Heat Transfer Of non-Newtonian Fluid Research Articles

Role of polymers in managing flow and heat transfer in non-Newtonian fluids

This research article delves into the crucial role that polymers play in controlling the boundary layer flow and heat transfer of non-Newtonian fluids past a stretching surface. To explore the various behaviors of non-Newtonian fluid flow, two classical viscosity models—Reiner–Philippoff and Powell–Eyring—are utilized. Taking into account the microstructure and concentration of polymers, a molecular approach is employed to describe the viscoelasticity effect. Through numerical similarity analysis, the impact of polymers on flow and heat transfer control of non-Newtonian fluids is examined in detail. The article also discusses the behavior of skin friction and the Nusselt number in the presence of polymers. It is observed that the viscosity of the fluid decreases in the vicinity of the surface as the polymers interact with velocity gradients in the boundary layer. However, as the distance from the surface increases, the viscosity returns to its original value. Moreover, the addition of polymers within the non-Newtonian fluid leads to a reduction in heat transport and an enhancement in skin drag. Overall, this study sheds light on the crucial role of polymers in optimizing heat transfer and controlling flow behavior in non-Newtonian fluids.

Study on Phase Change Flow and Heat Transfer Characteristics of Microalgae Slurry in the Absorber Tube of a Parabolic trough Solar Collector

The study of gas–liquid two-phase flow and heat transfer in non-Newtonian fluids is of great significance for the research and development of refrigeration and energy storage. In this paper, the characteristics and influencing factors of the phase change reaction in microalgae slurry were studied by numerical simulation and experimental verification. In order to further study the rheological and heat transfer characteristics of gas–liquid two-phase flow in the collector, the effects of wall heat flux, inlet velocity and microalgae slurry concentration on the phase change reaction in microalgae slurry were studied. The results show that when the boundary conditions of microalgae slurry with the same concentration change, the phase transition of microalgae slurry is different. The higher the wall heat flux, the more forward the phase transition occurs, and the smaller the flow rate, the more forward the phase transition occurs. When the boundary conditions remain unchanged, the phase transition point of microalgae slurry with different concentrations is the same, and the concentration of microalgae slurry will not be affected. However, the deviation between the fluid temperature and the thermal conductivity of high-concentration fluid after phase change is larger than that of low-concentration fluids. The deviation in the fluid temperature reaches approximately 10 K, and the deviation in thermal conductivity reaches approximately 0.025 W/(m·K). Therefore, the change in the fluid temperature and heat transfer intensity after phase change in microalgae slurry is more intense than that of Newtonian fluids.

Thermal analysis of Non-Newtonian visco-inelastic fluid MHD flow between rotating disks

Analytical techniques are used in this article to examine the forced flow and heat transfer in a non-Newtonian Reiner-Rivlin fluid between two infinitely revolving disks in a magnetic field. The partial differential equations (PDEs) emphasizing flow and heat transfer were transformed into a nonlinear ordinary differential equations (ODEs) system using the Von Karman similarity transformation. The system of nonlinear ODEs with boundary conditions was solved using the Homotopy Perturbation Method (HPM) and Akbari-Ganji's Method (AGM). The study assessed the effects of physical factors on temperature profiles and the radial, transverse, and axial velocity components, including the visco-inelastic parameter, Reynolds number, Prandtl number, forced parameter, and magnetic field. The Python programming language was used for symbolic and numeric calculations of velocity components and temperature profiles. The accuracy of the results obtained through the analytical approach validates the applicability and efficiency of the proposed approach for studying the forced flow and heat transfer in non-Newtonian fluids between rotating disks.

