Variation Of Temperature Field Research Articles

Quantitative correlation between temperature difference and sintering neck length in material extrusion-based additive manufacturing

The performance of polymeric parts fabricated via material extrusion-based additive manufacturing (MEAM) is significantly influenced by the sintering neck length between filaments. Despite its importance, elucidating the underlying mechanism governing the formation of inter-filament sintering necks is challenging due to the difficulties in monitoring temperature fields during MEAM. In this work, the thermal condition in MEAM was simplified using a printer with a tubular hotbed, coupled with a high temporal-spatial resolution infrared (IR) camera to monitor temperature field variations during printing. An advanced IR image processing method, integrating multi-directional retrieval and whole-loop average filtering, was developed to accurately measure temperature differences between filaments. By correlating these measurements with micro-CT characterizations, a quantitative relationship between temperature difference and sintering neck length was established. Through single- or multi-loop defect experiments, microscopic defect detection and analysis were conducted, achieving the prediction of sintering neck length variations at a 10 μm level with an 85 % accuracy. This work is believed to provide potential value for further accurate prediction of the mechanical properties of MEAM parts.

Short-Term Prediction Method of Transient Temperature Field Variation for PMSM in Electric Drive Gearbox Using Spatial-Temporal Relational Graph Convolutional Thermal Neural Network

Short-Term Prediction Method of Transient Temperature Field Variation for PMSM in Electric Drive Gearbox Using Spatial-Temporal Relational Graph Convolutional Thermal Neural Network

A study of layered holographic superconductor

We have investigated a holographic model of a multi-layered superconductor in (2+1)-dimensions using the AdS/CFT correspondence. This correspondence allows us to study strongly interacting condensed matter systems through a weakly interacting gravitational theory. Our study focused on the effects of a finite system size on the superconductor’s properties. We observed significant variations in the critical temperature and critical magnetic field depending on the number of layers and the spacing between them. Notably, our results capture the transition from a two-dimensional (2D) to a three-dimensional (3D) behavior in the limit of a large number of closely spaced layers. This transition signifies a change in how the superconductivity operates within real material.

A Study on the Plugging Effect of Different Plugging Agent Combinations during CO2 Flooding in Heterogeneous Reservoirs

Gas channeling control is key to improving CO2-flooding efficiency. A traditional plugging system has disadvantages, such as poor adaptability and stability, leading to the poor plugging effect of CO2 channeling in heterogeneous reservoirs and difficulty in controlling the subsequent CO2 injection pressure. To achieve a significant plugging effect and effectively control the subsequent CO2 injection pressure, a heterogeneous physical model of gas channeling in a horizontal well was established, and plugging experiments were conducted using four different combinations of plugging agents during CO2 flooding. Three evaluation parameters were defined, including the temperature field variation coefficient (TFVC), medium-permeability diversion rate (MPDR), and subsequent injection pressure coefficient (SIPC). The plugging effect of different combinations of plugging agents during CO2 flooding in heterogeneous reservoirs was analyzed. The results show that the plugging effect after using a combination of plugging agents was significantly better than after using a single plugging agent, and different plugging agent combinations had distinct characteristics. The strong–medium–weak (S-M-W) combination had the best MPDR for subsequent CO2 flooding, but the SIPC was the highest. The strong–weak–strong–weak (S-W-S-W) and weak–strong–weak–strong (W-S-W-S) combinations could effectively control the SIPC. These results indicate that plugging using the S-W-S-W and W-S-W-S combinations can achieve an effective plugging effect and reasonably control the subsequent CO2 injection pressure. This work provides a personalized design scheme for effective gas channeling control and maintenance of appropriate injection pressure during CO2 flooding in heterogeneous reservoirs.

