Heat Generation Profile Research Articles

Energy dataset of Frontier supercomputer for waste heat recovery

The Hewlett Packard Enterprise–Cray EX Frontier is the world’s first and fastest exascale supercomputer, hosted at the Oak Ridge Leadership Computing Facility in Tennessee, United States. Frontier is a significant electricity consumer, drawing 8–30 MW; this massive energy demand produces significant waste heat, requiring extensive cooling measures. Although harnessing this waste heat for campus heating is a sustainability goal at Oak Ridge National Laboratory (ORNL), the 30 °C–38 °C waste heat temperature poses compatibility issues with standard HVAC systems. Heat pump systems, prevalent in residential settings and some industries, can efficiently upgrade low-quality heat to usable energy for buildings. Thus, heat pump technology powered by renewable electricity offers an efficient, cost-effective solution for substantial waste heat recovery. However, a major challenge is the absence of benchmark data on high-performance computing (HPC) heat generation and waste heat profiles. This paper reports power demand and waste heat measurements from an ORNL HPC data centre, aiming to guide future research on optimizing waste heat recovery in large-scale data centres, especially those of HPC calibre.

Pediococcus spp.-mediated competition interaction within Daqu microbiota determines the temperature formation and metabolic profiles.

Fermented microbiota is critical to the formation of microenvironment and metabolic profiles in spontaneous fermentation. Microorganisms generate a diverse array of metabolites concurrent with the release of heat energy. In the case of Daqu fermentation, the peak temperature exceeded 60°C, forming a typical high-temperature fermentation system known as high-temperature Daqu. However, microorganisms that cause the quality variation in Daqu and how they affect the functional microbiota and microenvironment in the fermentation process are not yet clear. This study adopted high-throughput sequencing and monitored the dynamic fluctuations of metabolites and environmental factors to identify the pivotal microorganism responsible for the alterations in interaction patterns of functional keystone taxa and quality decline in the fermentation system of different operational areas during the in situ fermentation process that had been mainly attributed to operational taxonomic unit (OTU)_22 (Pediococcus acidilactici). Additionally, we used isothermal microcalorimetry, plate inhibition experiments, and in vitro simulation fermentation experiments to explore the impact of Pediococcus spp. on heat generation, microorganisms, and metabolite profiles. Results showed the heat peak generated by Pediococcus spp. was significantly lower than that of Bacillus spp., filamentous fungi, and yeast. In addition, the preferential growth of P. acidilactici strain AA3 would obviously affect other strains to colonize through competition, and its metabolites made a significant impact on filamentous fungi. The addition of P. acidilactici strain AA3 in simulated fermentation would cause the loss of pyrazines and acids in metabolites. These evidences showed that the overgrowth of Pediococcus spp. greatly influenced the formation of high temperatures and compounds in solid-state fermentation systems. Our work illustrated the vital impact of interaction variability mediated by Pediococcus spp. for microbial assembly and metabolites, as well as in forming temperature. These results emphasized the functional role of Daqu microbiota in metabolites and heat production and the importance of cooperation in improving the fermentation quality.IMPORTANCEThe stable and high-quality saccharifying and fermenting starter in traditional solid-state fermentation was the prerequisite for liquor brewing. An imbalance of microbial homeostasis in fermentation can adversely impact production quality. Identification of such critical microorganisms and verifying their associations with other fermentation parameters pose a challenge in a traditional fermentation environment. To enhance the quality of spontaneous fermented products, strategies such as bioaugmentation or the control of harmful microorganisms would be employed. This work started with the differences in high-temperature Daqu metabolites to explore a series of functional microorganisms that could potentially contribute to product disparities, and found that the differences in interactions facilitated directly or indirectly by Pediococcus spp. seriously affected the development of microbial communities and metabolites, as well as the formation of the microenvironment. This study not only identified functional microbiota in Daqu that affected fermentation quality, but also demonstrated how microorganisms interact to affect the fermentation system, which would provide guidance for microbial supervision in the actual production process. Besides, the application of isothermal microcalorimetry in this study was helpful for us to understand the heat production capacity of microorganisms and their adaptability to the environment. This study presented a commendable framework for improving and controlling the quality of traditional fermentation and inspired further investigations in similar systems.