Study of nonlinear radiative heat transfer with magnetic field for non-Newtonian Casson fluid flow in a porous medium

This paper studies the effect of thermo-diffusion, electrical field, and nonlinear thermal radiation. Thermal radiant heat transfer has several industrial applications, and the analysis of radiation heat transfer in non-Newtonian fluids under different conditions has been widely studied. To better understand the problem of thermal nonlinear radiation heat transfer flow in non-Darcy Casson fluid on stretched surfaces, this research examines such a phenomenon. The Hybrid Analytical and Numerical Method (The HAN Method) is used to precisely analyze the steady flow of incompressible Newtonian electrically conducting non-Darcy Casson fluid on a vertical permeable stretchable plate with the presence of the magnetic field. The governing equations of this problem are reduced from the system of nonlinear partial differential equations (PDEs) into a system of nonlinear ordinary differential equations (ODEs) using similarity transformations. The results showed that Casson's parameter has a small and indirect effect on temperature and mass transfer, but it affects the velocity significantly and directly. Also, the magnetic field has a direct and significant effect on temperature and velocity but an indirect and significant effect on concentration. The electric field has a direct and significant effect on temperature and velocity but an indirect and significant effect on concentration. Also, the effects of parameters such as thermal buoyancy, inertial, porous permeability, Eckert number, Prandtl number, chemical reaction, Schmidt and Soret numbers, and porosity on velocity, temperature, and concentration have been studied.

Investigation of non-Newtonian power-law free convection affected by a magnetic field in an inclined quarter-circle chamber containing the lozenge-shaped obstacle via MRT-LBM of first and second laws of thermodynamics

Investigating the effect of the strength, type and angle of the magnetic field applied on the amount of entropy generation caused by the heat transfer of non-Newtonian fluid under the inflyence of heat production/absorption is the aim of the available study. The simulation has been done by writing the FORTRAN code using Multi relaxation time lattice Boltzmann method. Qualitative and quantitative comparison of the present work with preceding valid researches confirmed the accurateness of the outcomes. The magnetic field influence can be controlled by the angle of rotation of the chamber, and this impact decreases with power-law index enhancement. In general, application of a non-uniform magnetic field increases the mean Nusselt number by about 10% and leads to an increase in flow strength. The outcomes reveal that the impact of the angle of inclination chamber, type and direction of magnetic field application for dilatant fluid is insignificant. Increasing the coefficient of the heat absorption/production lessens the mean Nusselt number but increases the impact of the magnetic field. Enhancement of the barrier temperature and decreasing index of power-law results in an increment in the share of entropy generated by the magnetic field.

Rheological synergistic thermal conductivity of HEC-based silicon dioxide nanofluids in shear flow fields

The classical constitutive equations for heat transfer of non-Newtonian fluids in shear flow fields neglect viscous dissipation and the field synergistic properties of rheology and heat transfer. In this paper, a novel constitutive Eq. (6) for rheological synergy thermal conductivity was derived by considering viscous dissipation. Based on this, we established an experimental platform to investigate the heat transfer properties of HEC-based silicon dioxide nanofluids (different nanoparticle sizes and volume fractions) in shear flow field for two cases: neglecting viscous dissipation and considering viscous dissipation. The results show that viscous dissipation have very important effects on heat transfer behavior at different shear rates and rheological properties. The contribution of viscous dissipation to the thermal conductivity increases with shear rate and particle volume fraction, but decreases with temperature. Among all the measured results, the maximum contribution of viscous dissipation to the thermal conductivity reached 19.86%. This confirms that the viscous dissipation is not negligible and the field synergy between rheology and heat transfer of non-Newtonian fluids must be considered in the shear flow fields.

