Fluid Temperature Distribution Research Articles

Influence of radiation and thermal slip on electrically conductive dusty Walter’s B fluid moving peristaltically through an asymmetric channel

MotivationThe motivation of this recent article is to study dusty Walter’s B fluid flow due to its wide range of applications in biology and polymer industry. The fluid is traveling peristaltically through an asymmetric channel with wall slip. A discussion is also presented to examine heat transfer effects with thermal radiation and slip. MethodologyThe regular perturbation technique is employed to evaluate the mathematical model of the problem, which is first simplified by using stream functions. Mathematical results are simulated to illustrate flow characteristics of fluid and solid particles in salient quantities. Also, graphs of temperature distribution of fluid and dust particles have been discussed to study the impacts of various parameters. OutcomesWalter’s B fluid parameter reduces speed of both fluid and dust particles. By increasing thermal slip parameter, temperature transference becomes slower through the fluid, while Brinkman number significantly raises the temperature profile of both fluid and particles. This article presents a theoretical analysis of the problem. Moreover, the characteristics of liquids involved in the plastic industry and medical science can also be understood using the current analysis. Originality/ValueWalter’s B fluid with dust particle suspension has not been investigated for slip and thermal radiation effects.

Thermal slip and variable viscosity analysis on heat rate and magnetic flux through accelerating non-conducting wedge in the presence of induced magnetic field.

The focus of present study is to incorporate the variable viscosity and temperature slip impact on heating rate and induced magnetic gradient along the moving non-conducting wedge under magnetic field. In industrial and engineering procedures, the impact of induced magnetization improves the efficiency of thermal systems to main the heating rates. The similarity transformations and stream functions are applied to reduce the governing equations into ordinary form. During this transformation, the pertinent parameters such as wedge parameter, moving parameter, Prandtl factor, viscosity parameter and temperature-slip parameter is obtained. These parameters play a prominent role on the physical values of fluid velocity, induced magnetic field and temperature distributions. The skin friction, Nusselt coefficient and induced magnetic gradient are incorporated through these parameters. The numerical values are executed by using the Keller box analysis with Newton-Raphson technique. It is depicted that the maximum slip in fluid velocity and temperature distribution is obtained for each values of thermal-slip parameter. It is noticed that maximum magnitude in induced magnetic field is reported for each wedge factor. The maximum velocity slip and temperature slip is observed for each choice of moving parameter. It is reported that the maximum variation in heating rate and induced magnetic gradient is obtained for magnetic force and viscosity parameter. The enhancing behavior of skin friction is observed for maximum values of Prandtl number.

Dispersion of particles in a sessile droplet evaporating on a heated substrate

A coupled volume-of-fluid (VOF) and discrete element model (DEM) is developed and used to study the dispersion of particles in an evaporating pinned sessile droplet on a heated substrate. Fully resolved simulations of evaporating droplets are performed to study the effects of substrate temperature and the Marangoni stresses to study the fluid flow and temperature distribution within the droplet. The fluid flow inside the evaporating droplets is used to predict the behavior of particles, studying the effect of relative particle density and the aforementioned effects on the particle dispersion within the droplet. This study shows that the presence of Marangoni stresses significantly affects the flow and temperature distribution inside the droplet, which, in turn, influences the dispersion of particles in the droplet. The fluid velocity induced by the Marangoni stresses is nearly two orders of magnitude larger than the velocity generated by capillary flow as a result of evaporation, promoting a strong convective mixing within the droplet, while working to equilibrate the temperature distribution at the interface. In the absence of Marangoni stresses, the dispersion of particles is governed by the competing effects of adsorption by the downward-moving interface as a result of evaporation, and particle sedimentation under the influence of gravity. However, both these effects become less dominant in the presence of a flow induced by the Marangoni stresses, causing the particles to initially move toward the apex of the droplet along the interface and, subsequently, toward a stagnation point on the interface.

