Thermal Integration Research Articles

Integrated syngas biorefinery for manufacturing ethylene, acetic acid and vinyl acetate

The paper presents the design of an innovative process for manufacturing sustainable biochemicals, as acetic acid, ethylene and vinyl acetate monomer (VAM), in an integrated syngas biorefinery using renewable feedstock as biomethane and captured CO2. The work is supported by full design and simulation of six plants imbedded in a large process: syngas1 H2/CO 2:1 by catalytic partial oxidation of methane, syngas2 H2/CO 1:1 by dry methane reforming, methanol, acetic acid by carbonylation, ethylene and vinyl acetate. A key contribution is the development of a novel acetic-acid-to-ethylene process starting from syngas. This consists of catalytic hydrogenation of acetic acid (exothermic) followed by catalytic ethanol dehydration (endothermic). The thermal integration of reactors leads to low energy process and superior sustainability measures versus petrochemical and methanol-to-olefin processes. The comprehensive simulation of the integrated biorefinery allows getting consistent mass and energy balances, performing energy analysis and capital cost estimation, and finally delivering reliable sustainability measures. Based on syngas the carbon-yield, mass-yield, carbon footprint (kg CO2/kg product) and energetic requirement (MJ/kg) are 78.6%, 34.7%, 1.6 and 11.2 for ethylene, and 80.8%, 46.8%, 1.5 and 11.9 for VAM. At high biomethane price the ethylene may be costly but manufacturing the higher value VAM is fully profitable.

Efficient Thermal Integration Model based on a Biogas-fired Gas Turbine Cycle (GTC) for Electricity and Desalination Applications; Thermo-Economic and GA-based Optimization

As the global energy demand continues to rise, there is an urgent need to improve the efficiency and sustainability of power generation systems. This study integrated a modified supercritical carbon dioxide (S-CO2) and multi-effect desalination (MED) units to recover residual heat from a gas turbine cycle (GTC) in two stages, significantly enhancing electricity production while reducing the environmental footprint of the GTC. The significance of this study lies in its comprehensive approach, combining thermodynamic, environmental, and thermoeconomic analyses alongside thorough sensitivity evaluations. A triple optimization framework was implemented to optimize the system's performance, focusing on key metrics such as exergy efficiency, CO2 reduction rates, and levelized energy cost, utilizing the NSGA-II and the TOPSIS decision-making method in MATLAB software. Economic viability was assessed through a net present value (NPV) analysis, demonstrating substantial profitability. Finally, a comparison study of the devised system CO2 emissions rate was performed for different renewable energy sources. A specific application of the devised system is its capacity to generate 1.415 m³/h of distilled water while generating 1441 kW of electricity. Sensitivity analysis identified the combustion chamber temperature as the most critical design parameter, with a sensitivity index of 0.328. The optimum economic indicators showed marked improvement, with the NPV increasing from 2.371 M$ to 10.75 M$ and the payback period decreasing from 13.28 years to 7.18 years.

The Effect of a HealiAid ® Collagen Wound Dressing on Wound Healing in Patients: A Randomized Double-Blind Pilot Clinical Trial

Wound healing is a complex, multi-phase process. With rising healthcare costs, an aging population, and increasing chronic disease prevalence, the burden of wound care is escalating. Thus, finding safe and effective methods to accelerate wound healing is crucial. This study aims to explore the safety and efficacy of HealiAid® Collagen Wound Dressing in treating various types of wounds, including venous ulcers, diabetic foot ulcers, pressure ulcers, and burns. A clinical trial was conducted on 18 subjects with venous ulcers, diabetic foot wounds, pressure ulcers, and burn wounds. The study assessed the effectiveness of HealiAid in different wound types by analyzing its thermal stability, porous structure, biocompatibility, and clinical efficacy. Wound healing was strictly monitored, and the safety and tolerability of the dressing were evaluated. The results showed that HealiAid Collagen Wound Dressing has excellent thermal stability and structural integrity. Its porous microstructure enhances cell adhesion and tissue regeneration, demonstrating significant healing effects across various wound types, including venous ulcers, diabetic foot wounds, pressure ulcers, and burns. No serious adverse reactions were reported, and endotoxin levels were well below safety standards. This study confirms the safety and efficacy of HealiAid Collagen Wound Dressing in treating multiple wound types. Its outstanding thermal stability, porous structure, and biocompatibility make it a promising option for clinical wound care

