Analysis Of Heat Distribution Research Articles

Impact of non-linear heat source and magnetic field on the Carreau nanofluid Marangoni convective flow – a numerical investigation

ABSTRACT A recent study examines the features of a dusty Carreau nanofluid over a flat surface with allowance for mixed convection that is not linear and heat radiation. It also examines how these factors affect fluid movement due to temperature differences (thermal Marangoni effect). The change in surface tension levels causes Marangoni convection, which finds applications in scientific areas like making crystals, keeping soap bubbles steady, drying thin wafers and dry silicon. Similarity transformations have been incorporated to create ODEs from PDEs. The complex non-dimensional differential equations are then solved using a numerical method called shooting method (with RKF-45 approach). For the momentum and heat distribution analysis, physical parameters are expressed in detail. The findings show that the Marangoni flow makes heat move quicker. In the same way, there is a decrease in the fluid’s velocity due to magnetic effects.

Heat Distribution Analysis of Resonant Power Converter in Non-starting Air Conditioner of Commercial Vehicles

Heat Distribution Analysis of Resonant Power Converter in Non-starting Air Conditioner of Commercial Vehicles

Temperature Distribution on Classical Two Needles IRE Setup Versus a Single Needle Prototype.

Irreversible Electroporation (IRE) is a non-thermal minimally invasive cancer therapy used in the treatment of liver tumors. However, the therapy entails an electrical current flux which can be high enough to cause a noticeable temperature increase. Therefore, the analysis of the heat distribution is important: during any IRE treatment, the target area is intended to be treated with non-thermal effects, where existing thermal effects should not damage nearby sensitive structures. This article aims to compare the established two parallel needles electrode setup, used by FDA-approved electroporation delivering devices, to a single needle, multiple electrode prototype design. Levels and distributions of the temperature at different distances from the applicators during an IRE liver treatment were investigated. The prototype results were collated with already published in-vivo data. All electrode configurations were analyzed numerically in COMSOL Multiphysics for different pulse protocols. The extension of coagulation necrosis predicted by the model matched available in-vivo data. While the maximum average temperature during pulsation was higher for the prototype (74 °C) than for the two-needle IRE setup (57 °C), the thickness of the coagulation necrosis around the conductive electrodes was in the same range for both configurations. However, the location differed completely: the necrosis engendered by the prototype was located inside the tumor, while the two-needle IRE setup created necrosis outside the tumor, potentially closer to sensitive structures. The results highlighted the importance of heat distribution analysis for the design of new IRE needles as well as for IRE treatment planning. Proper analysis ensures that the non-thermal effects are maximized while minimizing any potential thermal damage to surrounding sensitive structures.

Nonlocal thermal effects on biological tissues and tumors

• Analysis of heat distribution of tumor growth based on nonlocal rang effects. • The long-range kernel approach generalizes the Pennes bioheat equation. • Temperature is affected by nonlocal effects and by the localization of the neighbouring tumors. • The nonlocal kernel approach may imitate what is going on biologically within a tumor where cancer cells reside. Tumors consist of heterogeneous populations of cells. The cell–cell interactions processes play a critical role in cancer invasion and could be influenced by the mutation of cancerous tumor. This study is devoted to the analysis of the temperature distribution of tumor growth based on nonlocal range effects mainly the tumor-tumor influence incorporated in a kernel. The long-range kernel approach generalizes the Pennes bioheat equation which is the most commonly used formulation of heat transfer in biological systems. It was observed that the temperature is affected by nonlocal effects and by the localization of the neighbouring tumors. The nonlocal kernel approach may imitate what is going on biologically within a tumor where cancer cells reside. This may assist to the nonlocal treatment of cancer invasion in a human body.

