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1.
PurposeThe purpose of the current framework is to scrutinize the two-dimensional flow and heat transfer of Casson nanofluid over cylinder/plate along with impacts of thermophoresis and Brownian motion effects. Also, the effects of exponential thermal sink/source, bioconvection, and motile microorganisms are taken.Methodology/ApproachThe resulting non-linear equations (PDEs) are reformed into nonlinear ODEs by using appropriate similarity variables. The resultant non-linear (ODEs) were numerically evaluated by the use of the Bvp4c package in the mathematical solver MATLAB.FindingsThe numerical and graphical illustration regarding outcomes represents the performance of flow-involved physical parameters on velocity, temperature, concentration, and microorganism profiles. Additionally, the skin friction coefficient, local Nusselt number, local Sherwood number, and local microorganism density number are computed numerically for the current presented system. We noted that the velocity profile diminishes for the rising estimations of magnetic and mixed convection parameters. The Prandtl number corresponds with the declining performance of the temperature profile observed. The enhancement in the values of the Solutal Biot number and Brownian motion parameter increased in the concentration profile.OriginalityIn specific, this framework focuses on the rising heat transfer of Casson nanofluid with bioconvection by using a shooting mathematical model. The novel approach of the presented study is the use of motile microorganisms with exponential thermal sink/source in a Casson nano-fluid through a cylinder/plate. A presented study performed first time in the author’s opinion. Understanding the flow characteristics and behaviors of these nanofluids is crucial for the scientific community in the developing subject of nanofluids.  相似文献   

2.

In this problem, examination of Casson nanofluid flow over nonlinear slanted extending sheet with chemical reaction and heat generation/absorption influences are under thought. Nanofluid exhibits in this examination is established on Buongiorno model. The governing nonlinear PDE’s are reduced to nonlinear ODE’s by employing suitable transformations. The Keller-box numerical technique is considered for simulation of this research. The influence of chemical reaction and nonlinear parameter on concentration and velocity distribution is analyzed. The recovered results exhibit that the impact of inclination and Casson factor reduced liquid velocity. While energy and mass transport rates are increased against inclination factor. Numerical and graphical outcomes are additionally exhibited in tables and graphs.

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3.
In this paper, the steady electrically conducting hybrid nanofluid (CuO-Cu/blood) laminar-mixed convection incompressible flow at the stagnation-point with viscous and gyrotactic microorganisms is considered. Additionally, hybrid nanofluid flow over a horizontal porous stretching sheet along with an induced magnetic field and external magnetic field effects that can be used in biomedical fields, such as in drug delivery and the flow dynamics of the microcirculatory system. This investigation can also deliver a perfect view about the mass and heat transfer behavior of blood flow in a circulatory system and various hyperthermia treatments such as the treatment of cancer. The simple partial differential equations (PDEs) are converted into a series of dimensional ordinary differential equations (ODEs), which are determined using appropriate similarities variables (HAM). The influence of the suction or injection parameter, mixed convection, Prandtl number, buoyancy ratio parameter, permeability parameter, magnetic parameter, reciprocal magnetic prandtl number, bioconvection Rayleigh number, coupled stress parameter, thermophoretic parameter, Schmidt number, inertial parameter, heat source parameter, and Brownian motion parameter on the concentration, motile microorganisms, velocity, and temperature is outlined, and we study the physical importance of the present problem graphically.  相似文献   

4.
Due to the illuminating function of nanoliquids in several technological and medicinal domains, particularly in liquid transport processes known as peristalsis, inquisitive researchers have investigated the flow of peristaltic nanofluids. Consequently, the current study investigates the entropy production and magnetic influence on the peristaltic transport of heat and mass transport of Casson nanofluid in a non-uniform channel under convective circumstances. Utilizing the perturbation approach, fields of concentration, temperature, and velocity are derived from non-linear coupled partial differential equations (PDE). Entropy generation studies have been done. In addition, the influence of associated factors via specific physical terms, including the Sherwood number, the skin-friction coefficient, and the Nusselt number, for both Casson and Newtonian liquids, as well as the trapping phenomena, is visually examined.  相似文献   

