and by taking only the data on the domain boundaries. We first show the applicability of PINNs for solving the Navier–Stokes equations for laminar flows by solving the Falkner–Skan boundary layer. We then apply PINNs for the simulation of four turbulent-flow cases, i.e., zero-pressure-gradient boundary layer, adverse-pressure-gradient boundary layer, and turbulent flows over a NACA4412 airfoil and the periodic hill. Our results show the excellent applicability of PINNs for laminar flows with strong pressure gradients, where predictions with less than 1% error can be obtained. For turbulent flows, we also obtain very good accuracy on simulation results even for the Reynolds-stress components.

47 citations


Journal ArticleDOI
TL;DR: In this paper, the authors analyzed the flow around the cylinder in the tube-row channel heat exchanger through numerical simulation, and they showed that the use of TiO2-H2O nanofluids can improve the comprehensive performance of heat exchange.

43 citations


Journal ArticleDOI
TL;DR: In this paper , the cooling system of a two-dimensional lithium-ion battery pack with 9 battery cells is simulated and the amount of pressure drop and temperature of cooling system is assessed.
Abstract: In this paper, the cooling system of a two-dimensional lithium-ion battery pack with 9 battery cells is simulated. The airflow at the Reynolds number range from 80 to 140 flows through the cooling system. In this analysis, the temperature of all 9 battery cells is examined separately. The amount of pressure drop and temperature of the cooling system is assessed. Another geometry variable is the size of the inlets and outlets, which are changed simultaneously between 0.1 and 0.2. The finite element method is used for the simulations. The findings suggest that increasing the Reynolds number lowers the battery pack's maximum temperature. At a Reynolds number of 80, increasing the input temperature raises the maximum temperature of all the battery cells except the one in the battery. In model 6, this increase has increased the maximum temperature by more than 40%. Increasing the intake size raises the maximum temperature of all battery cells at other Reynolds numbers. The battery cell located at the inlet has the minimum, and the battery cell located at the outlet side has the maximum temperature. An enhancement in the Reynolds number and inlet size intensifies the pressure drop in the cooling system.

43 citations


Journal ArticleDOI
Pata, Kai1
TL;DR: In this paper , the effects of using magnetic field and packed bed phase change material (PCM) system in a 3D cavity having ventilation ports on the performance improvements are analyzed during hybrid nanoliquid convection.

41 citations


Journal ArticleDOI
TL;DR: In this paper , the authors analyzed the flow and heat transfer characteristics of tube-row channel heat exchangers with different types and structural parameters, and found that the adjustment of the number of ribs, the height of ribs and the ratio of transverse pitch diameter can increase Nusselt numbers by 53.63%, 57.25%, 52.38% and 12.93% at maximum.

40 citations


Journal ArticleDOI
TL;DR: In this paper , a shell and tube heat exchanger with non-continuous helical baffles (NCHB-STHX) is modeled numerically and the ratio of heat transfer coefficient to pressure drop (HTC/ΔP) is obtained from different angles and intensities.

40 citations


Journal ArticleDOI
TL;DR: In this paper , the mass load ratio has a significant impact on droplet transport characteristics of gas-liquid two-phase jets, and the equilibrium position of droplet breakup and coalescence is calculated and found to be quite close to the nozzle exit.

34 citations


Journal ArticleDOI
TL;DR: In this paper , the flow of non-Newtonian blood fluid with nanoparticles inside a vessel with a porous wall in presence of a magnetic field was investigated and the results showed that increasing the Gr number, porosity and negative pressure increase the blood velocity and increasing the magnetic field intensity decrease the blood velocities.
Abstract: In this paper, the flow of non-Newtonian blood fluid with nanoparticles inside a vessel with a porous wall in presence of a magnetic field have been investigated. This study aimed to investigate various parameters such as magnetic field and porosity on velocity, temperature, and concentration profiles. In this research, three different models (Vogel, Reynolds and Constant) for viscosity have been used as an innovation. The governing equations are solved by Akbari-Ganji's Method (AGM) analytical method and the Finite Element Method (FEM) is used to better represent the phenomena in the vessel. The results show that increasing the Gr number, porosity and negative pressure increase the blood velocity and increasing the magnetic field intensity decrease the blood velocity.

34 citations


Journal ArticleDOI
TL;DR: In this paper , the authors explored thermal performance features for a coupled conjugate thermo-fluid system with different cooling configurations (flat channel (F-C), grooved channel (G-C) and impinging jets (I-J)) by using non-Newtonian nanofluid.