Numerical analysis of flow and forced convection heat transfer of non-Newtonian fluid in a pipe based on fractional constitutive model

PurposeThis paper aims to use a fractional constitutive model with a nonlocal velocity gradient for replacing the nonlinear constitutive model to characterize its complex rheological behavior, where non-linear characteristics exist, for example, the inherent viscous behavior of the crude oil. The feasibility and flexibility of the fractional model are tested via a case study of non-Newtonian fluid. The finite element method is non-Newtonian used to numerically solve both momentum equation and energy equation to describe the fluid flow and convection heat transfer process.Design/methodology/approachThis paper provides a comprehensive theoretical and numerical study of flow and heat transfer of non-Newtonian fluids in a pipe based on the fractional constitutive model. Contrary to fractional order a, the rheological property of non-Newtonian fluid changes from shear-thinning to shear-thickening with the increase of power-law index n, therefore the flow and heat transfer are hindered to some extent.FindingsThis paper discusses two dimensionless parameters on flow regime and thermal patterns, including Reynolds number (Re) and Nusselt number (Nu) in evaluating the flow rate and heat transfer rate. Analysis results show that the viscosity of the non-Newtonian fluid decreases with the rheological index (order α) increasing. While large fractional (order α) corresponds to the enhancement of heat transfer capacity.Research limitations/implicationsFirst, it is observed that the increase of the Re results in an increase of the local Nusselt number (Nul). It means the heat transfer enhancement ratio increases with Re. Meanwhile, the increasement of the Nul indicating the enhancement in the heat transfer coefficient, produces a higher speed flow of crude oil.Originality/valueThis study presents a new numerical investigation on characteristics of steady-state pipe flow and forced convection heat transfer by using a fractional constitutive model. The influences of various non-dimensional characteristic parameters of fluid on the velocity and temperature fields are analyzed in detail.

Impact of pseudoplaticity and dilatancy of fluid on peristaltic flow and heat transfer: Reiner-Philippoff fluid model

The objective of this article is to investigate the impact of pseudoplaticity and dilatancy of fluid on peristaltic flow and heat transfer of non-Newtonian fluid in a non-uniform asymmetric channel. The mathematical-model incorporates the non-linear implicit stress deformation relation using the classical Reiner-Philippoff viscosity model, which is one of the very few non-Newtonian models exhibiting all the pseudoplastic, dilatant and Newtonian behaviors. The governing equations for the peristaltic flow and heat transfer of Reiner-Philippoff fluid are modeled using the low Reynolds-number and long wavelength approximation. Results of the study are presented graphically to discuss the impact of pseudoplaticity and dilatancy of fluid on the velocity, pressure gradient, bolus movement and temperature profile. The article is concluded with key observations that by increasing the value of the Reiner-Philippoff fluid parameter the velocity of fluid increase at the center of the channel and decreases near the boundaries of the channel. Effects of the shear stress parameter are opposite on pseudoplastic and dilatants fluid. By increasing the value of the shear stress parameter the velocity of the pseudoplastic fluid increases near the center of the channel, whereas the velocity of dilatants fluid decreases.

Free convective heat transfer of a non-Newtonian fluid in a cavity containing a thin flexible heater plate: an Eulerian–Lagrangian approach

In the present study, the free convection heat transfer of a power-law non-Newtonian fluid is considered in a cavity containing a flexible hot thin heater. The sidewalls of the square cavity are maintained at cold temperatures, while the hot heater is placed inside the cavity. The top and bottom walls of the cavity are kept insulated. The thin heater plate can undergo large deformations due to the interaction between the fluid flow and the heater. The arbitrary Lagrangian–Eulerian moving mesh method is employed to track the displacement of the heater in the fluid domain. Appropriate non-dimensional parameters are utilized to transform the governing equations into a general non-dimensional form. The equations governing fluid flow and heat transfer are solved using the finite element method with an automatic time-stepping scheme. The effect of control parameters such as the non-Newtonian power index (0.6 1) behavior reduces the fluid circulation and heat transfer rate in the cavity, but it increases the magnitude of the exerted tensions on the element. Moreover, raising Ra from 104 to 106 enhances the average heat transfer the value of Nuav by up to 3.5 times in pseudoplastic fluids and by 1.5 times in dilatant ones. In addition, it is found that shifting the heater upward deteriorates the heat transfer rate by suppressing the convection flow intensity. A 35% rise in the average heater can be obtained when the height of the plate was divided by 4 in the cse of dilatant fluid, and an increase by up to 100% is found for pseudoplastic fluids. Increasing the length of the element is also found to reduce the average Nusselt number and to increase the tensions in the heater. The average Nusselt number can be doubled when the length of the plate is reduced seven times.