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6.
《印度化学会志》2023,100(2):100886
In this work, the statistical (“Numerical”) modelling of activation energy and chemical reaction on non-Newtonian liquid motion via stretching sheet (SS) were performed, analysed statistically, employing the shooting technique. The convective boundary conditions are considered on Casson liquid (“non-Newtonian”) motion with couple stress SS. The behaviour of thermophoresis diffusion and Brownian motion via a special effect of non-linear thermal radiation are assuming in temperature equation for liquid motion. This analysis highly governing nonlinear system of D. Es of velocity, temperature, concentration and activation are simulated via iterative scheme encoded with MATLAB programming language. The geometric model is described bvp 4th order of R-K-F (“Range-Kutta-Fehlberg”) scheme. We found that, 35% of heat transfer rate produces in motion of couple stress Casson nanofluid and the activation energy released 28% of mass transfer rate at stretching surface. A comparative result of linear and nonlinear SS presented via various dimensionless parameters on graphs and tables.  相似文献   

7.

This study aimed to investigate the increase in heat transfer in the indirect heater at a city gate station (CGS) with the addition of copper oxide (CuO) nanoparticles to water–ethylene glycol base fluids. Indirect heaters are typically used at CGSs to raise the heat transfer coefficient of output gas flow from ? 5 to 15 °C. Moreover, manufacturing laboratory equipment in the presence of water–ethylene glycol base fluid and the nanoparticle in volume fractions of 0.05, 0.1, 0.2, and 0.3 at a temperature of 40–70 °C was discussed using dimensional simulation and analysis. The physical properties of the base fluid and nanofluid were measured using precise devices. Heat transfer tests for the base and nanofluid, as well as replacing of the air by gas, were conducted in a simulated and developed device. According to the obtained results with respect to the changes in convection and conduction heat transfer, enhancement of temperature difference at a rate of 36% was observed in the indirect heater with nanoparticle volume concentration of 0.2% at a temperature of 70 °C. Moreover, the Nusselt number showed a relatively good agreement with theoretical discussions.

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8.
A numerical simulation model for laminar flow of nanofluids in a pipe with constant heat flux at the wall has been built to study the effect of Reynolds number on heat transfer and pressure loss. The investigation was performed for metallic oxide and multi-oxide nanoparticles suspended in water. The thermal conductivity and dynamic viscosity were measured for a range of temperature (10–60 °C) and volume fraction of multi-oxide nanofluid. Comparison of the thermal conductivity for monocular oxide and multi-oxide nanofluids reveals a new way to control the enhancement in nanofluid conductivity. The numerical results obtained were compared with existing well-established correlations. The predictions of the Nusselt number for nanofluids are in agreement with the Shah correlation, and the deviation in the results is less than 1 %. It is found that the pressure loss increases with the Reynolds number, nanoparticle density, and volume fraction for multi-oxide nanoparticles. However, the flow demonstrates enhancement in heat transfer which improves with increasing Reynolds number of the flow.  相似文献   

9.

Nonlinear mixed convection of heat and mass in a stagnation-point flow of an impinging jet over a solid cylinder embedded in a porous medium is investigated by applying a similarity technique. The problem involves a heterogenous chemical reaction on the surface of the cylinder and nonlinear heat generation in the porous solid. The conducted analysis considers combined heat and mass transfer through inclusions of Soret and Dufour effects and predicts the velocity, temperature and concentration fields as well as the average Nusselt and Sherwood number. It is found that intensification of the nonlinear convection results in development of higher axial velocities over the cylinder and reduces the thickness of thermal and concentration boundary layers. Hence, consideration of nonlinear convection can lead to prediction of higher Nusselt and Sherwood numbers. Further, the investigation reveals that the porous system deviates from local thermal equilibrium at higher Reynolds numbers and mixed convection parameter.

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10.

