Joule Heating Effect Research Articles

Flow and sensitivity analysis of viscoelastic material containing nanoparticles over a stretching sheet with Ohmic and viscous dissipation

The effects of Joule heating and viscous dissipation in the MHD flow of a viscoelastic (second-grade) fluid past a stretching sheet in the presence of metallic nanoparticles are studied. Copper nanoparticles are suspended in second-grade fluid with kerosene, water and polyvinly alcohol (PVA) that are supposed to be the base fluids. The mathematical equations that oversee the flow and heat transfer fields have been developed in the form of partial differential equations that are subsequently converted into a system of non-linear ordinary differential equations using the appropriate similarity transformation. The obtained equations are numerically solved and the impacts of different types of base fluids, solid volume fraction, magnetic number and Eckert number on the flow, temperature field, skin friction and Nusselt number are graphically analyzed. A sensitivity analysis is also utilized to identify the impact of involved parameters on skin friction and local Nusselt number. To predict the uncertainty caused by the involved parameters on skin friction and local Nusselt number, the Response Surface Methodology (RSM) is used. It is found that the volume fraction of nanoparticles does not cause uncertainty on skin friction, while the viscoelastic and magnetic number shows positive sensitivity at various levels. Also, Eckert number causes uncertainty on Nusselt number for lower values of the magnetic parameter.

The effect of Joule heating on collapse and water absorption of wood

ABSTRACT The effect of Joule heating on collapse, shrinkage, water absorption and compressive strength of timber was investigated. Results indicate that the tangential and volumetric collapse reduced significantly by ∼53% and ∼48%, respectively, with Joule heating in Eucalyptus nitens. Maximum tangential shrinkage was significantly lower, due to the reduction of collapse in Joule heated samples, as normal shrinkage was not affected by Joule heating. Reduction in collapse was achieved without a statistically significant increase in water absorption capacity or a decrease in compressive strength. Further, the estimated costs for Joule heating pre-treatment were estimated to be competitive compared to conventional steam recovery of collapse.

Axisymmetric Hydromagnetized Heat Transfer across a Stretching Sheet with Joule Heating and Radiation

This investigation thoroughly analyses magnetohydrodynamics axisymmetric fluid flow and heat transfer over an exponentially stretching sheet in the presence of radiation and Joule heating effects. The governing partial differential equation is obtained and converted into coupled ordinary differential equations using a suitable similarity transformation. This transformation is also used to re-model the governing system to modify ODEs and boundary conditions using the BVP4C MATLAB) package. The effects of the involved physical parameters, such as suction/injection parameter, magnetic parameter, Prandtl number, Eckert number, and radiation parameter on velocity and temperature profiles are shown graphically. The effects of various parameters on Nusselt number and skin friction coefficient are shown in tabular form. It has been determined that the presence of a magnetic field improves a fluid's thermal behavior. Furthermore, increasing the magnitude of the magnetic field reduces the fluid's radial velocity.

An exploration of polymer presence in magneto‐hydrodynamic flow and heat transfer past a magnetized stretching surface with effects of Joule heating

AbstractThe consequences of polymer presences on magneto‐hydrodynamic flow and heat transfer of a viscous fluid induced by a magnetized permeable heated stretching surface are studied in this article. The Lorentz force and Joule heating are also taken into consideration. The Oldroyd‐B model of polymers is used to study polymer presence which adds an extra stress in the mathematical model due to the polymer stretching. An iterative numerical scheme is opted to solve the set of ruling equations of the problem. Polymers stretch in the boundary layer region due to high velocity gradients. Polymer stretching reduces the zero‐shear viscosity near the surface but the polymeric viscosity (the total contribution of viscosity due to polymer addition) still remains positive, which cause velocity to reduce in the boundary layer region. Polymers are found to have no impact on the bulk. Skin friction along with heat and magnetic fluxes at the surface are evaluated with increasing polymer concentration. Zero polymer concentration represents the absence of polymers. Reduction in heat and magnetic fluxes and drag at the surface is observed in consequence of polymer addition. Polymer effects on skin friction, heat flux, and magnetic flux with respect to different values of magnetic force parameter, magnetic Prandtl number, magnetic interaction parameter, and the Eckert number are also thoroughly analyzed and graphically presented.