Experimental and numerical investigation of heat generation and surface integrity of ZrO2 bioceramics in grinding process under MQL condition

Zirconia bioceramics has tremendous potential in medical applications owing to biocompatibility and high mechanical properties. Meanwhile, thermal damage and surface defects limit the grindability to achieve the desired properties. Therefore, this research provides an investigation of various grinding parameters on heat generation and surface morphology using a diamond wheel. In addition, a triangular and parabolic moving heat flux is used for heat distribution analysis based on FEM-model. The parabolic model more corresponds to experimental compared to the triangular heat flux, with an average deviation of <5% and 6.5% under dry and MQL, respectively. The response surface methodology is applied to extract a statistical representation of inputs and outputs. Dry grinding temperature obtained in range of 200–540 °C, which by applying MQL, it decreased by 16–35%. Increasing cutting depth would worsen the MQL efficiency in force and temperature. Results indicate the impact of cutting depth on temperature and force is greatest, followed by the effect of feed-rate, and that of wheel speed is the least. Thus, the increasing feed-rate should be utilized to preserve the high removal rate. SEM images indicate material removal mechanism is accomplished by plastic and brittle mode. Furthermore, MQL and a combination of low depth of cut could effectively decline the surface roughness and defects formation by decreasing the brittle material removal mechanism in one step. MQL reduced surface roughness by 46% compared with dry grinding, so that its performance increase in higher cutting depth. Because at higher cutting depths, the MQL changes the prevailing chip removal mechanism from brittle to ductile-regime grinding.

Investigation of in-plane heat distribution, thermal stability and mechanical properties of SS-(Fe3O4)/Ti/AlN/Ti/SiO2 as absorber coatings for efficient high temperature concentrated solar power systems

Despite numerous achievements recorded so far in developing solar absorber coatings for photothermal applications, the study of the thermal stability in humid and cold environment remains very scarce and the underlaying physics behind the transfer of the absorbed energy to the working fluid has never been investigated. In this perspective, we developed Ti/AlN/Ti/SiO2 film as multilayer selective solar absorber coating (MSSAC) on Fe3O4 modified stainless steel substrate using Direct Current (DC)/Radio Frequency (RF) magnetron sputtering at room temperature. The coating exhibited solar absorptance of 0.969 and thermal emittance of 0.220 in the solar and infrared spectrum regions respectively. The MSSAC was found to be thermally stable up to 500 °C in air. Further increase in annealing temperature to 600 °C resulted to a slight decrease in solar absorptance from 0.969 to 0.953 and a small rise in the emittance value from 0.220 to 0.258. A high humidity test and rapid heating-cooling cycling (RHCC) test revealed the stability of this coating and its potential application in humid (90 mmHg) and cold (− 50 °C) environments. Additionally, the coating shows good adhesion strength even after humidity and RHCC tests. The in-plane heat distribution analysis using thermal infrared imaging camera illustrated that there is a good possible transfer of the absorbed heat to the working fluid due to high surface temperature exhibited by Ti/AlN/Ti/SiO2 coated modified stainless steel (SS) substrate than the other boundary conditions. Overall, these results indicate that the present coating has the potential application in both high temperature, humid and cold environments.

Modelling and simulation of stress generation and temperature distribution in conical picks during linear coal-cutting process

The present paper is an extended version of the paper published by the first author [1]. In the previous work, a linear cutting of coal was done in various tilt angles. Two different conical picks, tungsten carbide tipped pick and hardened steel tipped pick, were used to cut the coal. An optimum tilt angle was found out by considering the three different parameters- amount of coal removed; depth of cut; temperature generated at the tip. The stress and heat distribution analysis could not be done in that work. The same research gap has been filled in the present work. An analysis of stress generation and heat distribution have been carried out in the present work by using modelling and simulation approach in FUSION 360 software. All the cutting parameters have been kept same as previous work. Maximum stress generation was identified at each tilt angle of the tool in both types of conical picks- conventional (tungsten carbide based) and new (hardened steel). The tilt angle between 0°-7° has been found safe as far as stress generation is concerned.