Journal ArticleDOI
TL;DR: In this article , the authors considered the dynamics of water conveying multi-walled carbon nanoparticles (MWCNT) through a vertical Cleveland Z-staggered cavity where entropy generation plays a significant role.
Abstract: To date, when considering the dynamics of water conveying multi-walled carbon nanoparticles (MWCNT) through a vertical Cleveland Z-staggered cavity where entropy generation plays a significant role, nothing is known about the increasing Reynold number, Hartmann number, and Darcy number when constant conduction occurs at both sides, but at different temperatures. The system-governing equations were solved using suitable models and the Galerkin Finite Element Method (GFEM). Based on the outcome of the simulation, it is worth noting that increasing the Reynold number causes the inertial force to be enhanced. The velocity of incompressible Darcy-Forchheimer flow at the middle vertical Cleveland Z-staggered cavity declines with a higher Reynold number. Enhancement in the Hartman number causes the velocity at the center of the vertical Cleveland Z-staggered cavity to be reduced due to the associated Lorentz force, which is absent when Ha = 0 and highly significant when Ha = 30. As the Reynold number grows, the Bejan number declines at various levels of the Hartmann number, but increases at multiple levels of the Darcy number.


Journal ArticleDOI
TL;DR: In this paper , direct numerical simulations are performed to investigate the spatial evolution of flat-plate zero-pressure-gradient turbulent boundary layers over long streamwise domains, with the surface temperatures ranging from quasiadiabatic to highly cooled conditions.
Abstract: Abstract Direct numerical simulations (DNS) are performed to investigate the spatial evolution of flat-plate zero-pressure-gradient turbulent boundary layers over long streamwise domains (${>}300\delta _i$, with $\delta _i$ the inflow boundary-layer thickness) at three different Mach numbers, $2.5$, $4.9$ and $10.9$, with the surface temperatures ranging from quasiadiabatic to highly cooled conditions. The settlement of turbulence statistics into a fully developed equilibrium state of the turbulent boundary layer has been carefully monitored, either based on the satisfaction of the von Kármán integral equation or by comparing runs with different inflow turbulence generation techniques. The generated DNS database is used to characterize the streamwise evolution of multiple important variables in the high-Mach-number, cold-wall regime, including the skin friction, the Reynolds analogy factor, the shape factor, the Reynolds stresses, and the fluctuating wall quantities. The data confirm the validity of many classic and newer compressibility transformations at moderately high Reynolds numbers (up to friction Reynolds number $Re_\tau \approx 1200$) and show that, with proper scaling, the sizes of the near-wall streaks and superstructures are insensitive to the Mach number and wall cooling conditions. The strong wall cooling in the hypersonic cold-wall case is found to cause a significant increase in the size of the near-wall turbulence eddies (relative to the boundary-layer thickness), which leads to a reduced-scale separation between the large and small turbulence scales, and in turn to a lack of an outer peak in the spanwise spectra of the streamwise velocity in the logarithmic region.

Journal ArticleDOI
TL;DR: In this article , a micro-channel heat sink (MCHS) with micro-pin-fins was investigated numerically, and optimal configurations were obtained in terms of Reynolds number and porosity.

Journal ArticleDOI
TL;DR: In this article, the effect of magnetic field intensity on velocity and temperature distributions has been presented with contour graphs and the results showed that Nusselt number increases with increasing Reynolds number and decreasing pitch ratio.

Journal ArticleDOI
TL;DR: In this article , the effect of magnetic field intensity on velocity and temperature distributions has been presented with contour graphs and the simulations have been built up by Realizable k-ε turbulence model and single-phase approach.

Journal ArticleDOI
TL;DR: In this article , the effect of pipeline surface roughness on impact forces on suspended and laid-on-seabed pipelines caused by mudflows is quantified. And a standard chart methodology considering pipeline roughness to estimate peak impact forces is established, which provides a basis for the risk assessment of the whole life cycle of submarine pipelines.

Journal ArticleDOI
TL;DR: In this article , the effect of forced cooling enhancements such as baffles and fins on the performance of the 150 W solar photovoltaic thermal collectors (PV/T) was investigated.

Journal ArticleDOI
TL;DR: In this article, a three-dimensional fluid-solid conjugate model with symmetric and parallel wavy microchannels was studied, and the results showed that the symmetric configuration yields higher Nusselt numbers than the parallel one, and it is especially true for higher Reynolds numbers and larger amplitude-to-wavelength ratios.

Journal ArticleDOI
TL;DR: In this article , the effects of temperature on hydrodynamic cavitating flows in a Venturi section are investigated to find the optimum reacting conditions enhancing cavitating treatment intensity. But the authors focus on the phase transition of the cavitation length and thickness.