The object of this study is to analyze the impact of heterogeneous and homogeneous reactions on the flow, heat and mass transfer analysis of Maxwell nanofluid of Tiwari–Das kind over a stretched cylinder by considering convective boundary condition and velocity slip. Ethylene glycol (Eg) is used as base fluid; while gold (Au) and silver (Ag) are taken as nanoparticles. The governing equations represent nanofluid momentum, and energy and mass are reduced to system of nonlinear ordinary differential equations by utilizing similarity transformation procedure and are numerically evaluated by using finite element method. The sway of several pertinent parameters on the sketches of velocity, temperature and concentration is plotted through graphs. In addition to that the values of rate of heat transfer and skin-friction coefficient are calculated and presented through tables. The values of skin-friction coefficient are intensified as the values of homogeneous–heterogeneous reaction parameters rises. The velocity and concentration scatterings are both declines as the strength of Maxwell parameter raises.

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11.
《印度化学会志》2022,99(12):100782
Nanofluids have a vital role in many industries due to their novelty of heat transfer. Various mathematical techniques are required to simulate such problems. It can seem that traditional partial differential equations are incapable of analyzing and investigating the physical behavior of flow parameters affected by memory effects. This research communicates the implementation of the most interesting analytical method namely Prabhakar fractional derivative regarding the thermal flow of Casson fluid with single and multiwall carbon-nanotubes due to an inclined plate. The water and blood are considered as base particles. slip and Newtonian heating impacts for the thermal flow are also considered. The fractional modal of leading PDE's is attained by Prabhakar fractional derivative with various limiting cases. The generalized solution for the thermal and velocity field is simulated via the Laplace transformation method. The thermal expressions are modeled via Fourier expressions. Graphs are used to illustrate the influence and behaviour of key physical and fractional characteristics. The finding is that the temperature and velocity profiles of SWCNTs are more prominent than those of MWCNTs. Changing the fractional parameter values results in a greater rise in the velocity gradient for blood-based nanofluid than for water-based nanofluid.  相似文献   

12.

A numerical analysis was carried out of mixed convection heat transfer for a laminar flow in a rectangular inclined microchannel totally filled with a water/Al2O3 nanofluid. The governing conservation equations are translated into a dimensionless form using the thermal single relaxation time and they modify the lattice Boltzmann method with double distribution functions. The viscous dissipation effects are adapted to the energy equation. The effects of nanoparticle volume fractions ? (0?≤???≤?0.04) and inclination angles γ (0°?≤?γ?≤?60°) on the flow of the nanofluid and the heat transfer are investigated. The obtained results are presented in terms of streamlines, isotherms, slip velocity, wall temperature and Nusselt number. The results show that the higher values of the volume fraction of Al2O3 and the large values of inclination angles improve the heat transfer rate.

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13.

In this numerical study, laminar flow of water nanofluid/GNP–SDBS (graphene nanoplatelet–sodium dodecylbenzene sulfonate) for 0–0.1% solid nanoparticles mass fraction was investigated for Reynolds numbers of 50–1000 in 3D space via finite volume method. In the newly proposed microchannel design, the cooling fluid is moving in countercurrent in the upper and lower layers of the microchannels, and there are cavities and sinusoidal routes on the solid walls of the microchannel, and the presence of rectangular ribs on the flow centerline along the fluid path enhances mixing for cooling fluid and creates better heat transfer for warm surfaces. The results of this study show that this special design of the microchannel can have a substantial increase in Nusselt number and heat transfer so that in the considered geometry by adding solid nanoparticles mass fraction it is possible to increase average Nusselt number for each Reynolds number by approximately 20%. Also, the mixing of the fluid because of formation of secondary flows has a strong effect on making the temperature distribution uniform in the cooling fluid and solid bed (wall) of the microchannel, especially in the lower layer. The upper layer of the microchannel always has a lower temperature due to indirect contact with heat flux compared with the lower layer. In this study, by increasing Reynolds number and mass fraction of solid nanoparticles the Nusselt number is increased and heat resistance of the lower wall of the microchannel is reduced. Based on the investigation of flow field and heat transfer, the use of the proposed design of the microchannel is recommended for Reynolds number less than 300.