Efficiency enhancement of a combined cycle power plant by thermal integration of multiple waste heat streams with organic Rankine cycle

AbstractThe study investigated the efficiency improvement of a 9.5 MW gas engine‐based combined cycle power plant utilizing multiple waste heat streams in an organic Rankine cycle. Four different waste heat sources were considered: I) boiler stack gas, II) engine jacket water, III) boiler steam, and IV) engines' exhaust gas. Besides, three different organic fluids; R245fa, R134a, and R1234ze(Z) were employed to find the best working fluid in the given operating conditions. The performance analysis of the ORC revealed that R245fa is a suitable potential fluid for cases I and II, whereas R134a performs better for cases III and IV. Integrating the ORC with the boiler stack using R245fa at 8 barg provided an additional 16.5% waste gas heat recovery. It increased the net electric efficiency of the existing plant by 0.7%. The jacket water heat recovery further improved the net electric efficiency by 2.1%. By integrating both streams with the ORC in the existing system, the net electrical efficiency was increased from 42.6% to 45.3%. The estimated payback period for the jacket water heat recovery scenario utilizing Chinese ORC equipment was 9.3 years. However, this period was significantly reduced to 4.6 years for general industry applications, rendering it economically viable.

Development of a Versatile and Reversible Multi-Stack Solid Oxide Cell System towards Operation Strategies Optimization

Abstract In context of Temperature Electrolysis based on Solid Oxide Cell technology, CEA LITEN has developed a new investigation tool (MURPHY) devoted to the operation of several Solid Oxide stacks. MURPHY enables stack operation in both the electrolysis (SOE) and the fuel cell (SOFC) modes. For the later, H2, CH4, and natural gas can be used as fuel. A compact Balance of Plant (BOP) is designed to (i) provide air by centrifugal blower, (ii) target high thermal integration and performances, (iii) preheat inlet gases, (iv) recycle fuel exhaust, and (v) control pressure levels. Instrumentation was defined to support modeling development and accurate process efficiencies characterization. 
MURPHY is currently compatible with four stacks of CEA standard base design (25 cells, of 100 cm² active area), the corresponding maximum power range of the module is -16/4 kWDC for supply and venting of gases produced.
This report details system architecture. It also puts forward experimental results related in an environment controlled by thermal phenomena. Performance and efficiency curves obtained under parametric variations of temperature and flowrates are reported for both SOE and SOFC-H2 modes. A special attention is given to heat performance. In this view, flow parameters at several locations over circuitries are provide

Thermal Integration in Sugar Production Using Pinch Analysis

Objective: the objective of this study is to conceptualize a network of heat exchangers designed to minimize energy waste and enhance the overall efficiency of the sugar production system.Methods: a systematic approach was adopted to analyze energy flows within the plant, identifying key areas for improvement, particularly in heating and evaporation processes. Heat accumulations in cascades and graphical analyses of composite curves were developed using specialized software to optimize heat exchange.Results: the results indicate a significant potential for energy savings, reducing the consumption of cooling and heating utilities in the plant by 7% and 30%, respectively. The developed computational tool allows for energy integration from simple processes to those with hundreds of streams. The pinch technology concept estimated an annual total savings of $464,850.08 in the selected process.Conclusion: this study demonstrates that thermal integration through pinch analysis not only improves energy efficiency in the sugar industry but also contributes to a considerable reduction in operational costs and environmental impact, providing a valuable tool for the industry’s sustainability and competitiveness.