Journal ArticleDOI
TL;DR: In this article, the effect of particle wake on the heat transfer characteristics between interactive particles in supercritical water is simulated and analyzed, and the main influencing factors include particle distance, Reynolds number (Re), particle temperature and pressure.


Journal ArticleDOI
TL;DR: In this article , an evacuated absorber tube with glass cover, non-uniform heat flux, and taking into account the convective and radiative heat losses was analyzed for parabolic trough collectors.

Journal ArticleDOI
TL;DR: In this paper, the effects of using convergent, convergent-divergent and divergent conical wire coils in ethylene glycol and water mixture flow region on the augmentation of heat transfer are experimentally analyzed.

Journal ArticleDOI
TL;DR: In this article , the performance of a flat plate solar collector operating under thermosyphon conditions using MWCNT + Fe 3 O 4 /Water hybrid nanofluids was investigated.

Journal ArticleDOI
TL;DR: In this paper , the charging performance of a small-scale cuboid-shaped ice container unit with two rows of serpentine tubes equipped with connecting plates has been numerically examined, and the charging process was monitored using a dimensionless parameter, named, stored energy ratio which considers both sensible and latent energy storage progress.
Abstract: Each year around 1.3 billion tons of food is wasted in the world. Some of this food waste is due to the improper performance of the cold chain, which can be controlled by the means of cold thermal energy storage devices. In this research, the charging performance of a small-scale cuboid-shaped ice container unit with two rows of serpentine tubes equipped with connecting plates has been numerically examined. The container is designed to be utilized as a cooling backup for home refrigeration units in developing countries to compensate for the heat load during the frequent power outages in these regions and to help food preservation during these times. The impacts of various dimensionless parameters regarding the flow and geometric aspects of the serpentine tubes and extended surfaces have been examined in this ice container. These parameters were the Reynolds and modified Stefan numbers of the refrigerant flow, serpentine tube pitch length/container height ratio (γ1), the serpentine tube row distance/container width ratio (γ2), the serpentine tube diameter/container diagonal length ratio (γ3), the plate area/the maximum plate area ratio (γ4), and the plate thickness/tube diameter ratio (γ5). The charging process was monitored using a dimensionless parameter, named, stored energy ratio which considers both sensible and latent energy storage progress. The results suggest that higher γ1, γ2, γ4, and γ5, and lower γ3 values lead to enhanced charging rates. It was also found that installing the full-coverage thick plates (γ4 = 1 and γ5 = 0.0081) increases the time-averaged charging rate by 18%.

Journal ArticleDOI
TL;DR: In this paper , the authors investigated the effects of temperature on hydrodynamic cavitating flows and found the optimum reaction conditions for enhancing cavitating treatment intensity, including cavitation number σ, Reynolds number Re and thermodynamic parameter Σ.

Journal ArticleDOI
TL;DR: In this paper , an instantaneous streamwise velocity perturbation of a new simulation of a turbulent channel flow at an unprecedented friction Reynolds number of 10000 was conducted, solving some questions and raising new ones.
Abstract: An instantaneous streamwise velocity perturbation of a new simulation of a turbulent channel flow at an unprecedented friction Reynolds number of 10000 is conducted. One point statistics and turbulent budgets are discussed, solving some questions and raising new ones.

Journal ArticleDOI
TL;DR: In this article , the influence of various types of parameters such as Brownian motion, thermophoresis, buoyancy forces, and magnetic fields are studies on concentration, temperature, and axial velocity.
Abstract: The significance of the study is to determine of transferred heat and mass impact on the magneto-hydrodynamic peristalsis of Jeffery nanofluid through porous media with inclined symmetric channels whose walls are induced by peristaltic motion within porous media. The aim of this investagtion is to study the influence of various types of parameters such as Brownian motion, thermophoresis, buoyancy forces, and magnetic fields are studies on concentration, temperature, and axial velocity. The numerical solution has been achieved according to the long-wavelength and low Reynolds number approximation utilizing the MATLAB bvp4c function. The resultant dimensions of nonlinear governing equations were approached numerically through the Runge-Kutta- Fehlberg integration scheme, a MATLAB program. The influence of different factors such as the ratio of relaxation to retardation times, nanoparticle Grashof number, and magnetic field was discussed on concentration, temperature, and velocity profiles. tables and graphs were used to demonstrate the numerically computed numerical results. Plotting graphs were utilized for evaluating the pertinent parameters impacts on the aforementioned quantities based on computational results. According to the findings, the effect of the parameters are significant.