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14.
《印度化学会志》2021,98(11):100200
For the first time, the heat transfer performance of a CuO–ZnO (80:20)/water hybrid has been studied experimentally and numerically in a shell and tube heat exchanger under turbulent flow conditions nanofluid (STHE). All experiments are carried out with 0.01 ​vol% CuO–ZnO (80:20)/water hybrid nanofluid at Reynolds numbers (NRe) ranging from 1900 to 17,500. The stabilized hybrid nanofluids (30 ​°C-Tube side) are then used as a coolant to reduce the hot fluid (60 ​°C-shell side) temperature using a STHE, with the results for the convective heat transfer coefficient, Nusselt number, friction factor, and pressure drop reported. The primary goal of this paper is to investigate the impact of hybrid nanoparticle mixing ratio optimization on STHE heat transfer efficiency under various operating conditions. According to the findings, the CuO–ZnO (80:20)/water hybrid nanofluid improved the heat transfer performance of the STHE at all Reynolds numbers. When using nanofluid over water, the Nusselt number and pressure drop were improved by approximately 33% and 13%, respectively. The hybrid nanofluid's maximum thermal performance factor and thermal efficiency enhancement were 1.45 and 7%, respectively, at NRe ​= ​17,500. According to the study, the thermal conductivity of nanofluid varies by only 5% after ten trials. Furthermore, the ANSYS Fluent program was used to predict the behavior of the hybrid nanofluid in STHE, and the simulation results fit the experimental values very well.  相似文献   

15.

The lattice Boltzmann method is used to study natural convection of a CuO/water nanofluid in a hollow cavity. The hollow walls are fixed at a uniform temperature, and the effect of an applied magnetic field is examined. The Koo–Kleinstreuer–Li model, which accounts for nanoparticle’s Brownian motion, is used to gain the nanofluid effective thermal conductivity and nanofluid viscosity. The mechanisms how the inclination angle of magnetic field, Hartmann number, Rayleigh number, hollow width and nanoparticle volume fraction affect the streamlines, isotherms and rate of heat transfer are also studied. The results show that the average Nusselt number is increased by incrementing the nanoparticle volume fraction, Ra, magnetic field inclination angle and hollow width, but decreased by the Ha. For L = 0.4, the value of Ra where the dominant mechanism of heat transfer is changed from conduction to convection is larger than 105. But for L = 0.48 or 0.56, the turning point of the dominant heat transfer mechanism is at Ra < 105. Besides, at L = 0.4 or 0.48, the average Nusselt numbers in hot walls are higher than those in cold wall, but the opposite trend is found at L = 0.56.

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16.

Turbulent flow characteristics and heat transfer applications of a twisted heat exchanger with 3-lobed cross section along with Y-tape insert are numerically studied. The working fluids for the simulations are pure water and water–Al2O3 nanofluid using two-phase mixture model. The study is carried out for various nanofluid volume fractions of 0.01, 0.02 and 0.03 with Reynolds number in the range of 5000–20,000. The effect of nanoparticles in heat transfer augmentation for smooth and lobed tubes is discussed based on presenting the highest thermal performance, which is a relation between heat transfer rate and pressure loss. Results show that implementing the twisted tube with Y-tape insert enhances the heat transfer more than the twisted tube. Relative Nusselt numbers for twisted tubes decrease with Reynolds number in comparison with the plain tube. Turbulent intensity, swirl number and tangential velocity of twisted tube with insert are higher than empty twisted tube indicating that inserting the Y-tape intensifies the turbulence and disturbs the fluid flow further. On the other hand, although the twisted tube increases the pressure drop more than plain tube, the case with Y-tape drastically increases the friction factor. So, the thermal performance of twisted tube with insert is lower than empty twisted tube. Adding nanoparticles to the base fluid has different influence on the investigated cases. It augments the relative Nusselt number inside plain tube and empty twisted tube with slight increment in friction factor. Increasing the nanoparticles concentration enhances the heat transfer rates for these cases while it does not increase the relative Nusselt number inside twisted tube with Y-tape insert at high Reynolds number and nanoparticle concentration. Moreover, it can be found that twisted tube with or without Y-tape insert is more efficient at low Reynolds number in comparison with the plain tube.