A critical review of distributed fiber optic sensing applied to geologic carbon dioxide storage

AbstractIn the context of global climate change, carbon capture and storage (CCS) has become a direct and effective measure for reducing greenhouse gases emission. However, injecting CO2 into the subsurface reservoirs may pose risks related to geological hazards. Therefore, monitoring the variations in underground temperature fields, strain fields, and vibration fields induced by CO2 injection is essential for predicting and controlling geological hazards. Distributed fiber optic sensing (DFOS) technology, with its unique features, enables real‐time monitoring of temperature, strain, and vibration. By deploying fiber optic (FO) cables inside wellbores, a DFOS can be used to effectively capture multiple underground response parameters. This paper reviews the applications of DFOS technology in CO2 geological sequestration. The chapter covers aspects such as the literature review, principles and applications of fiber optics, and representative monitoring projects. Finally, the paper discusses the challenges and proposed solutions for DFOS technology in this context. © 2024 Society of Chemical Industry and John Wiley & Sons, Ltd.

Dynamic Analysis of an FGM Beam Undergoing Large Overall Motion in Temperature Field

The dynamic analysis of a functionally gradient material (FGM) beam undergoing large overall motion based on meshless methods is studied in the variable temperature field environment. Considering the high-order terms of nonlinear coupling deformation which were often ignored in previous studies, the high-order rigid–flexible coupled (HOC) dynamic model of a rotating FGM beam with a lumped mass in a temperature field is established by employing Lagrange’s equations of the second kind. Compared with the first-order approximate coupled (FOAC) dynamic model, the HOC dynamic model is more accurate and has a wider scope of application. The validity of the point interpolation (PIM) method and radial point interpolation method (RPIM) in this paper is verified by comparison with simulation results of the assumed mode method (AMM) and the finite element method (FEM). On this basis, the factors affecting the dynamic characteristics of the FGM beam such as the form of temperature field, the functionally gradient index, and the location of added lumped mass are discussed. In this paper, the meshless method with higher computational efficiency and the HOC dynamic model with more accurate results are adopted. This study will provide guidance and reference for dealing with problems in engineering, machinery, aerospace, and other fields in complex environment.

Research on lightweight design method of diesel engine steel piston based on heat transfer characteristics

Steel pistons are gradually replacing traditional aluminum–silicon alloy pistons as the preferred choice for high-power density engines. However, there is still a lack of systematic research on the heat transfer characteristics of steel pistons in the field of small bore diesel engines. For this reason, this paper was based on the storage temperature testing system to study the variation of temperature field and thermal stress in steel pistons of the small-bore diesel engine under the maximum torque conditions. The results show that there are significant temperature variations in the circumferential path of the steel piston head, indicating that the temperature distribution of the steel piston is highly uneven. The highest temperatures and maximum thermal stresses were found in the rim. To further achieve the lightweighting of the steel piston, a lightweight design method based on heat transfer characteristics was proposed. A multi-objective optimization algorithm was used to optimize the top land height and the position and shape of the cooling gallery. The structural design solutions with volume and thermal stress control were finally obtained. The optimized design solution can reduce the mass by a maximum of 10.01 %, the maximum temperature by a maximum of 35.04 °C and the maximum thermal stress by a maximum of 18.38 % compared to the original design.

Magnetoresistance and magnetic field-induced phase transition in two-dimensional antiferromagnet Fe1/3NbS2

We perform systematic studies on the magnetic and magnetotransport properties of Fe1/3NbS2 single crystal. Results show that Fe1/3NbS2 is an antiferromagnet with strong perpendicular magnetocrystalline anisotropy even in the paramagnetic state. The Fe1/3NbS2 nanoplate exhibits exotic magnetotransport characteristics with variation of temperature and magnetic field in the vicinity of Néel temperature. The temperature dependence of resistivity indicates that the magnetic field has a substantial effect on the Néel order of Fe1/3NbS2, and an intermediate phase occurs before the sample enters into the antiferromagnetic state. It is the field- or temperature-induced antiferromagnetic–intermediate phase and intermediate phase–paramagnetic phase transitions that lead to the novel magnetotransport characteristics in the vicinity of Néel temperature. The findings in this work will promote future studies based on two-dimensional antiferromagnetic spintronics.