Experimental study on physico-mechanical responses and energy characteristics of granite under high temperature and hydro-mechanical coupling

Thermal and hydro-mechanical coupling effects on granite's physico-mechanical responses and energy characteristics can influence its carrying capacity, hydraulic and heat transfer performance. The evolution of these properties is crucial for geothermal reservoir stability assessment and the optimization of deep geothermal energy development techniques. Hence, a variety of physical tests and rock mechanics experiments were conducted. Key findings include: (1) As temperature rises, granite undergoes thermal expansion and structural integrity degradation. The peak strength σp, elastic modulus E, total energy density U, and elastic energy density Ue initially rise at 25 °C–150 °C and subsequently decrease above 150 °C, while the proportion of dissipated energy ηd is opposite. Granite also initially experiences hardening, then turns to brittle-ductile transition. (2) The crystallinities of quartz, albite, and orthoclase demonstrate substantial deterioration beyond 450 °C. (3) 150 °C and 450 °C are regarded as the temperature thresholds for mechanical properties. (4) As confining pressure rises, granite experiences hardening, with σp, E, U, and Ue increasing, and ηd decreasing. (5) Pore water pressure increases ηd and decreases σp, E, U, and Ue, and its effect on the mechanical responses is pronounced when it reaches 80 % of confining pressure or exceeds 450 °C.

Design, fabrication, and calibration of a micromachined thermocouple for biological applications in temperature monitoring

This paper presents a microneedle thermocouple probe designed for temperature measurements in biological samples, addressing a critical need in the field of biology. Fabricated on a Silicon-On-Insulator (SOI) wafer, the probe features a doped silicon (Si)/chrome (Cr)/gold (Au) junction, providing a high Seebeck coefficient, rapid response times, and excellent temperature resolution. The microfabrication process produces a microneedle with a triangular sensing junction. Finite Element Analysis (FEA) was employed to evaluate the thermal time constant and structural integrity in tissue, supporting the probe's suitability for biological applications. Experimental validation included temperature measurements in ex-vivo tissue and live Xenopus laevis oocytes. Notably, intracellular thermogenesis was detected by increasing extracellular potassium concentration to depolarize the oocyte membrane, resulting in a measurable temperature rise. These findings highlight the probe's potential as a robust tool for monitoring temperature variations in biological systems.

Hardware Testing Methodologies for Wide Bandgap High-Power Converters

Wide bandgap (WBG) power semiconductor devices are increasingly replacing silicon IGBTs in high-power and high-voltage power electronics applications. However, there is a significant gap in the literature regarding efficient testing methodologies for high-power and high-voltage converters under constrained laboratory resources. This paper addresses this gap by presenting comprehensive, hardware-focused testing methodologies for high-power and high-voltage WBG power semiconductor-based converter bring-up before the control validation phase steps in. The proposed methods enable thorough evaluation and validation of converter hardware, including device switching characteristics, driving circuit functionality, thermal management performance, insulation integrity, and sustained operation at full power. We utilized the double pulse test (DPT) to characterize switching performance in a two-level phase leg configuration, extract circuit parasitics, and validate magnetic components. The DPT was further applied to optimize gate driving circuits, validate overcurrent protection mechanisms, and measure device on-resistance. Additionally, a multicycle test was introduced to rapidly assess steady-state converter performance and estimate efficiency. Recognizing the critical role of thermal management in high-power converters, our methodologies extend to the experimental extraction of key thermal parameters—such as junction-to-ambient thermal resistance and thermal capacitance—via a heat loss injection method. A correlation method between temperature sensor measurements and junction temperature is presented to enhance the accuracy of device temperature monitoring during tests. To ensure reliability and safety, dielectric withstand tests and partial discharge measurements were conducted at both component and converter levels under conventional 60 Hz sinusoidal and high-frequency PWM waveforms. Finally, we highlight the importance of testing converters under full voltage, current, and thermal conditions through power circulating tests with minimal power consumption, applicable to both non-isolated and isolated high-power converters. Practical examples are provided to demonstrate the effectiveness and applicability of these hardware testing methodologies.