Multi-Physics Analysis of a Magnetorheological Valve Train with Experimental Validation

Magnetorheological (MR) fluid devices are widely used in active automotive control applications. However, MR fluid-based valve actuators are not in the limelight. This paper proposes a new flexible valve train with an MR fluid control system; the valve train can enhance the performance of internal combustion engines. A major component of this valve train is the magnetic plate block filled with MR fluid and surrounded by a magnetic coil. This plate block controls the magnetic field in this MR fluid and eventually facilitates flexible valve lifts and valve opening timings. This study overviewed the conceptual design, two-way coupled multi-physics numerical simulations, manufactured an MR valve prototype, and conducted experimental tests on a test bench to understand the real-time performance of the MR valve train. First, computer simulations were performed using a coupled magnetic and thermal multiphysics model to consider the Joule-heating effect of the magnetic coil in the MR magnetic plate block. The simulation results indicated that although the temperature of the MR fluid increased noticeably, it did not exceed the prescribed operating limits. The dimensions of the MR magnetic plate block were optimized. After computer simulations and optimization, a prototype of the proposed MR valve was fabricated and tested to understand its performance in real time. The experimental test results indicated the reliability of the proposed MR valve train in practical scenarios.

Magnetic proximity effect of YIG/PtSe2

The magnetic proximity effect has pronounced influence on the transport properties of bilayer system with a heavy metal and a magnetic insulator. Here we first review the magneto-transport properties of non-magnetic heavy metal/magnetic insulator bilayer structure and emphasize the role played by magnetic proximity effect. Since there are no current shunting and Joule heating effects within the insulating layer, it is relatively easier to understand the physical origin and impact of the magnetic proximity response for these bilayers. In the second part of this article, we study magneto-transport properties of YIG/PtSe2. YIG is known to have large band gap and low magnetization damping coefficient and is a frequently used magnetic insulator, while PtSe2 belongs to the family of two dimensional (2D) transition metal dichalcogenides in which spin–orbit coupling is strong. We found that the spontaneous magnetization in PtSe2 has been induced by the proximity of YIG, which results in a negative MR. Moreover, the AMR and spin Hall MR are both existed in YIG/PtSe2 system. The value of Anomalous Hall resistance can reach 1 Ω, which is much greater than that of the planar Hall effect due to the spontaneous magnetization in PtSe2.

Electrothermal Simulation and Optimal Design of Thermoelectric Cooler Using Analytical Approach

In this article, electrothermal modeling and simulation of thermoelectric cooling (TEC) in the package design of VLSI systems are performed by solving coupled heat conduction and current continuity equations. We propose a new analytical solution to the coupled partial differential equations (PDEs) which describe temperature and voltage with the reduction from 3-D to 1-D. In addition to this, we derive new analytic expressions for two key performance metrics for TEC devices: 1) the maximum temperature difference and 2) the maximum heat-flux pumping capability, which can be guided for the optimal design of thermoelectric cooler to achieve the maximum cooling performance. Furthermore, for the first time, we observe that when the dimensionless figure of merit <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$ZT_{0}$ </tex-math></inline-formula> value is larger than 1, there is no maximum heat-flux value, which means the heat dissipation due to the Peltier and Fourier transfer effects is larger than the heat generation caused by the Joule heating effect, which can lead to more efficient TEC cooling design. The accuracy of the proposed 1-D formulas is verified by a 3-D finite element method using COMSOL software. The compact model delivers many orders of magnitude speedup and memory saving compared to COMSOL with marginal accuracy loss. Compared with the conventional simplified 1-D energy equilibrium model, the proposed analytical coupled multiphysics model is more robust and accurate.