Transformation Magnetohydrodynamics in Presence of a Channel Filled with Porous Medium and Heat Transfer of Non-Newtonian Fluid by Using Lie Group Transformations

In this paper, the numerical results are presented by using Lie group transformations, to be more efficient and sophisticated. To solve various fluid dynamic problems numerically, we present the numerical results in a field of velocity and distribution of temperature for different parameters regarding the problem of radiative heat, a magnetohydrodynamics, and non-Newtonian viscoelasticity for the unstable flow of optically thin fluid inside a channel filled with nonuniform wall temperature and saturated porous medium, including Hartmann number, porous medium and frequency parameter, and radiation parameter, with a comparison of the corresponding flow problems for a Newtonian fluid. Moreover, the effects of the pertinent parameters on the friction coefficient of skin and local Nusselt number were discussed numerically and also illustrate that graphically.

INVESTIGATION OF HEAT TRANSFER OF NON-NEWTONIAN FLUID IN THE PRESENCE OF A POROUS WALL

This study deals the investigation of heat transfer of non-Newtonian fluid in the presence of a porous bounding wall. Perturbation method is applied for the solution of non-linear differential equation. The main focus of this paper is to investigate the effects of parameters such as Reynolds number Re, Prandtl number Pr, permeability parameter K and n in the velocity of fluid and temperature coefficient. For fulfilling the purpose Matlab software has been used. The results show that velocity of non-Newtonian increases with increase of Reynolds number Re and temperature increases with increases of Prandtl number Pr.

Melting heat transfer of a non-Newtonian phase change material in a cylindrical vertical-cavity partially filled porous media

Purpose This paper aims to investigate melting heat transfer of a non-Newtonian phase change material (PCM) in a cylindrical enclosure-space between two tubes using a deformed mesh method. Design/methodology/approach Metal foam porous layers support the inner and outer walls of the enclosure. The porous layers and clear space of the enclosure are filled with PCM. The natural convection effects during the phase change are taken into account, and the governing equations for the molten region and solid region of the enclosure are introduced. The governing equations are transformed into non-dimensional form and then solved using finite element method. The results are compared with the literary works and found in good agreement. The non-Newtonian effects on the phase change heat transfer and melting front are studied. Findings The results show that the increase of non-Newtonian effects (the decrease of the power-law index) enhances the heat melting process in the cavity at the moderate times of phase change heat transfer. The temperature gradients in porous metal foam over the hot wall are small, and hence, the porous layer notably increases the melting rate. When the melting front reaches the cold porous layer, strong non-linear behaviors of the melting front can be observed. Originality/value The phase change heat transfer of non-Newtonian fluid in a cylindrical enclosure partially filled with metal foams is addressed for the first time.

Free convection around a slender paraboloid of non-Newtonian fluid in a porous medium

This paper emphasizes the radiative heat transfer of non-Newtonian fluid on free convection around a slender paraboloid in a non-Darcy porous medium. The Ostwald-de Waele power-law representation is employed to express the non-Newto?nian behavior of fluid. Similarity analysis is applied to transform the set of non-dimensional PDE into set of ODE and then the resulting system of equations are solved by 4th order Runge-Kutta scheme with Shooting technique. The control of pertinent parameters on velocity, temperature and non-dimensional heat transfer rates are analyzed through graphical representation and explored in detail. It is evident that as the radius of the slender body increases the heat transfer coefficient decreases but the role of radiation on heat transfer rate getting reduced for all feasible values of the power-law index parameter.