DEVELOPMENT OF ADVANCED COMPOSITIONS INCORPORATING WOLLASTONITE, THERMOVERMICULITE, SILICON IV OXIDE, AND AEROSIL

This study presents the development of innovative composite materials by incorporating wollastonite, thermovermiculite, silicon IV oxide (SiO₂), and aerosil. The primary objective was to formulate high-performance materials with enhanced mechanical, thermal, and structural properties suitable for industrial and construction applications. Wollastonite and thermovermiculite, known for their excellent reinforcing properties, were combined with SiO₂ and aerosil to create a hybrid matrix. The materials were synthesized and characterized using techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), and thermal gravimetric analysis (TGA). Experimental results revealed that the new compositions exhibited superior heat resistance, improved strength, and enhanced durability compared to traditional materials. The inclusion of aerosil, with its fine particle size and high surface area, contributed to improved dispersion and homogeneity within the matrix, resulting in enhanced thermal stability and mechanical performance. These advanced composites hold great potential for applications in areas requiring robust thermal and structural integrity, including insulation, construction materials, and high-temperature industrial components. Future work will focus on further optimizing these formulations and exploring their use in specialized engineering fields.

Comparative investigation of structural, morphological and temperature-dependent photoluminescence characteristics of trivalent rare-earth-activated NaCaPO4 phosphors for solid-state lighting applications

This study explores the synthesis, structure, morphology, and photoluminescence features of trivalent RE3+-activated NaCaPO4 phosphors, aiming to develop phosphor materials for white-light-emitting diode (WLED) applications. Single-phase polycrystalline NaCa(1-x) REx3+ PO4 (REx3+ = Sm, Eu, Dy, and Tb) phosphor materials with various REx3+-doping percentiles were produced by a solid-state reaction process, which were analyzed using various characterization techniques. The FullProf Suite software program was used for phase evidence and crystalline structure analysis, confirming the composition of orthorhombic materials as a single phase. FE-SEM micrographs revealed asymmetrically stacked morphologies across all the compositions. This study reveals that trivalent RE3+-activated phosphors produced exceptional PL outcomes. Dexter's and Blasse's approaches were used to establish the interaction mechanisms and critical energy transfer ranges as dipole-dipole. Lifetime decay patterns were used to fit a bi-exponential function and the resulting values were approximated in milliseconds. This study reveals that trivalent RE3+-activated NaCaPO4 phosphors, with their thermal resilience and color integrity, have potential applications in solid-state lighting (SSL) technology.

Sustainable Biomethanol and Biomethane Production via Anaerobic Digestion, Oxy-Fuel Gas Turbine and Amine Scrubbing CO2 Capture

Energy policies around the world are increasingly highlighting the importance of hydrogen in the evolving energy landscape. In this regard, the use of hydrogen to produce biomethanol not only plays an essential role in the chemical industry but also holds great promise as an alternative fuel for global shipping. This study evaluates a system for generating biomethanol and biomethane based on anaerobic digestion, biogas upgrading, methanol synthesis unit, and high-temperature electrolysis. Thermal integration is implemented to enhance efficiency by linking the oxy-fuel gas turbine unit. The integrated system performance is evaluated through thermodynamic modeling, and Aspen Plus V12.1 is employed for the analysis. Our findings show that the primary power consumers are the Solid Oxide Electrolysis Cell (SOEC) and Methanol Synthesis Unit (MSU), with the SOEC system consuming 824 kW of power and the MSU consuming 129.5 kW of power, corresponding to a production scale of 23.2 kg/h of hydrogen and 269.54 kg/h of biomethanol, respectively. The overall energy efficiency is calculated at 58.09%, considering a production output of 188 kg/h of biomethane and 269 kg/h of biomethanol. The amount of carbon dioxide emitted per biofuel production is equal to 0.017, and the proposed system can be considered a low-carbon emission system. Key findings include significant enhancements in biomethanol capacity and energy efficiency with higher temperatures in the methanol reactor.