Dynamic Simulation of Electron Emission Characteristics Based on Different Numerical Models of a Nanoscale Micro-Protrusion

It is well known that electron emission is one of the key factors to cause electrical breakdown in vacuum gaps. In previous studies, it tended to use simplified numerical models with uniform electric field on emission region to investigate the electron emission characteristics at the cathode micro-protrusion and the influence of the materials of the micro-protrusions. The objective of this article is to introduce an improved numerical model of a nanoscale micro-protrusion with nonuniform electrical field on the emission region, which could be used for micro-protrusions with various irregular geometries. The improved numerical model is used in this article to study the dynamic characteristics of the electron emission of Cu and Cr micro-protrusions under different macroscopic electric fields. First, the electric field distribution is obtained by solving Laplace equation based on finite difference method (FDM). Then, the emission current and Nottingham effect are obtained by calculating the general thermal-field (GTF) equations based on the electric field distribution. Finally, the dynamic characteristics of the electron emission current and temperature distribution are iteratively calculated considering the Joule heating and Nottingham effect. The calculation results of the improved numerical model are compared with those of the previous simplified numerical model. The results show that for Cu and Cr micro-protrusions, the Joule heating, and Nottingham effect would play different roles in the emission process. In general, it is more likely for the Cr micro-protrusions to evaporate than the Cu micro-protrusions. The results of this article may provide some useful information to further understand the vacuum breakdown initiated by electron emission.

Comparison of temperature, current density, and light intensity distributions of nano-resistor patterns for an improved solid state incandescent light emitting device simulation model

The solid-state incandescent light-emitting device is an emerging optoelectronic device that is made on a silicon wafer using IC compatible materials and processes. Light emission takes place by thermal excitation of numerous nano-sized, high-resistivity conductive paths, i.e., nano-resistors, formed from the dielectric breakdown of an MOS capacitor. A simulation method that uses comsol multiphysics, python, and matlab to predict the temperature, current density, and light intensity distributions of various nano-resistor patterns in the device is presented. The Joule heating and blackbody radiation effects are correlated to the temperature and light emission profiles. The effect of mesh quality and depth on these distributions is also investigated. Electrical and optoelectronic properties of the nano-resistors calculated from this new program are consistent with the experimental results.

Combined effects of temperature-dependent properties and magnetic field on electro-osmotic mobility at arbitrary zeta potentials

ABSTRACT We analyze the thermo-electroosmotic mobility of power-law electrolyte solution under the action of a magnetic field in a wavy pattern micro-channel. The flow is driven by the combined effect of the pressure gradient and the electric potential applied externally in the axial direction. The variable properties such as the viscosity, zeta potential, electrical and thermal conductivity of electro-thermal flow are assumed to vary with temperature. The entire flow phenomena have been solved by employing the finite difference method. We have presented the variation of electroosmotic mobility with the effect of Joule heating and applied magnetic field. We have examined the coupling effects of axial velocity, thermal energy, and electric potential function for various values of the temperature-dependent properties. These temperature-dependent property variations lead to developing volumetric flow rates associated with the behavior of the power-law index. The Nusselt number is drastically influenced by the temperature-dependent zeta potential variation in comparison with the Newtonian and shear-thickening fluids. The numerical and analytical solutions are validated with the existing literature and obtained a good agreement.

Robust multifunctional rGO/MXene@PPS fibrous membrane for harsh environmental applications

Efficient cleanup of crude oil spills and wastewater treatment in harsh conditions remains a big challenge due to the absent of robust membrane materials. Herein, a kind of reduced graphene oxide and MXene (Ti3C2Tx) decorated PPS fibrous membrane with super chemical-resistance for all-weather cleanup of crude oil via Joule heat and solar-driven heat performance was reported. With the assist of the Joule heat and photothermal effect, the crude oil adsorption rate of composite membrane improved by more than 97 %. More importantly, the robust membrane still remained excellent oil/water separation performance even under strong acid and alkali conditions. Meanwhile, the gravity driven oil (dichloromethane)/water separation flux of composite membrane reached 11,502 L m-2h−1 with a separation efficiency up to 99.98 %. Moreover, the composite membrane could realize solar-driven evaporation for seawater desalination due to its great photothermal properties, the evaporation rate could be up to 1.235 kg m-2h−1 under one sun. The composite membrane also exhibited great electrical conductivity and EMI shielding performance for radiation protection with efficiency of 61.9 dB. This robust multifunctional fibrous membrane design offers a progressive approach for the efficient cleanup of viscous crude oil spills, oil/water separation, solar desalination and EMI shielding under harsh environments.