Thermal Analysis of Heat Distribution in Busbars during Rated Current Flow in Low-Voltage Industrial Switchgear

The manuscript presents advanced coupled analysis: Maxwell 3D, Transient Thermal and Fluent CFD, at the time of a rated current occurring on the main busbars in the low-voltage switchgear. The simulations were procured in order to aid the design process of such enclosures. The analysis presented the rated current flow in the switchgear busbars, which allowed determining their temperature values. The main assumption of the simulation was measurements of temperature rise during rated current conditions. Simulating such conditions is a valuable asset in order to design better solutions for energy distribution gear. The simulation model was a precise representation of the actual prototype of the switchgear. Simulations results were validated by experimental research. The heat dissipation in busbars and switchgear housing through air convection was presented. The temperature distribution for the insulators in the rail bridge made of fireproof material was considered: halogen-free polyester. The results obtained during the simulation allowed for a detailed analysis of switchgear design and proper conclusions in practical and theoretical aspects. That helped in introducing structural changes in the prepared prototype of the switchgear at the design and construction stages. Deep analysis of the simulation results allowed for the development concerning the final prototype of the switchgear, which could be subjected to the full type tests. Additionally, short-circuit current simulations were procured and presented.

STRAIN ANALYSIS OF REACTOR TYPE CORE STRUCTURES BY CONSIDERING UNCERTAINTIES OF GRAPHITE’S PROPERTIES

The power reactor with high-temperature gas-cooled reactor (HTGR) technology uses uranium as the reactor fuel. The energy from fission is converted to electrical energy or used for other needs such as hydrogen production or other research activities at high temperatures of around 700 °C. This operation does not allow the use of metal as the core material for the reactor. The material that fits the requirements as a core structure is graphite. Graphite material has specific characteristics, namely the parameters of the modulus of elasticity, coefficient of thermal expansion, and the volume which changes due to temperature and neutron dose. Because the structure of the reactor core is a vital component in the reactor, this research will develop a method for the design of the reactor core structure with graphite material. The design method is based on Design by Analysis which specifically refers to the strain analysis on each of the reactor core components. The design method developed is based on the finite element method. The object of this research is the side reflector made from the Toyo Tanso IG-110 series graphite. Based on the analysis of heat distribution and heat stress for the material before the effect of neutron exposure, the temperature distribution on the side reflector was found, as well as the displacement and heat stress that occurs. isotropic properties, Young's modulus and Poisson’s ratio values can be verified and estimated. The purpose of this research is to analyze the strain of the reactor core structure by taking into account the uncertainty of the graphite properties.

Mathematical modeling of moisture removal from granules

With modern world trends in the growth of consumption of products of various industries and the environmental situation, the problem of rational use of energy and raw materials in industrial production in order to obtain the maximum amount of finished product of a given quality. An important step in solving this problem is to create an adequate mathematical model of the process. A simplified model of the process of dehydration of the aqueous solution film on the surface of a single granule in the production of multilayer composites in a granulator dryer has been developed.&#x0D; Simulation of pellet dehydration includes analysis of heat distribution in a spherical material and in a film of liquid (heat exchange) covering the sphere, and the process of evaporation of the mixture film (mass transfer), which take place simultaneously.&#x0D; The results can be applied at the stages of design and testing of the granulator.

Theoretical Analysis of Heat Distribution in Raman Fiber Lasers and Amplifiers Employing Pure Passive Fiber

In this paper, we study the thermal dissipation of Raman fiber laser and amplifier utilizing pure passive fiber as gain medium for the first time. Take into account the convective and conductive heat transferring process in the fiber, we consider the heat transferring and Raman conversion model based on the thermal conduction equations and the Raman coupled equations in the fiber. With the simulation of power distribution, the thermal profiles of Raman fiber laser are analyzed, including the transverse and longitudinal distributions of the heat load density, temperature, and thermal-induced refractive index change in the fiber. Meanwhile, the heat dissipation in multimode graded-index fiber and step-index fiber are also calculated and compared. The results show that the amplifier is superior to the resonator in heat alleviation, and the forward pumping scheme is also better to ease the thermal load than the backward and bidirectional pumping schemes, which have consult meaning for the suppression of thermal effects and the power scaling in Raman fiber lasers.