Life cycle and techno-economic analyses of biofuels production via anaerobic digestion and amine scrubbing CO2 capture

The global energy landscape highlights the importance of the hydrogen economy, emphasizing its critical role in worldwide energy policies. This study explores a system designed for producing biomethanol and biomethane by integrating anaerobic digestion, biogas upgrading, and high-temperature electrolysis. The system builds on real-scale industrial data from an existing anaerobic digestion plant, which has been expanded to include biogas upgrading, an oxy-fuel gas turbine, a Solid Oxide Electrolysis Cell (SOEC), and a methanol production unit. Hydrogen, generated through electrolysis, synthesizes biomethanol by reacting with CO2. Additionally, the system produces biomethane through biogas upgrading. The system incorporates thermal energy integration with an oxy-fuel gas turbine. Life cycle assessment (LCA) results demonstrate the system’s environmental potential, achieved negative CO2 emissions of −0.0075 kgCO2eq/kgBiomass in case of photovoltaic panels and −0.0096 kgCO2eq/kgBiomass in case of wind turbines as electricity sources, attributed to efficient conversion of sewage sludge into valuable biofuels. Thermodynamic modeling in Aspen Plus shows an energy efficiency of 58.09 %, with outputs of 188 kg/h of biomethane and 269 kg/h of biomethanol. The techno-economic analysis reveals a payback period of 6.11 years and a levelized cost of biomethanol of 294.37 € per ton, indicating the system’s economic viability. The LCA further underscores the system’s sustainability, supporting its environmental benefits. This comprehensive analysis provides valuable insights into the viability and environmental impact of the proposed biofuel production system.

Enhancing Power and Thermal Gradient of Solar Photovoltaic Panels with Torched Fly-Ash Tiles for Greener Buildings

Solar photovoltaic (PV) panels that use polycrystalline silicon cells are a promising technique for producing renewable energy, although research on the cells’ efficiency and thermal control is still ongoing. This experimental research aims to investigate a novel way to improve power output and thermal performance by combining solar PV panels with burned fly-ash tiles. Made from burning industrial waste, torched fly ash has special qualities that make it useful for architectural applications. These qualities include better thermal insulation, strengthened structural integrity, and high energy efficiency. Our test setup shows that when solar PV panels are combined with torched fly-ash tiles, power generation rises by 7% and surface temperature decreases by 3% when compared to standard panels. The enhanced PV efficiency is ascribed to the outstanding thermal insulation properties of fly ash tiles and their capacity to control panel temperature. To ensure longevity and safety in building applications, the tiles employed in this study had a water absorption rate of 5.37%, flexural strength of 2.95 N/mm2, and slip resistance at 38 km/h. Furthermore, we find improved structural resilience and lower cooling costs when up to 30% of the sand in floor tiles is replaced with torched fly ash, which makes this method especially appropriate for sustainable buildings. Key performance indicators that show how effective these tiles are in maximizing energy use in buildings include thermal emissivity (0.874), solar reflectance (0.8), and solar absorption (0.256). While supporting more ecofriendly building techniques, this study highlights the advantages of utilizing burned fly ash in solar PV systems: enhanced power generation and thermal comfort. The main results open a greater potential for fly ash use in different building materials. The use of torched fly ash in building materials enhances thermal insulation and structural integrity while lowering cooling costs, making it an ideal choice for eco-friendly construction and highlighting the potential for further research into environmentally responsible, energy-efficient solutions.