Thermal convection of a liquid metal under an alternating magnetic field

The objective of this work is to measure the heat transfer of a liquid metal in a cylindrical cell under the conjugate effects of a temperature difference and a Lorentz force generated by an alternating current in a coil. The experimental results are compared to recent direct numerical simulations (DNS) (Guillou et al., 2022). 25 experiments are performed for a large range of frequency f, ac intensity amplitude I0 and temperature difference between the top and bottom walls ΔT0: 15≤f≤1000Hz, 2≤I0≤67 A and 6≤ΔT0≤11 K. In these experiments, the Hartmann number Ha, the shielding parameter Sω and Rayleigh number Ra vary in the following range: 6≤Ha≤200, 1≤Sω≤70, 2.3×106≤Ra≤4.1×106. The experiments with an ac magnetic field are compared with the Rayleigh–Bénard convection (RBC) experiments under the same thermal conditions. Three rings of thermocouples allow characterizing the fluid temperature distribution during the convection. The heat flux at the bottom and top walls are also measured. We observe a very good agreement between the experimental results and the DNS results. As previously shown by numerical simulations, a master curve of Nu/Peω vs. QJ/Qc allows predicting the evolution of the heat transfer under different conditions of temperature difference and Lorentz force. Here Nu and Peω are the Nusselt number and a Péclet number based on the Lorentz force, and QJ and Qc are the total power deposited by the Joule effect and the total conduction heat flux without motion, respectively. The experiments show that Nu/Peω∼(QJ/Qc)−2/5.

Investigation of heat transfer enhancement and thermal stratification phenomenon on supercritical hydrogen fuel flow

Thermal stratification is one of the major issues in rectangular regenerative cooling channels because of the asymmetric heating and limited turbulent diffusion of thermal energy of the fuel. As a result, the heat transfer performance is decreased. This paper uses Ansys fluent software to construct a novel cooling structure that combines wavy wall surfaces with cylindrical fins. In addition to this new configuration, this study also examined three other configurations (straight-smooth, cylindrical-ribs, and wavy-smooth) and compared them with each other. This structure aims to efficiently enhance hydrogen coolant flow and heat transfer characteristics while reducing the extent of the non-uniform distribution issue. The results show that the new structure’s Nusselt number and maximum wall temperature are enhanced by 46.89% and 22.71%, respectively, compared to the straight-smooth structure; in contrast, the friction factor increased only by 3.64% over the smooth channel. The novel design has the best thermal performance factor compared to the other three designs, which is improved by 43.33% over the smooth channel. Among all configurations, the new structure is the best fluid temperature distribution configuration, which shows an optimal distribution of the coolant temperatures between layers; thus, the stratification phenomena decreased significantly.

Experimental and numerical studies on moisture adsorption/desorption characteristics across the circular fin tube desiccant coated heat exchanger

To improve the energy transfer abilities, enhance the quality of air, and curtail the growth of microorganisms, the desiccant coated heat exchangers are a capable substitute compared to conventional heat exchangers due to their capability of decoupling the sensible and latent loads and utilizing low-grade thermal energy. The concept of desiccant coated heat exchangers (DCHE) can be employed in various heat exchange/transport systems like heat pumps, atmospheric water harvesters, adsorption chillers, and air conditioners. Thus, in this research work, a circular fin tube desiccant coated heat exchanger (DCCHE) has been proposed and designed and a dynamic numerical model is established for simulating the combined heat and mass transport occurring across the adsorption/desorption process of a DCCHE employing finite element approach. The moisture and temperature distribution and flow of fluid are considered in the transient numerical model covering several domains such as water flow, air flow, and the coated desiccant. The desiccant material utilized in the current analysis is silica gel. The validation study showed good agreement, and the maximum error between the experimental result and simulated model for the humidity ratio of air and temperature of outlet air were observed to be ± 8 % and ± 7 %, respectively. A parametric analysis is carried out to assess the effect of varying the different input parameters on DCCHE’s performance. The field emission scanning electron microscopy results concluded that a uniform coating is formed on the circular fin surface. The experimental examination on the sorption kinetics of the silica gel showed that the moisture uptake capability was 0.34 g/g. Moreover, the proposed circular fin tube desiccant coated heat exchanger has been compared with the conventional plate type fin tube DCHE to assess its performance in terms of thermal coefficient of performance and specific dehumidification energy.