Slip Velocity in Flow and Heat Transfer of Non-newtonian Fluids in Microchannels

The steady-state fully-developed laminar flow of non-Newtonian power-law fluids is examined in a circular microchannel with slip boundary condition and under an imposed constant wall heat flux. Effects of slip as well as the hydrodynamic and thermal key parameters on heat transfer and entropy generation are investigated. The results reveal that increasing the Brinkman number and the flow behavior index both lead to increasing the entropy generation and decreasing the Nusselt number. In heating process, the temperature difference between the fluid and the wall decreases as the slip coefficient increases; similar trend may or may not be observed for cooling process, determined by the range of the slip coefficient as well as the Brinkman number. An increase in the slip coefficient leads to an increase in both the Nusselt number and the Bejan number, whereas it gives rise to a decrease in entropy generation. For each particular value of the slip coefficient, the Nusselt number approaches a specific value as the Brinkman number and/or the flow behavior index increases. An increase in the flow behavior index or a decrease in the slip coefficient results in incrementing the average entropy generation.

Numerical Simulation on Flow and Heat Transfer of Power Law Fluid in Structured Packed Porous Media of Particles

Flow and heat transfer of non-Newtonian fluid in porous media is an universal physical process in nature, industry and agriculture. With a certain concentration of HPAM aqueous solution (a typical power-law type non-Newtonian fluid) as the fluid medium, constructing the porous media skeleton model of orderly arrangement of spherical particles, the flow and heat transfer characteristics in three-dimensional orderly arrangement of porous media have been investigated numerically by using Fluent software. By employing the method of fluid-solid coupling subject to uniform heat flux, the effects of power law fluid rheological index, particle material, particle diameter and porosity on the flow and heat transfer characteristics are analyzed in detail. And also the concept of thermal efficiency is introduced to gain the comprehensive evaluation of its flow and heat transfer characteristics. The results show that the flow resistance decreases with the increase of the power-law index, particle diameter and porosity, and has nothing to do with the thermal conductivity coefficient of particles; while the local convection heat transfer coefficient increases with the increase of the power-law index and the thermal conductivity coefficient of particles, and decreases with the increase of particle diameter and porosity. The results can provide a theoretical basis for the flow and heat transfer mechanism of the power-law type non-Newtonian fluid flowing through the three-dimensional structured packed porous media of particles.

Lattice Boltzmann simulation of convective heat transfer of non-Newtonian fluids in impeller stirred tank

Lattice Boltzmann simulation of convective heat transfer of non-Newtonian fluids in an impeller stirred tank is performed. The curved and moving boundary methods combined with the unknown-index algorithm are used to solve the flow and thermal fields induced in a cold tank by an oscillating hot impeller. For a given maximum radius of the blades, the simulation results show that a rectangular impeller of large aspect ratio induces stronger heat transfer effect on the tank walls than the small aspect ratio. This is because the latter would cause worse field synergy than the former, i.e. the induced local velocities of fluid are mostly perpendicular to the temperature gradients. The convection effects on the tank walls are also improved as the oscillation amplitude of impeller increases until the swept areas of impeller are close to whole azimuth of the tank, i.e., oscillation amplitude of 90°. The maximum Nusselt number on the tank walls for power-law fluid flows of n=0.7, 1 and 1.5 occurs at oscillation amplitude of 75°. Finally, it is found that the heat transfer effect on the tank walls is reduced as the power-law index of fluid increases.

Study on Heat Transfer of Non-Newtonian Power Law Fluid in Pipes with Different Cross Sections

In industrial applications, most of fluids have non-Newtonian fluid characteristics. It is of great significance to the economic development and energy consumption reduction to study the heat transfer of non-Newtonian power law fluid. In this paper, the heat transfer of non-Newtonian power law fluid in pipes with different cross sections are studied. The mathematical model and physical model of the non-Newtonian fluid are briefly introduced first, and the physical model is divided by the structured mesh. Then the numerical simulation of the laminar heat transfer of non-Newtonian fluid in different cross sections is carried out. On the basis of discussing the distribution of temperature field, many parameters which have influenced on the temperature field and the heat transfer is analyzed in this paper, such as tube shape, the power-law index (n) the Peclet number (Pe) and so on. The results show that the heat transfer characteristics of non-Newtonian fluid are related to the parameters we mentioned.