A high-safety lithium-ion battery electrospun separator with Si3N4-assisted sulfonated poly(ether ether ketone) for regulating lithium flux

The uncontrolled lithium (Li) dendrite growth significantly impacts the safety performance of polymer separators. To mitigate this growth, this study introduces Si3N4 into sulfonated poly(ether Ether Ketone) (SPEEK) and prepares Si3N4/SPEEK composite separators via electrospinning. At the interface between the Si3N4/SPEEK separator and the Li anode, the Si nanowires that form impede Li dendrite growth, thereby enhancing the electrochemical performance of lithium-ion batteries (LIBs). The Li deposition test of the 10 % Si3N4/SPEEK separator can operate for 1000 h without short-circuiting. Additionally, the LiFePO4||Li cell with the 10 % Si3N4/SPEEK separator shows improved initial discharge capacity (157.8 mAh g−1 at 1C) and superior rate performance (125 mAh g−1 at 10C). Moreover, the nano-scale Si3N4 endows the separator with robust thermal and mechanical properties. The FLIR observations reveal that the 10 % Si3N4/SPEEK separator maintains uniform thermal distribution and structural integrity even at 300 °C, ensuring safe battery operation at high temperatures. The additional load of the 10 % Si3N4/SPEEK separator can reach 10.2 mN, which enhances the puncture resistance of the separator. This work provides a solid approach for the application of SPEEK as a high-safety and high-rate LIB separator.

Thermodynamic analysis and optimization of the TI-PTES based on ORC/OFC with zeotropic mixture working fluids

Thermal Integrated Pumped Thermal Energy Storage (TI-PTES) is a promising technology for large-scale energy storage attributed to the advantages of geographical independence, high efficiency, low cost, and easy coupling with other systems. Little research has been dedicated to TI-PTES based on the organic flash cycle (OFC). This study established thermodynamic analysis of the TI-PTES based on the organic Rankine cycle (ORC) and OFC. The effects of system configurations and key parameters are explored. A multi-objective optimization is introduced to optimize the ORC-TI-PTES, and the P2P efficiency of 57.18 %, exergy efficiency of 37.47 %, and ESD of 4.4 kWh/m3 are achieved. The potential application of zeotropic mixture working fluids in the OFC-TI-PTES is investigated. The DOFC-TI-PTES with [R365mfc(60 wt%) + R1234ze(Z)] shows the best performance among the four OFC configurations. The achieved P2P efficiency and exergy efficiency are 46.66 % and 29.18 %, lower than the ORC-TI-PTES. However, the DOFC-TI-PTES provides an ESD of 11.487 kWh/m3, which is significantly higher than that of the ORC-TI-PTES. ORC-TI-PTES is suitable for energy storage applications that prioritize high thermal and exergy efficiencies, whereas OFC-TI-PTES is suitable for scenarios requiring high ESD.

Comprehensive analysis of waste heat recovery and thermal energy storage integration in air conditioning systems

The proposed work aims to address the challenge of effectively recovering and storing wasted heat in air conditioning (AC) systems, which is crucial for improving energy efficiency and system stability. This study focuses on the comprehensive analysis of a Waste Heat Recovery (WHR) system integrated with Thermal Energy Storage (TES) tanks. A lumped-dynamic thermal model was developed and validated against literature data to accurately simulate the system’s performance. Through a detailed parametric study, the research explores how factors like WHR effectiveness, TES type, PCM type, and TES volume influence the system. The results demonstrate that recovering and storing wasted heat from AC systems significantly enhances operational stability and performance. Notably, increasing WHR effectiveness from 0.55 to 0.85 extends the duration of constant thermal power recovery and also results in higher recovered water temperatures with reduced water pump energy consumption. Furthermore, latent heat storage (PCM tank) extends the duration of stable thermal power recovery by over 61 % compared to sensible storage. Using PCM RT 44HC is more effective for WHR in AC units compared to RT 50 and RT 54HC. Finally, it was shown that increasing PCM tank volume from 2 to 4 m3 improves the duration of constant thermal power recovery by up to 52 % while stabilizing the recovered water temperature.