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17.

In this paper, we analyze the effect of heat transfer on the flow of tangent hyperbolic nanofluid in a ciliated tube (fallopian tube where embryo in blood make the development). This study will be beneficial for the researchers and medical experts in the field of embryology. The nanoparticles are beneficial to remove the cysts from the fallopian tube where development of embryo takes place. To resolves the ciliary flow problems, medical doctors use nanoparticles (drug delivery) that may create a temperature gradient. The heat transfer helps to optimize the energy for which the entropy generation is reduced. Therefore, in this research we discuss the heat transfer effect on tangent hyperbolic nanofluid and entropy generation due to ciliary movement. The governing partial differential equations are solved by HPM and software MATHEMATICA?. Effect of viscoelastic parameter, nanoparticles, cilia length and Brinkman number on the velocity, temperature and entropy generation has been illustrated with the help of graphs. Graphical results show that thermal conductivity of fluid increases by adding nanoparticles. The entropy generation due to nanoparticles will decrease the viscosity near the tube wall and blood through tube will flow with normal pressure.

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18.

In the present paper, the effect of nanofluid and the hot obstacle in a Π-shaped cavity is investigated. Lattice Boltzmann method is used to simulate the fluid flow and heat transfer. The effects of the parameters such as the nanoparticle solid volume fraction, the Rayleigh number, aspect ratio of cavity and hot obstacle position on the flow pattern and heat transfer parameters are studied. The numerical results are compared with previous results for validation, and a good agreement obtained. It is found that the average Nusselt number is increased by increasing the nanoparticle solid volume fraction, the Rayleigh number and the aspect ratio of cavity. Moreover, the effect of Rayleigh number on the average Nusselt number at high Rayleigh numbers (105–106) is more pronounced than that at low Rayleigh numbers (103–104) due to the different heat transfer mechanisms. The position of the hot obstacle affects the heat transfer significantly. When the hot obstacle is located on the center, the heat transfer is more effective.

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19.
This study is to investigate the magnetohydrodynamic (MHD) stagnation point flow and heat transfer characteristic nanofluid of carbon nanotube (CNTs) over the shrinking surface with heat sink effects. Similarity equations deduced from momentum and energy equation of partial differential equations are solved numerically. This study looks at the different parameters of the flow and heat transfer using first phase model which is Tiwari-Das. The parameter discussed were volume fraction nanoparticle, magnetic parameter, heat sink/source parameters, and a different type of nanofluid and based fluids. Present results revealed that the rate of nanofluid (SWCNT/kerosene) in terms of flow and heat transfer is better than (MWCNT/kerosene) and (CNT/water) and regular fluid (water). Graphically, the variation results of dual solution exist for shrinking parameter in range λc<λ1 for different values of volume fraction nanoparticle, magnetic, heat sink parameters, and a different type of nanofluid. However, a unique solution exists at 1<λ<1, and no solutions exist at λ<λc which is a critical value. In addition, the local Nusselt number decreases with increasing volume fraction nanoparticle when there exists a heat sink effect. The values of the skin friction coefficient and local Nusselt number increase for both solutions with the increase in magnetic parameter. In this study, the investigation on the flow and heat transfer of MHD stagnation point nanofluid through a shrinking surface with heat sink effect shows how important the application to industrial applications.  相似文献   

20.
Journal of Thermal Analysis and Calorimetry - In the present paper, a numerical study on flow and heat transfer of air/nanofluid impinging jet flow through a cylindrical porous heat sink has been...  相似文献   

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