Enhanced heat transfer in liquid thin film flow of non-Newtonian nanofluids embedded with graphene nanoparticles

Recent days, graphene is emanating as one of the most encouraging nanomaterials due to its continuous electrical conducting behaviour even at zero carrier concentrations. Heat transfer in non-Newtonian fluids plays a major role in technology and in nature due to its stress relaxation, shear thinning and thickening properties. With this incentive, we investigate the flow and heat transfer characteristics of electrically conducting liquid film flow of water based non-Newtonian nanofluids dispensed with graphene nanoparticles. For this investigation, we proposed a mathematical model for the flow of Jeffrey, Maxwell and Oldroyd-B nanofluids past a stretching surface in the presence of transverse magnetic field and non-uniform heat source/sink. Numerical results are carried out by employing Runge-Kutta-Felhberg integration scheme. The influence of pertinent parameters on reduced Nusselt number, friction factor, flow and heat transfer is discussed with the assistance of graphs. Embedding the graphene nanoparticles effectively enhances the thermal conductivity of Jeffrey nanofluid when compared with the Oldroyd-B and Maxwell nanofluids. Deborah number in terms of relaxation time plays a major role in convective heat transfer.

Flow structure and heat transfer of non-Newtonian fluids in microchannel heat sinks with dimples and protrusions

The flow structures and heat transfer of non-Newtonian fluids in a novel kind of microchannel heat sinks with dimples and protrusions were numerically investigated. The dimples and protrusions with a relative depth of 0.2 were vertically aligned to arrange on the opposite walls of the microchannel. The flow rate ranged from 3.72E−5 kg⋅s−1 to 8.69E−5 kg⋅s−1. The Fanning friction factor, form drag, frictional resistance, Nusselt number and thermal performance were analyzed to evaluate the overall thermal performance. Moreover, limiting streamlines and temperature distributions on the dimpled and protruded walls, as well as streamlines and dynamic viscosity distributions on the stream-wise middle sections, were used to investigate the effects of different parameters on the flow structure and heat transfer. New correlations of relative Fanning friction factor and Nusselt number were also proposed. It is shown that the heat transfer is enhanced, and the concentration of non-Newtonian fluids, flow rate and dimple/protrusion geometry have obvious combined effects on the flow structures and heat transfer. For the proposed microchannels, working substances with concentrations of 500 ppm and 2000 ppm are preferred.

Flow and heat transfer of non-Newtonian fluids in enameling dies

A widely used technique for the coating of magnet wires is passing them through enameling dies, from which they exit with a defined layer of enamel deposited on their surface. The generalized Couette flow, which emerges inside the converging annular gap between the moving wire and the stationary wall of the die, is computationally analyzed using the lubrication theory approximation. Non-Newtonian flow behavior and heat transfer are considered as well. The obtained results give a detailed insight into the effects of shear thinning/thickening on the velocity field and the wall shear stress along the wire. Despite the intense generation of viscous heat in the highly sheared region, the still moderate increase in temperature of the enamel does not pose any possible cooling problem. The influence of the die geometry on the drag force on the wire is examined by varying the axial contraction of the die, whose shape is assumed to follow a cosine-type function. The applied changes in the die geometry produce the same trends in the resulting drag force for all considered rheologies. The targeted reduction in the drag force could be achieved with the same die shape regardless of the flow behavior of the fluid. The predictions obtained from the lubrication theory based analytical model were validated against numerical results from computationally much costlier CFD simulations. This assessment proved the analytical model as a computationally efficient and reliable approach to describe the flow inside the die also for the fairly complex case of a shear thinning non-Newtonian fluid with temperature dependent viscosity.