Double cross-linked chitosan sponge encapsulated with ZrO2/soy protein isolate amyloid fibrils nanoparticles for the fluoride ion removal from water

Fluoride ion pollution in water has become a serious threat to the water environment and human health. Adsorption is a promising means of fluoride removal, but it also faces challenges such as the difficult separation and recovery of powdered particles, the leaching of modified coatings from adsorbents, and the structural disintegration of macroscopic adsorbents. For addressing the above challenges, glutaraldehyde/polyvinyl alcohol co-crosslinked ZrSAF/chitosan spongy composites (ZrS/GPCS) were prepared by utilizing encapsulation strategies and cross-linking. ZrS/GPCS-1, ZrS/GPCS-3 and ZrS/GPCS-4 were prepared due to the different amounts of cross-linking agents. The results showed that their fluoride ion adsorption capacities were 42.02, 44.44 and 39.84 mg/g, respectively. The removal of fluoride ions by ZrS/GPCS was maintained at >80 % in the pH range of 4–10. The addition of glutaraldehyde and polyvinyl alcohol affected the contact efficiency of fluoride ions with chitosan and ZrSAF, influencing the adsorption rate and adsorption effect. Glutaraldehyde, polyvinyl alcohol and ZrSAF improved the thermal stability, mechanical properties and structural integrity of chitosan matrix. Both the chitosan matrix and the internal ZrSAF played an important role in fluoride removal, and the removal mechanisms included electrostatic interaction, hydrogen bonding, and complexation.

Heat Distribution Simulation in a Square Aluminum 7075 Plate Using Laplace Equation and MATLAB

The efficient management of heat transfer from aircraft engines to the wings is vital for maintaining thermal efficiency and structural integrity in modern aircraft design. Excessive heating of the wings, caused by engine-generated heat, can negatively impact aerodynamic performance and safety. This study focuses on analyzing heat distribution in a square aluminum 7075 plate to better understand heat transfer mechanisms. Using the Laplace equation, implemented through MATLAB (2023 Online Version), we aim to simulate and analyze heat distribution on the plate. The numerical method employed in this research involves solving the Laplace equation with Neumann boundary conditions, which represent insulated edges. The Liebmann method is used to iteratively reduce error to less than 1%. Simulations are conducted on an aluminum 7075 plate of dimensions 4x10⁻² m x 4x10⁻² m under various temperature conditions at the edges. Numerical results show that at the 9th iteration, the error reaches 0.71%, while MATLAB simulations yield an error of 0.4681% at the same iteration. The heat distribution across the plate is clearly visualized, and the analysis indicates that increasing the number of grids improves both the clarity and accuracy of the simulation results. In conclusion, this study demonstrates that applying the Laplace equation via MATLAB is an effective approach for analyzing heat distribution in aluminum 7075 plates. The results show that a finer grid resolution enhances accuracy, with a 101-grid system providing particularly clear and precise heat distribution patterns. These findings contribute to the optimization of thermal system designs, especially in aviation-related applications.

Online ultrasonic monitoring of FDM nozzle temperature based on metamaterial buffer rod

Abstract Fused deposition modeling (FDM) has been widely used for fabricating parts with complex geometries. However, during the printing process the nozzle temperature fluctuates which may cause nozzle blockage, inter-filament delamination, over-melting, etc. Therefore, it is of significance to develop an online and in-situ nozzle monitoring system which could overcome such drawbacks for quality assurance. In this work, a multifunctional system is designed by incorporating a traditional ultrasonic probe and a metamaterial buffer rod to online monitor the nozzle temperature and ensure a correct extrusion force and speed. A parametric simulation model is first constructed implicitly based on thermal-acoustic metamaterial structures for the buffer rod. Secondly, since the high-fidelity calculation is computationally expensive, an efficient surrogate model with kriging approach is constructed based on the dataset drawn from limited trials for rapid prediction. Thirdly, multidisciplinary optimization is performed by the NSGA-III algorithm considering the thermal insulation performance, ultrasonic attenuation and structure integrity. The rod is fabricated according to the best parameters decided. A cross-correlation algorithm is calibrated with thermocouple measurement after waveform recording at different temperatures. The online and in-situ temperature measurement can be realized during 3D printing successfully eventually. This will help to improve the printing quality with potential feedback strategies.