Studies on selective laser quenching by high repetition frequency lasers with scanning galvanometer

This study introduces a novel material processing methodology termed High Repetition Frequency Selective Laser Quenching (HRF-SLQ). This technique utilizes high-power lasers with a maximum power of 5 kW in conjunction with a scanning galvanometer, operating at elevated repetition rates up to 200 Hz, to specifically treat surfaces of high and medium carbon steels. The application of this method leads to the creation of allotropic metal matrix composite materials (A-MMCs). In general, the scanning speed of a galvanometer can range from hundreds to thousands of times per second. Based on the high acceleration and rapid jumping characteristics of the scanning galvanometer, this technology transforms the high-power laser heating of metal plates from continuous heating mode to parallel pulse heating mode, which repeats heating 30 to 200 times per second. This transformation ensures the quenched layer avoids melting even under prolonged irradiation times by high-power lasers. Consequently, it can significantly enhance processing efficiency by selective laser quenching (SLQ), ensuring that the depth of the hardened layer reaches 0.88–0.94 mm and keeping the surface smooth without melting. This paper systematically investigates the influence of various processing parameters, such as laser power (P), single heating time (t1), and the number of processing units (N), on the depth of the SLQ and the quenching efficiency. It also examines the impact of HRF-SLQ technology on the properties of A-MMCs and analyzes temperature field variations from room temperature to melting point through simulation methods combined with laser quenching experiments.

Testing and identification method for the interfacial heat transfer coefficient between CFRTP and tools under fast hot-stamping conditions

Carbon fiber reinforced thermoplastic composites (CFRTP) are increasingly applied in automobile structures. Hot-stamping is a fast forming process for complex components of CFRTP. During hot-stamping process, the variations of temperature field occur in entire forming process, which ultimately have an impact on the forming quality and dimensional precision of the part. The interfacial heat transfer behaviour between CFRTP and tools directly determines the temperature distribution in the part. However, the existing heat transfer testing and identification methods are designed for sheet metal, which may not be applicable for CFRTP due to the differences in material properties and forming processes. Therefore, in this work, a new test device was developed to reproduce the interfacial heat transfer behaviour of CFRTP under various hot-stamping conditions, and an inverse identification method of the interfacial heat transfer coefficient (IHTC) between CFRTP and tools was proposed. The influences of contact conditions on the IHTC were investigated, including the interfacial contact pressure, interfacial clearance, heating temperature of tools and sheets. The results showed that the IHTC demonstrated a positive correlation with the contact pressure. However, the IHTC would significantly decrease with the existence of a clearance at the interface. Within the entire heat transfer process, it was also found that an increase in tool temperature resulted in a decrease in the IHTC, while initial sheet temperature didn't exert a significant influence. Furthermore, the reliability of proposed testing and identification methods had been verified by the hot-stamping for U-shaped CFRTP parts. The temperature error between the simulation and experiment was less than 5 %.

On‐Chip Multimode WGM Microresonator with Cross‐Correlation Algorithm for Enhanced Sensing

AbstractOptical whispering‐gallery‐mode (WGM) microresonators emerge as a frontrunner for precision measurement due to their high sensitivity and compact footprint. They have demonstrated superior capabilities in detecting a wide range of objects, spanning from variations in temperature, humidity, and magnetic field, to local perturbations caused by viruses or nanoparticles. Traditional methods often rely on monitoring spectral changes in a single WGM resonance to extract the relevant information of sensing targets. However, in scenarios involving multiple sensing targets of interest (e.g., molecule detection in a temperature‐fluctuating environment), analyzing only one resonant mode may be insufficient, leading to inaccuracies or misinterpretations in deriving target information. To address this issue, a multimode‐based cross‐correlation algorithm is proposed to distinguish local perturbations from global environmental fluctuations. For validation, on‐chip silicon microresonators and pulley bus waveguides are integrated for robust multimode excitation. A proof‐of‐concept experiment demonstrates the effectiveness of this method in detecting nanoparticles in an environment with temperature changes. This approach showcases versatility and applicability in various optical sensors, introducing new prospects for achieving high‐sensitivity sensing through scalable integrated photonic platforms.