Numerical Analysis of Thermal Effects in a Concept of a Cryogenically Cooled Yb: YAG Multislab 10 J/100-Hz Laser Amplifier

A thermo-optical design study of different slab geometries for a concept of a cryogenically cooled multislab amplifier operating at 10 J/ 100 Hz is presented. A finite element method (FEM) is used for 3-D analysis of heat distribution, temperature, stress, and strain. From this data, birefringence, depolarization losses, and wavefront distortion are calculated for a single pass through the amplifier consisting of four slabs. A comparison of different slab shapes shows that a square-shape geometry produces the smallest thermal gradients at the outer sides of the beam region, which results in smaller depolarization losses. Although the design with square-shape slabs is more sensitive to misalignment, our study shows better results compared to the case of circular-shape slabs.

Fabrication of InZnSiO/Ag/InZnSiO transparence flexible heater on polymer substrate by continuous roll-to-roll sputtering advanced technology

We fabricated highly effective and transparent film heaters based on a conductive Ag layer sandwiched in between InZnSiO films. This multilayer heater was deposited on a PET film at room temperature using pilot-scale roll-to-roll (RTR) sputtering machine. Due to the selected substrate, the heater was flexible and passed the 10 mm bending radius test. The InZnSiO/Ag/InZnSiO (IAI) multilayer heater displayed a high optical transmittance of 91.91% and a relatively low sheet resistance of 7.83 Ω/sq. This is an excellent chemical combination for fabricating a low voltage and transparent film heater. The time-temperature profiles and heat distribution analysis revealed that the best performance of the transparent film heater was at 2.4 V applied bias case. Due to high mechanical durability, high transparency and required low operating voltage the RTR sputtered IAI multilayer which can be considered one of the best candidates for fabricating highly flexible and transparent film heaters.

The study and application of evaluation methods for photovoltaic modules under real operational conditions, in a region of the Brazilian Southeast

This article presents the study and application of techniques for evaluating photovoltaic modules, in relation to dirt, temperature along with the main forms of visual degradation to which the materials constituting the photovoltaic modules of multicrystalline technology may be subject and their respective impacts on the performance of the generation of electric energy. To this end, 48 photovoltaic modules were analyzed from 5 different models, which totaled a power peak of 10.16 kWp derived from the photovoltaic system installed at the Research Laboratory of Power Electronics at the Federal University of Uberlândia-Brazil (NUPEP-FEELT-UFU). Initially, all the modules were appropriately cleaned. With the purpose of evaluating any endured degradation, a visual inspection was performed, and for the analysis of heat distribution across the surface of the modules, thermographic images were obtained and evaluated with the aim of identifying hots-pots, then these signs were related to the degradation identified during the inspection. In addition, with the objective to quantify the impact of failures in electrical performance, the curves I-V and P-V were measured in loco in 2017 and 2018, both individually and as a string, in order to obtain the main electric parameters.

An Analysis of Heat Distribution in the Production of SiC Process

Abstract SiC has been produced by the Acheson process in bulk. The efficiency of the process is quite low. Only about 15 to 18% of the total charge gets converted into SiC as against the theoretical value of about 42%. A heat transfer analysis of the process shows that it can be improved further to increase its efficiency. It has been done based on laboratory scale hot model unit and industrial furnace in terms of energy balance. This has been presented in this article. Based on the analysis, it is found that most of the losses in an industrial furnace occur due to the heating of charge by supplying excess electric energy than required and radiation. The latter has been improved at the laboratory scale furnace by enclosing the most part of the furnace.

Numerical and experimental analysis of heat distribution in the laser powder bed fusion of Ti-6Al-4V