Numerical and experimental studies on the effects of molten steel viscosity on fluid flow, inclusion motion, and temperature distribution in a tundish

Tundishes are refractory vessels that are used to control the flow of molten steel, promote the removal of inclusions, and increase the homogeneity of temperature and composition during continuous casting processes by optimizing their geometric shape. The flow of molten steel in tundishes is a high-temperature process, and the optimization of the tundish structure is carried out by numerical and physical simulations. In numerical simulations, the viscosity of molten steel is generally set to a constant value; however, in industrial scenarios, the molten steel viscosity is variable with temperature. In the present work, the effects of molten steel viscosity varying with temperature on fluid flow, inclusion motion, and temperature distribution in a tundish were investigated by numerical simulations based on the modification of the top heat flux of the tundish, and the results were further verified by an industrial experiment. The removal rate of inclusions obtained from the industrial experiment was 40.40%. In numerical simulations, the inclusion removal rates were 50.85% and 40.67% when the fluid viscosity was constant and variable, respectively. Hence, when the molten steel viscosity was variable, the numerical simulation result was closer to the experimental one. The industrial experiment revealed that the temperature difference between the edge flow and the middle flow on the tundish liquid surface was 0 K. In numerical simulations, when the top heat fluxes of the tundish were 15 000 and 100 W/m2, the temperature differences on the tundish liquid surface were 5.95 and 0.16 K, respectively.

Thermal analysis of AIN-Al2O3 Casson hybrid nano fluid flow through porous media with inclusion of slip impact

A mathematical analysis of magnetized Casson hybrid nanofluid flow over a stretching permeable sheet with porosity effects and being exposed to thermal convective boundary conditions with slip in velocity and concentration have been presented numerically. The attained steady-state partial differential equations are highly coupled and nonlinear in nature and are not agreeable to any of the direct techniques. Hence, they are being reduced to coupled-nonlinear ordinary differential equations by means of appropriate similarity transformations. A MATLAB-based, bvp4c scheme has been employed to obtain numerical solutions. Suitable graphs have been plotted which demonstrates the fluid flow velocity, temperature, concentration and micro-organism distribution fields in the boundary layer regime. Magnifying Casson fluid parameter and porosity leads to a decline in the velocity field. Amplifying the concentration slip decays the concentration profile. A comparative analysis was conducted to confirm the findings from previous research, demonstrating strong consistency with the results previously documented. Enhancing heat transfer in microelectromechanical systems (MEMS), optimizing medical drug delivery techniques, and boosting the efficiency of cooling systems in industrial processes are all potential applications of this study.

Indirect mode solar drying of stevia (Stevia rebaudiana) leaves: experimental and numerical investigation of fluid flow pattern, moisture, and temperature distribution profile

Indirect mode solar drying of stevia (Stevia rebaudiana) leaves: experimental and numerical investigation of fluid flow pattern, moisture, and temperature distribution profile

Target Tracking Two Degrees of Freedom State Feedback Control for Continuous Flow Microfluidic Chips Temperature Controller

Microfluidic chips represent a cutting-edge technology for manipulating fluids within micrometer-scale spaces and are gradually becoming a new favorite platform in life science research. Precise and fast zonal temperature control is essential for accelerating biological experiments. However, current multi-channel temperature controllers typically rely on multiple channel sets to achieve single set-point control, which results in discrepancies between the fluid temperature distribution and sensor temperature due to the distributed temperature field in the fluid channel. To estimate the actual temperature and implement gradient temperature control, this paper introduces an extension of the target tracking (TT) two degrees of freedom (2DOF) state feedback control (SFC) method, followed by a presentation of simulation and experimental results. Through comparisons with an enhanced PID system in both simulation and experimentation, the paper demonstrates an 8.96% reduction in the maximum temperature difference across different regions and a 27.89% decrease in the time taken to reach various temperatures. This solution effectively addresses the existing challenges in temperature control for microfluidic chips, offering a more precise and stable control within the desired temperature range.