Entropy and energy transfer analysis of a Maxwell thin‐film fluid over an inclined surface with viscous dissipation effect

AbstractNon‐Newtonian fluid plays a vital role in the field of manufacturing and engineering sector, because of its immense heat transfer rate. The two‐dimensional incompressible unsteady Maxwell nanofluid thin‐film flow with MHD and viscous dissipation over an inclined surface is investigated. One of the mechanisms in the second law of thermodynamics, that is irreversibility which also analyzed. The Maxwell nanofluid thin film energy and motion equations in the additional information have been turned into a coupled differential system of the third order. The transformed ODE equations are further evaluated by using the Homotopy Analysis Method (HAM). The variations of entropy rate, velocity, Bejan number and temperature field with the various emerging parameters are analyzed. This could potentially lead to the development of solar energy systems that are both affordable and highly efficient, so enabling the more efficient use of renewable energy sources and reducing our dependence on fossil fuels.

Study on transient thermal state of steel piston in diesel engine under cold start condition

The thermal load issue of pistons remains a topic of active research, especially the transient thermal state of steel pistons in diesel engines under cold start conditions has not been studied in depth. In this paper, a new steel piston power assembly was designed and developed on the basis of a small-bore diesel engine. A real-time temperature test system for the steel piston temperature field was developed to address the problem of the inability to obtain real-time temperature data. The test system was applied to the steel piston to investigate the transient variations in temperature field, thermal stress, and thermal deformation at different starting temperatures. The results show that the temperature field of steel pistons exhibits exponential growth in the early stage of cold start and then tends to stabilize after about 44 s. The lower the cold start temperature and the closer the monitoring points are to the high-temperature combustion gas, the faster the rate of temperature rise. The thermal stress of the steel piston initially increases rapidly, then decreases, and subsequently increases again until reaching a stable level. The lower the starting temperature, the longer the thermal stress inflection point of the monitoring point will be. The variation of thermal deformation of the steel piston follows the same trend as that of the temperature field.

Role of extrinsic factors on magnetoelastic resonance biosensors sensitivity

Magnetoelastic (ME) resonance devices are attractive for application as biosensors in health-related areas as they allow contactless detection of pathogenic agents with high sensitivity. After functionalization, they offer valuable diagnostic options that promote efficient capture of mass on the sensor surface through biological interactions. ME sensors are also sensitive to external factors such as temperature, magnetic fields, and variations in mass that can arise from processes unrelated to biological interactions, including corrosion and salt crystallization. This article evaluates extrinsic factors that affect the response of ME resonance sensors for diagnostic applications. In particular, the influence of heat treatments, operation temperature, applied DC magnetic field bias, and corrosive environment were studied. The control of all these factors is crucial for the design, fabrication, and functionalization of ME resonance biosensors and for the development of measuring instrumentation and effective measurement protocols. This work established maximum operating temperature and bias field variations to keep the sensor sensitivity. Heat treatment of the sensors before and after coating improved the signal-to-noise ratio and corrosion resistance. Further improvement in corrosion resistance was provided by cathodic protection, which has been proven beneficial for applications of ME resonance sensors in aqueous fluids.

Modeling of heat transfer in target material during the electron beam evaporation process

Numerical simulation provides a new method to study the heat and mass transfer behavior during the electron beam evaporation (EBE) process, which can obtain some physical quantities that cannot be accurately measured in experiments. In this study, a mathematical model is established to investigate the evaporation behavior, the variation of temperature field and flow field of target material during the EBE process, and verified through experiments. The results show that the evaporation rate of target material is extremely non-uniform on the molten pool surface, which the calculation error of the evaporation rate was 2.78 %. The solid-liquid interface obtained by numerical simulation is basically consistent with the experiment, which the calculation error of the molten pool depth was 3.57 % and the calculation error of the molten pool width was 1.18 %. In addition, the surface temperature and flow rate of the molten pool increased with the increase of the electron beam power, the depth and the width of the molten pool increased linearly with the increase of the electron beam power and then level off. The model can accurately describe the variations of temperature field and flow field during the EBE process, and then make reliable predictions based on the simulation results.