ABSTRACTLaser Powder Bed Fusion (LPBF) of metallic parts is a complex process involving simultaneous interplay between several physical mechanisms such as solidification, heat transfer (convection, conduction, radiation, etc.), and fluid flow. In the present work, a three-dimensional finite element model is developed for studying the thermal behavior during LPBF of Ti-6Al-4V alloy. Two phase transitions are considered in the model: solid-to-liquid and liquid-to-gas. It is demonstrated that metal evaporation has a notable effect on the thermal history evolution during fabrication and should not be overlooked in contrast with the majority of previous research efforts on modeling and simulation of additive manufacturing processes. The model is validated through experimental measurements of different features including the size and morphology of the Heat-Affected Zone (HAZ), melt pool size, and thermal history. Reasonable agreement with experimental measurements of the HAZ width and depth are obtained with corresponding errors of 3.2% and 10.8%. Qualitative agreement with experimental measurements of the multi-track thermal history is also obtained, with some discrepancies whose sources are discussed in detail. The current work presents one of the first efforts to validate the multi-track thermal history using dual-wavelength pyrometry, as opposed to single-track experiments. The effects of selected model parameters and evaporation on the melt pool/HAZ size, geometry and peak predicted temperature during processing, and their sensitivities to these parameters are also discussed. Sensitivity analysis reveals that thermal conductivity of the liquid phase, porosity level of the powder bed, and absorptivity have direct influence on the model predictions, with the influence of the thermal conductivity of the liquid phase being most significant.

A Numerical Approach for Efficiency Analysis of Heat Distribution Through Fin

In this paper an analysis is carried out to study the efficiency of heat distribution through fins using finite element method (FEM) and differential quadrature method ( DQM). Numerical solutions are obtained using both methods for temperature distribution over the fin surface. Analysis of surface solutions in terms of temperature and error distributions have been presented here. Solutions are also obtained using equally spaced (conventional) and non-equally spaced (optimum) mesh (nodal points) distribution techniques. Two-dimensional heat conduction problem has been solved in both equal and non-equal nodal points distribution cases (called here conventional FEM (CFEM) and conventional DQM (CDQM) and optimum FEM (OFEM) and optimum DQM (ODQM)). The obtained results are compared and investigated with exact results. The best results are found in OFEM solutions. It is also found that, ODQM solutions reach very close to OFEM solutions with negligible error, whereas CFEM and CDQM solutions diverges with increasing number of nodal(mesh) points.

Self-assembled Ag nanoparticle network passivated by a nano-sized ZnO layer for transparent and flexible film heaters

We investigated a self-assembled Ag nanoparticle network electrode passivated by a nano-sized ZnO layer for use in high-performance transparent and flexible film heaters (TFFHs). The low temperature atomic layer deposition of a nano-sized ZnO layer effectively filled the uncovered area of Ag network and improved the current spreading in the self-assembled Ag network without a change in the sheet resistance and optical transmittance as well as mechanical flexibility. The time-temperature profiles and heat distribution analysis demonstrate that the performance of the TFTH with the ZnO/Ag network is superior to that of a TFFH with Ag nanowire electrodes. In addition, the TFTHs with ZnO/Ag network exhibited better stability than the TFFH with a bare Ag network due to the effective current spreading through the nano-sized ZnO layer.

Flow and heat distribution analysis of different transformer sub-stations

This paper describes CFD investigation on the flow and heat transfer in transformers at different sub-station buildings. The analysis aimed to determine the cooling capability of the existing transformer building employing natural ventilation system to dissipate heat sufficiently when new dry-type transformer operating under full load condition is used. The transformer and building models were developed based on the actual transformer configuration in operation at three different locations in Malaysia. The calculation was carried out on three different types of sub-stations namely stand-alone, attach-to-building and underground. The effect of natural ventilation speed and building volume on the transformer surfaces temperature are also investigated. It was predicted that the existing sub-station configuration is able to dissipate heat produced from the dry type transformer by using its natural ventilation system regardless of the sub-station types. However, the smallest building case shows relatively high surrounding temperature.

Finite Element analysis of heat distribution in laser beam welding of AISI 304 Stainless Steel sheet

Laser beam welding of AISI 304 austenitic stainless steel is performed by varying beam power, welding speed, beam angle and gas flow rate to identify the influencing process parameters on weld bead geometry. Finite Element (FE) simulations are carried out using FE software SYSWELD considering the thermo-physical properties of the base material. A three-dimensional conical Gaussian heat source is employed for performing non-linear thermal analysis. The transient temperature profile and weld bead dimensions; depth of penetration and bead width are calculated by FE simulation. The simulated bead profile is compared with the experimentally measured profile and found to be very well correlated.