Finite difference simulation of natural convection of two-phase hybrid nanofluid along a vertical heated wavy surface

This study employs finite difference modelling to investigate the natural convection of a two-phase hybrid nanofluid consisting of Al 2 O 3 and Cu nanoparticles dispersed in water along a vertically heated wavy surface. The hybrid nanofluid has unique features that influence convective heat transfer. Numerical solutions analyze fluid flow patterns and temperature distributions, providing insights into heat exchange and thermal management. The research highlights the importance of hybrid nanofluids, notably those containing Al 2 O 3 and Cu in a water base, in improving overall heat transfer efficiency. The mathematical model accounts for laminar and incompressible fluid flow with a Prandtl number of Pr = 6.2, Lewis number Le = 10, and maximum 10 % concentration of hybrid nanoparticles. After transforming the governing equations into a non-dimensional form, the implicit finite difference method is used to solve them. The solution employs the in-house FORTRAN 90 code and compares its outcomes with the benchmark results. Various parameters, such as the Schmidt number (Sc = 1 to 10), volume fraction of nanoparticles ( ϕ = 0.0 to 0.1), wavy amplitude (A = 0.0 to 0.3), and N BT = (0.05 to 0.2), are investigated regarding temperature, velocity, local skin friction coefficient ( C f ) , local Nusselt number (Nu), streamlines, and isotherms. Elevated volume fraction generally decreases skin friction, increases temperature, and may reduce velocity. Meanwhile, higher skin friction, temperature, velocity, and local Nusselt numbers often correlate with elevated Schmidt numbers. Changes in amplitude and N BT affect skin friction, temperature, velocity, and local Nusselt numbers, providing information on the dynamics of fluid systems. For example, when the volume fraction (ϕ) increases from 0 to 0.1 at Y = 2, the temperature rises by 75 % , while the velocity gradually decreases by 11.11 % . This is in contrast to findings according to when the N BT rises from 0.05 to 0.2 at Y = 1. In this case, the temperature drops by 18.75 % , followed by a 9.68 % fall in fluid velocity. Understanding these interactions enhances comprehension of heat transfer and fluid dynamics. By investigating these interactions, we not only improve our understanding of heat transfer and fluid dynamics, but also open the door to new strategies for improving thermal systems and manufacturing procedures.

Thermal radiation and soret/dufour effects on amplitude and oscillating frequency of darcian mixed convective heat and mass rate of nanofluid along porous plate

The influence of thermal radiations and Soret/Dufour significantly increases the mass and heat transport in material science, geothermal process, chemical rectors and heat exchangers due to temperature and concentration variation of nanoparticles. Main objective is to enhance the amplitude, oscillation and frequency of heat transfer using the Soret and Dufour characteristics in Darcian radiating flow of thermophoretic nanoparticles along vertical porous surface. The dimensionless analysis is performed to develop the convenient form of governing thermodynamic Darcian nanofluid formulation. To develop the programming algorithm in FORTRAN language, the primitive variable formulation is used for both time-dependent and steady models. The numerical and graphical outcomes of primitive type equations under boundary conditions are explored by using implicit finite difference approach with Gaussian elimination scheme. Various pertinent parameters are used to elaborate the steady fluid velocity, surface temperature and steady concentrated nanoparticle volume fraction. Valuable novelty of current research is to use steady results for fluctuating shear stress, fluctuation heating rate and fluctuating mass rate. It is found that the influence of Soret and Dufour parameter enhances the fluid velocity and temperature distribution with maximum variations. It is noticed that the temperature distribution enhances as thermal radiation parameter increases. The oscillation and transient stability of heating rate enhances with prominent variations as thermal radiation and Soret/Dufour parameter increases. It is depicted that amplitude in shear stress and mass rate enhances as Soret and Dufour parameter enhances.

Designing & Developing a Porous based Box-Type Heat Exchanger for Enhanced Heat Transfer Rate

Abstract: The shell-and-tube heat exchanger's geometric configuration is optimized during the design development phase by taking into account various aspects like baffle spacing, tube arrangement, and overall system integration. Incorporating a blower into the system results in improved air circulation and effective heat transfer. By placing the band heater in a strategic location, air is heated precisely and locally, which helps to create a more responsive and controlled heating process. One essential tool for assessing the system's thermal and fluid dynamics is CFD analysis. The heat exchanger, blower, and band heater components' fluid flow patterns, temperature distributions, and pressure gradients are investigated through simulations. The CFD analysis provides valuable insights that guide design modifications aimed at optimizing heat transfer rates, minimizing pressure drops, and improving the integrated system's overall performance