Temperature Field Characterization of Iron Tailings Based on Microwave Maintenance Technology.

Microwave maintenance technology, as a new development trend, can realize the environmentally noninvasive and rapid repair of asphalt pavement and gradually replace traditional maintenance methods. Iron tailings were used as a self-healing material in this study to investigate the temperature response matching of microwave maintenance technology. Firstly, the physical properties and the mechanism of iron tailings were elaborated through macroscopic physical index testing and microscopic X-ray diffraction (XRD) analysis. Secondly, the applicability of aggregates to microwave heating was demonstrated by analyzing the temperature rise characteristics of the granules using infrared imaging. Then, the temperature field variation rules of the iron tailing asphalt mixture were summarized by microwave heating Marshall specimens. Finally, the road performance was assessed by conducting high-temperature dynamic stability, low-temperature tensile, water immersion Marshall, and freeze-thaw splitting tests. The experimental results showed that the iron tailings can be used as an aggregate for high-grade asphalt pavement and as the preferred aggregate for microwave maintenance technology. The iron tailings temperature field was radial from the inside out to provide different temperature response states for different pavement diseases, so the asphalt was dissolved and precipitated in a short time. The particle size of iron tailings was inversely proportional to the wave-absorbing heating rate, and the heating efficiency of the small particle size (0-4.75 mm) was the highest. The specimens doped with 4.75-13.2 mm iron tailings showed the best heating performance and road performance, with the average surface temperature of the specimens reaching 126.0 °C within 2 min. In summary, according to different disease types and construction needs, iron tailings can be used as an aggregate for asphalt pavement, providing an appropriate temperature field and improving the efficiency of the microwave maintenance of asphalt pavements.

Micro-channel topology optimization based on enhanced heat transfer mechanism

Topology optimization modifies the material distribution in the design domain to produce micro-channel structure with improved thermal performance. In this work, five heat dissipation micro-channel structures with various design domain aspect ratios are optimally designed based on the bi-objective topology optimization method. The optimal design variable fields, temperature fields, and pressure fields are subsequently obtained for each operating condition, and the flow heat transfer effect and the enhanced heat transfer mechanism are investigated under various working conditions. On this basis, the flow heat transfer impact of micro-channels under various operating situations is optimized and studied by combining the field synergy concept and entransy dissipation theory. The findings show that when the Reynolds number rises in the laminar flow region, the complexity of the topological flow channels also rises. The average temperature, Tave,decreases, Nusselt number rises, the inlet and outlet pressure drop, ?P, gradually increases, the integrated enhanced heat transfer factor PEC gradually decreases, the field synergy number, Fc, increases, the pressure drop synergy angle, ?, gradually increases, the entransy dissipation, Evh, increases, and the flow heat transfer performance of each heat dissipation channel is also enhanced due to the complex channels and high Reynolds number in the domain. The investigation of micro-channels with various topologies revealed that the micro-channels with the same boundary conditions and a design domain aspect ratio of 25/64 had the best synergy effects of velocity-pressure gradient and velocity-temperature gradient, the best heat transfer effect, and the best flow characteristics.