Flash sintering of Al2O3–ZrO2 ceramics under alternating current electric field

In this study, the influence of alternating current (AC) electric field on flash sintering and microstructural evolution of alumina–zirconia (Al2O3–ZrO2) composite was systematically investigated at furnace temperature of 800 °C. Compared with direct current (DC) electric field, AC electric field not only promoted densification and grain growth of Al2O3–ZrO2 composite, but also improved the uniformity of microstructure of ceramics. Grain size of AC flash-sintered samples was found to be inversely related to electric field, and positive correlation was observed with current density limit. Dense Al2O3–ZrO2 composite ceramic was fabricated via AC flash sintering under 60 mA mm−2 at low furnace temperature within 120 s, and as-sintered samples exhibited relatively good mechanical properties. The mechanism involving synergistic effect of Joule heating and defects generation under the influence of electric field was proposed to explain rapid densification during AC flash sintering. These results indicate the feasibility of preparation of dense composite ceramic with homogeneous microstructure via AC flash sintering.

Dual Solutions of Magnetohydrodynamics Al2O3+Cu Hybrid Nanofluid Over a Vertical Exponentially Shrinking Sheet by Presences of Joule Heating and Thermal Slip Condition

Hybrid nanofluid has an extensive range of real-world applications. Hybrid nanofluid is a new and advanced nanofluid modification extensively used to increase thermal efficiency in fluid flow systems. The main objective of this research is to study magnetohydrodynamics hybrid nanofluid flow numerically in two dimensional over a vertical exponentially shrinking sheet, considering the effects of Joule heating and thermal slip condition. Furthermore, using the Tiwari-Das model, the influence of the suction parameter on variations of reduced skin friction and reduced heat transfer is also explored. The hybrid nanofluid in this research is an Al2O3+Cu/water hybrid nanofluid, in which water is the base fluid, and two types of solid nanoparticles, namely Alumina (Al2O3) and copper (Cu), are combined together. The governing partial differential (PDEs) equations are transformed into the ordinary differential equations (ODEs) using exponential similarity variables. The resulting ordinary differential equations (ODEs) are numerically solved using the three-stage Labatto III-A technique in the "MATLAB software's" bvp4c solver. Hybrid nanofluids have greater thermal efficiency than nanofluids and base fluid. Dual solutions are obtained in specified ranges of suitable parameters. The temperature profile rises in both solutions as the Eckert value enhances. Besides, In the first and second solutions, the thermal boundary layer thickness decreased gradually as the thermal slip parameter increased. Finally, the conclusions presented that solution duality exists when the suction parameter , while no flow of fluid is possible when .

Electric‐field assisted ultrafast synthesis of Ti3SiC2 MAX phase

AbstractA galaxy of new two‐dimensional (2D) transition metal carbides, nitrides, and carbonitrides (MXenes) have outperformed other 2D nanomaterials in numerous promising applications due to their extraordinary properties. However, the synthesis of MAX phase is pertinent as it is the only precursor for the development of 2D MXenes. As many conventional MAX phase synthesis procedures are complex, time‐ and power consuming, we have introduced a novel electric‐field‐assisted flash sintering technique for a rapid synthesis of Ti3SiC2 MAX phase in both air and vacuum, facilitated by Joule heating effect. The flashing event was observed with an uncontrollable rise in current flow (∼255 mA/mm2) on the application of voltage in a range of 35–42 V/cm. Experimental outcome predicted that Ti3SiC2 MAX phase was synthesized by applying an electric field. Here we support the experimental findings through computational approach by using density functional theory calculations. We also report the synthesis of 2D Ti3C2TX MXene from flash‐synthesized Ti3SiC2 MAX phase. The scientific innovation discussed here could be a breakthrough in the rapid synthesis of different MAX phases with great potential for implementation in industrial scale.