Heat and mass transfer in magnetohydrodynamic boundary layer flow of second-grade nanofluid fluid past inclined stretching permeable surface implanted in a porous medium

ABSTRACT The current study deals with heat and mass transfer mechanisms in a non-Newtonian second-grade nanofluid model. The flow is induced by stretching the surface linearly and making it permeable and inclined at angle α=π/6. The fluid is saturated with a porous medium under transverse magnetic field and suction/injection effects. The proposed problem is in terms of partial differential equations, which are transformed into ordinary differential equations using the stream function formulation. The rigorous solver bvp4 has been used to solve the obtained differential equations. The results are presented in figures and tables and then discussed using physical justification. Graphs depict that the velocity of fluid increases and temperature distribution declines with the intensification of the second-grade fluid parameter at the considered angle of inclination of the stretching plate. It is observed that as the porous medium parameter is intensified, the velocity field declines rapidly. The temperature and concentration increase with increasing thermophoresis parameter. Increasing Brownian motion parameter results in augmentation in temperature and reduction in mass concentration. The current work’s results created with the use of this numerical method are compared with previously published results, which demonstrate great agreement between results, indicating accuracy and validation of the present results.

Flow and thermal characteristics of Jeffrey nanofluid in the fixed and moving frames of reference with newly developed Reynolds model

Nanofluids with their excellent thermophysical properties strengthen the thermal performance of an ordinary fluid. Due to the efficacious thermophysical characteristics of nanofluids, the aim of the present study is to discuss the three distinct viscosity models for an incompressible Jeffrey nanofluid relative to its oscillatory oblique stagnation point flow. Three different viscosity models namely Brinkman model, Einstein model, and Reynolds model are discussed to scrutinize the thermophysical attributes of (TiO2-Kerosene oil) nanofluid. The unsteady magnetized flow problem of Jeffrey nanofluid is deliberated over an oscillatory medium corresponding to different frames of references namely fixed frame and moving frame. The thermal analysis is evaluated with the involvement of heat absorption/generation and radiation effects. In both frames of reference, the non-dimensional equations are numerically handled via an efficient technique of bvp4c. The fluid velocity and temperature distribution are graphically compared regarding three distinct viscosity models with numerous pertinent parameters. In the context of all viscosity models, both the distributions of velocity and temperature exhibit excellent behavior in the fixed and moving frame of reference. This study exhibits that the parameter that portrays the ratio of relaxation to retardation times deteriorates the flow field in the fixed frame for all viscosity models.

Force convective heat transfer simulation in a rectangular channel with multiple square obstacles via finite element method

This study investigated fluid flow and forced convective heat transfer in rectangular microchannels with square barriers, as illustrated in Fig. 1 . In the first situation, three obstacles were positioned along the microchannel’s top wall. In the second scenario, obstacles were positioned along the microchannel’s bottom wall. In the final example, three square obstacles are placed symmetrically on either side of the microchannel wall. With the help of the Finite Element Method (FEM), we investigate the physicochemical behavior of the microchannel. The development of computer code within COMSOL multiphysics made it possible to simulate heat transport and fluid flow. The results include the implications of the rarefaction effect on fluid flow and heat transmission and decisions regarding the location of barriers and the shape of obstacles in squares. In addition, with the lowest value in skin friction and a lower Nusselt number, the third example, which has barriers on both sides, provides a valuable method for reducing the fluid temperature at the exit of the microchannel. This is because it has barriers on both sides. In the section under “Results and Discussion,” we provide an in-depth analysis of the numerical data derived from the microchannel. • Objective: This study aims to numerically investigate forced convective heat transfer in a rectangular channel featuring multiple square obstacles. The simulation employs the FEM to model fluid flow and temperature distribution. • Geometry and complexity: The channel geometry incorporates square obstacles, introducing geometric complexity. The FEM is chosen for its capability to handle intricate geometries accurately.