Magnetic-field-induced spin reorientation in TmFeO<sub>3</sub> single crystals

TmFeO<sub>3</sub> exhibits rich physical properties such as magneto-optical effect, multiferroicity, and spin reorientation, making it possess significant research value in condensed matter physics and materials science. In this study, we utilize a time-domain terahertz magneto-optical spectroscopy system to investigate the changes in spin resonance frequency of TmFeO<sub>3</sub> single crystal at <i>T</i> = 1.6 K under external magnetic fields in a range of 0–7 T. The TmFeO<sub>3</sub> sample is grown in an optical floating zone furnace and its crystallographic orientation is determined by using back-reflection Laue X-ray photography with a tungsten target. The measurement setup is a self-built time-domain terahertz magneto-optical spectroscopy system, with magnetic fields in a range of 0–7 T, temperatures in a range of 1.6–300 K, and a spectral range of 0.2–2.0 THz. A pair of 1 mm-thick ZnTe nonlinear crystals is used to generate and detect terahertz signals through optical rectification and electro-optic sampling technique. The system variable temperature and magnetic field are controlled by a superconducting magnet. In experiments, a linearly polarized terahertz wave is vertically incident on the sample surface, and its magnetic component <i>H</i><sub>THz</sub> is parallel to the sample surface. By rotating the sample, the angle (<i>θ</i>) between macroscopic magnetic moment <i> <b>M</b> </i> and <i>H</i><sub>THz</sub> can be tuned, achieving selective excitations of the two modes, that is, <i>θ</i> = 0 for q-AFM mode and 90° for q-FM mode. Terahertz absorption spectrum results indicate that as the magnetic field increases, the quasi-ferromagnetic resonance (q-FM) of TmFeO<sub>3</sub> single crystal shifts towards high frequencies, and quasi-antiferromagnetic resonance (q-AFM) transits to q-FM under low critical magnetic fields (2.2–3.6 T). Through magnetic structure analysis and theoretical fitting, it is confirmed that the magnetic moment of the single crystal undergoes magnetic field induced spin reorientation. This study is helpful in better understanding of the regulation mechanism of the internal magnetic structure of rare earth ferrite under the combined action of external magnetic field and temperature field, and also in developing related spin electronic devices.

Study on temperature field distribution state of carbon fiber reinforced polymer wound circular tube via electromagnetic induction heating

The variation of temperature fields during the winding process of CFRP (Carbon Fiber Reinforced Polymer) due to fiber winding is a key factor influencing its curing and shaping. Traditional heating methods result in energy wastage and environmental pollution during the heating process. Electromagnetic induction technology, as a non-contact, pollution-free, and efficient heating method, is playing an increasingly significant role in the process of heating and curing CFRP. This study focuses on two heating methods, internal and external, for CFRP wound circular tubes. It establishes finite element analysis models for induction heating with different coil structures. The heating mechanisms of different coil-induced CFRP wound circular tube models are explained, and the effects of external arc-shaped coils and external/internal annular coils on the temperature field distribution of CFRP wound circular tubes are investigated. By comparing simulations with experiments, the correctness of the numerical analysis model in this study is demonstrated. It offers viable heating methods for different conditions in industrial production, providing theoretical support and empirical data for the induction heating of CFRP wound circular tubes.

МАТЕМАТИЧНЕ МОДЕЛЮВАННЯ ВНУТРІШНЬОСТРУКТУРНИХ ТЕРМОНАПРУЖЕНЬ, ЩО ВИКЛИКАЮТЬСЯ ПОЛЯМИ ЗМІННОЇ ТЕМПЕРАТУРИ В КОМПОЗИТАХ ЗІ СТРИЖНЕВОЮ АРМАТУРОЮ

Introduction. Thermomechanical effects arising in heterogeneous composite materials under the influence of temperature significantly affect the strength and durability of structures made of them. These effects have a special influence on the thermal deformation of bridge and road structures under conditions of seasonal and daily changes in ambient temperature. They are caused by non-uniformity of the thermomechanical parameters of its fractions and fittings. Until now, the phenomenon of thermomechanical deformation of reinforced structures has not been sufficiently studied, therefore the tasks of their research are urgent. Problem Statement. The problem of the performed research is to establish the laws of thermomechanical deformation of composite materials (including cement concrete and asphalt concrete), which are reinforced with reinforcing rods, in the fields of variable temperatures. Purpose. The purpose of the work is to derive mathematical ratios that determine intrastructural thermal stresses in composites caused by variable temperature fields and heterogeneity of materials.