Comparative Analysis of the Effect of Joule Heating and Slip Velocity on Unsteady Squeezing Nanofluid Flow

In this paper, we studied unsteady MHD nanofluid squeezing flow between two parallel plates considering the effect of Joule heating and thermal radiation. The governing equations in the form of partial differential equations (PDEs) are transformed into a system of ordinary differential equations (ODEs) with the help of similarity transformation. The obtained boundary value problem is solved analytically by optimal auxiliary function method (OAFM) and numerically by Runge–Kutta method of order 4 (RKMO4). The OAFM results are validated and compared to the results of RKMO4. The effects of physical parameters such as stretching parameter S , Prandtl number Pr , Eckert number Ec, magnetic number M , volume friction φ electric parameter E 1 , and porous parameter γ on the velocity, temperature, and concentration profiles are discussed with the help of plots. Also, the skin friction and Nusselt numbers effects are discussed with the help of tabular data. As the plates move apart, the Nusselt number and the skin friction coefficient decline and the Prandtl number decreases the temperature profile, whereas the stretching and Eckert number increases causing to increase the temperature field.

The Joule Heating Effect of a Foldable and Cuttable Sheet Made of SWCNT/ANF Composite.

A foldable and cuttable sheet heater was fabricated using single-walled carbon nanotubes (SWCNTs) and aramid nanofibers (ANFs). SWCNTs are particularly well suited for Joule heating based on their high thermal stability, electrical properties, high current density, and aspect ratio. When the SWCNT/ANF composite reaches a high temperature during Joule heating, ANFs will endure this temperature due to their impressive thermal stability, derived from aramid fibers. With the aim of achieving a synergistic effect between the SWCNTs and ANFs, 0–100 wt% SWCNT/ANF composite sheets were fabricated by tip-type sonication and vacuum filtration. After assessing the thermal stability and electrical properties of the composite sheets, the Joule heating effect was analyzed. TGA showed that our sheet had high thermal stability in an air condition up to around 500 °C. The electrical conductivity of the composite sheet was improved as the amount of SWCNT added rose to 790.0 and 747.5 S/cm in the 75 and 100_SWCNTs/ANF, respectively. The maximum heating temperature, up to 280 °C, reached by Joule heating was measured as a function of SWCNT content and input voltage, and the relationship among SWCNT content, input voltage, heating temperature, and electric power was described. Mechanical properties were also measured in a temperature range similar to the heating temperature of 300 °C reached by Joule heating. Ultimately, we obtained a foldable and cuttable composite sheet with a stretchable structure, capable of being molded into a variety of shapes. This energy-efficient material can potentially be employed in any device in which a heater is required to deliver high temperatures.

MHD williamson nanofluid flow in the rheology of thermal radiation, joule heating, and chemical reaction using the Levenberg–Marquardt neural network algorithm

Various studies have been conducted on the topic of predicting the thermal conductivity of nanofluids. Here, the thermal conductivity of nanofluids is determined using artificial neural networks since this approach is rapid and accurate, as well as cost-effective. To forecast the thermal conductivity of magnetohydrodynamic Williamson nanofluids flow through a vertical sheet, a feed-forward neural network with various numbers of neurons has been evaluated, and the best network based on the performance is selected. The fluid model incorporates the effects of Joule heating, heat generation absorption, thermal radiation, and a chemical reaction (MHD-WNF-HGA). A combination of heat radiation and reactive species improves the energy and solute profiles. The magnetic Reynolds number is assumed to be so small; therefore, the generated magnetic field has no effect. A postulate of similarity variables is used to convert the physical model in the form of nonlinear partial differential equations to an ordinary differential equation system. A supervised Levenberg–Marquardt backpropagation algorithm possesses a multilayer perceptron that is used for training the network, which is one of the top algorithms in machine learning. The bvp4c numerical technique is adopted to build the datasets for the construction of continuous neural network mapping. Flow, energy, and concentration profiles of the fluidic flow are constructed by adjusting several physical quantities such as the Williamson parameter, thermal radiation parameter, magnetic parameter, Eckert number, Darcy number, Brownian motion, and thermophoresis parameter. Analytical techniques such as error histogram graphs and regression-based statistical graphs are used to examine the accuracy of a suggested method. It has been found that the Levenberg–Marquardt backpropagation neural network mappings’ derivation, convergence, authentication, and consistency have been proven. Furthermore, thermal radiation assists the energy distribution to increase smoothly. Fluid velocity drops with the Williamson parameter, whereas thermophoresis impact enhances the strength of the nanofluid density.