Thermal Analysis of MHD Hybrid Nanofluid on Stretching/Shrinking Non-Parallel Walls with Uncertain Volume Fractions

This study examines the heat transmission of magneto-hydrodynamic (MHD) hybrid nanofluid (Ag–[Formula: see text]O) flows between two stretchable or shrinkable walls. The nanoparticle volume fraction is considered an uncertain parameter and is represented using triangular and Gaussian fuzzy numbers. The governing radial momentum and energy equations are transformed into nonlinear ordinary differential equations using a similarity transformation and with the required boundary conditions. A generalized homotopy approach is used to analyze the impacts of embedding parameters, including the Reynolds number, stretching/shrinking parameter, opening angle, radiation parameter, Magnetic parameter, and solid volume fraction on velocity and thermal profiles in crisp and uncertain cases. The findings demonstrate that fluid velocity and temperature distribution increase as the stretching parameter increases. The correctness of the suggested technique is validated by comparing the results with the available numerical solution. It has been observed that there is a great agreement between the present results and the numerical ones.

Numerical investigation of supercritical flow and heat transfer mechanism in printed circuit heat exchanger (PCHE) channels

A numerical study is conducted to investigate supercritical hydrogen flow and heat transfer mechanisms and characteristics in printed circuit heat exchanger (PCHE) channels. The impact of large variations of the thermal-physical properties due to a wide range of operating temperatures have been studied and analyzed in detail. The heat transfer mechanisms of supercritical hydrgen under horizontal and vertical flow conditions are studied numerically. In addition, the influence of different cross-section shapes of the channel is also analyzed. The results show that asymmetrical fluid temperature distributions near the top wall and bottom wall due to the buoyancy effect result in heat transfer deterioration. Spiral flow occurs in the heat transfer deterioration region, which further confirms that the heat transfer deterioration is related to the spiral flow effect caused by the buoyancy effect. The heat transfer coefficient without gravity is lower than that with gravity, indicating that the buoyancy effect enhances the overall heat transfer in the horizontal circular channel. Furthermore, the fluid temperature in the vertical upflow channel decreases slowly from the near wall to the core area, while the fluid temperature in the vertical downflow channel changes sharply, which directly leads to the difference in the temperature gradient near the wall. Compared with the square cross-section channel and semicircular cross-section channel, the supercritical hydrogen can achieve greater heat transfer performance in the circular cross-section channel.

Design and Analysis of Biomass Gasification Reactor

Abstract: Biomass can be utilized as a renewable source of energy through various processes, and its theory involves understanding the principles of biomass composition, conversion technologies, and environmental implications. The objective of current research is to evaluate the thermal and fluid flow characteristics of gasification reactor using CFD tool. From the CFD tool, the temperature distribution at the combustion zone, mixing zone and exit zone are evaluated. The effect of turbulent mixing in gasification is evaluated. The application of Computational Fluid Dynamics (CFD) analysis in the study of biomass gasification reactors has proven to be a valuable tool for understanding and optimizing the complex processes involved. CFD simulations provide insights into the intricate interactions between biomass particles and gasifying agents, offering a detailed understanding of fluid flow patterns, temperature distributions, and species concentrations within the reactor.

Numerical investigation and thermal transport features of magnetic hybrid nanoparticles flow over a poignant tiny needle subject to Joule heating and slip boundary conditions

The primary purpose of this study is to provide more information on the stable and incompressible stream of a hybrid nanofluid over a poignant tiny needle in two dimensions under slip boundary conditions. In the hybrid nanofluid flow, Al2O3 and Fe3O4 are nanoparticles, water and ethylene glycol (50:50) are considered as the base fluids. Furthermore, the impacts of Joule heating and inclined magnetic fields are considered. The PDE’s governing equations are converted into ODEs by using similarity transformations and solved by a numerical technique based on Runge–Kutta fourth-order method. The results illustrate that the crucial parameters such as the magnetic parameter, Eckert number, nanoparticles of solid volume fractions, inclined angle parameter, and Prandtl numbers significantly affect the momentum and thermal profiles. The heat transfer rate and skin friction factors are used to calculate the numerical values of various parameters, which are displayed in a table. These analyses manifest that raising the magnetic parameter results in a decrease in the hybrid nanofluid velocity under slip and no-slip circumstances. The Nusselt number has also grown as a result of the volumetric fractions of nanoparticles and the intensification of the angle parameter. This analysis might include areas such as microfluidics, biomedical devices, heat exchangers, and other engineering applications where precise control over fluid behavior and temperature distribution is important.