Electro-thermal-mechanical coupled crystal plasticity modeling of Ni-based superalloy during electrically assisted deformation

Electrically assisted (EA) formation has attracted much attention in recent years. However, the multiscale deformation mechanism of materials under multifield (electrical, thermal, and mechanical fields) conditions remains unclear. In this study, an electro-thermal-mechanical crystal plasticity model was developed on the basis of the experimental findings of thermal and nonthermal effects of the pulse current in a superalloy during EA deformation. In this model, electrical resistivity was related to the applied current direction and crystallographic defects (e.g., dislocations) to account for the Joule heating effect. Additionally, the effects of electric current on the dislocation slip—in terms of reduction in the activation energy, softening of the slip resistance, and increase in the mobile dislocation evolution rate—were considered to describe the nonthermal effect. The model developed herein demonstrated that the Joule heating effect is locally distributed and is quantitatively related to the deformation, grain orientation, and dislocation density; the current-density threshold, which plays a role in reducing the dislocation density and slip resistance, was also determined. The existence of the stress difference under EA tension was compared with that under thermal loading with the same temperature history and was attributed to two aspects: (a) nonthermal effects, excluding similar thermal effects, and (b) local Joule heating effect. This model provides a method to quantitatively analyze the EA formation process, which will benefit process control.

Numerical prediction of Joule heating effect in electric hot incremental sheet forming

Since the deformation region involves the interaction of electric-thermal-force coupling in electric hot incremental sheet forming, the numerical simulation of the forming process is unusually difficult. Currently, the thermal-force coupling method is adopted to simulate approximately the whole forming process, and the Joule heating effect is often ignored. Therefore, the numerical simulation of the Joule heating effect is especially significant for the prediction accuracy of forming process. In this paper, a novel numerical simulation method considering electric-thermal-force parameters was proposed to update the thermal-force condition of the forming region instantly. Meanwhile, the model of contact thermal conductance was established, combining geometrical and electric-thermal parameters. Then a high-precision finite element model was obtained to predict the Joule heating effect of the forming region. In addition to this, the impact of thermal superposition on forming temperature was further analyzed, and a modified model of contact thermal conductance was established in electric hot incremental sheet forming.

Entropy Generation of Electrothermal Nanofluid Flow Between Two Permeable Walls Under Injection Process

This paper aims to study the electroosmotic nanofluid flow and heat transfer phenomena in a microchannel with porous walls by paying due attention to the interaction of the injected fluid velocity and the net charge density in the base fluid on the development of zeta potential and electroosmotic slip velocity. The novelty of this study is to obtain the integral expression for electroosmotic slip velocity which is found to converge to Smoluchowski velocity when the injected fluid velocity is low and porous permeability of channel wall becomes negligible. Under a weak electric field condition, the enhancement of pressure gradient is found to increase the normalized temperature and decrease the normalized nanoparticle concentration. The bulk nanofluid temperature is found to follow an almost quadratic relationship with applied pressure gradient. Additionally, in the absence of injection velocity, we observed a new expression for Soret number as a ratio of the cross sectional nanoparticle concentration to Joule heating parameter. Finally, a comparative study on the total entropy generation is carried out to minimize the loss of thermal energy due to irreversible physical mechanisms such as heat transfer, viscous dissipation and Joule heating effects that take place during the fluid flow process in a microchannel. It is thereby observed that the total entropy generation follows a quadratic relation with the Joule heating parameter in the absence of both injection and viscous dissipation. The increment in diffusive Reynolds number reduces EDL thickness near the upper channel bed. With an increment in the applied pressure gradient, the normalized temperature increases whereas the normalized nanoparticle concentration reduces.