Development and Verification of a Computational Fluid Dynamics Model for a PWR-type Small Modular Reactor Subchannel

With regard to nuclear technology, innovation is critical not only in reducing the current and future costs of deploying Gen III reactors in the short to medium term, but also in enabling the advancement of Gen IV reactors and Small Modular Reactors (SMRs). Considering this aspect, Computational Fluid Dynamics (CFD) can be viewed as an innovative technology for nuclear thermal-hydraulics, increasing the range of possible analyzes with detailed results that are progressively enhanced by advances in processing power, seen in the last decades. This study presents the construction of a CFD model of a subchannel in a pressurized water reactor (PWR) using ANSYS Fluent. The data used for the analysis were obtained from a conceptual design of a Small Modular Reactor, and the development of the model was based on best practice guidelines from existing literature. Turbulence was modeled using the Standard k-ε Model, while a cosine-shaped heat generation profile was used for the fuel. Convergence and mesh studies were conducted to ensure the stability and accuracy of the numerical solution. The results indicated the development of a turbulent profile in the coolant flow, consistent with the inlet conditions. The temperature distribution and pressure drop along the subchannel were also examined. Verification performed by the comparison between the numerical and analytical outcomes revealed low errors. Maximum temperatures in each component remained below the safety limits prescribed for nuclear reactor projects. Based on these results, it can be concluded that the CFD model developed in this study is suitable for thermal-hydraulics analysis of PWR reactors, particularly when examining preliminary assessments of conceptual SMR configurations.

Inference of chemical kinetics and thermodynamic properties from constant-volume combustion of energetic materials

Constant-volume combustion tests have been widely used to characterize the reactivity, the combustion efficiency, and the gas-generating performance of energetic materials. However, the currently used performance metrics (ignition delay time, pressurization rate, and maximum pressure) highly rely on the specific experimental condition, which leads to the challenge of fairly comparing the material performance tested in different conditions and laboratories. For this reason, there has been a need for a new metric independent of the experimental conditions, along with a novel analytical tool. In this work, we proposed a kinetic modeling framework to infer the chemical kinetics and thermodynamic properties from the pressure profiles in constant-volume combustion tests. In this framework, a physical model predicts the thermodynamic states of the system during the constant-volume combustion process, while an inverse model calibrates the model parameters to fit the model to the experimental observation via sensitivity analysis. We demonstrated the success of the framework in inferring the chemical kinetics and thermodynamic properties with both synthesized data and experimental measurements. Moreover, the physical model with the inferred properties enabled a comprehensive understanding of how gas release and temperature rise contribute to the pressure rise in the constant-volume reactor. Therefore, the classical constant-volume combustion experiments can be utilized to infer properties for the design of energetic materials with desired gas and heat generation profiles and for modeling the energetic behaviors in more complex systems.

Design of lithium‐ion battery packs for two‐wheeled electric vehicles

AbstractThe design of lithium‐ion battery pack to meet the power requirements of two‐wheeled electric bikes for Indian conditions is studied here. Theoretical calculations are performed based on the technical data collected from various resources in India. In particular, the two‐wheeled “Activa 6G” vehicle is considered for the analysis. Based on the numerical analysis, a relation between cell parameters such as: C‐rate, voltage, capacity, pack configuration, and vehicle dynamics parameters like: weight of the vehicle, payload, travel range per charge, and energy consumption, has been established. Commercial cylindrical cells, namely: 18650, 21 700, and 26 650 are used in all the calculations. The corresponding battery packs are designed considering a range of 100 km. Furthermore, simulations are performed to understand the voltage‐discharge characteristics, state of charge and variation of cell concentration with respect to time as the battery discharges. The studies are extended to analyze the battery thermal management to estimate the degradation and heat generation rate, and hence, the optimum operating parameters, that is, optimal electrode thicknesses and particle size to enhance the endurance. Based on the degradation and heat generation profiles, the life of the battery pack made of 26 650 cells is found to be better as compared to the battery packs made of 18 650 and 21 700 cells. Furthermore, the analysis is extended for battery packs made of 26 650 cells in four different configurations, considering air and mineral oil as the cooling fluids to estimate the maximum temperature and hence degradation characteristics. Tapered configuration is found to be the best configuration among the four, yielding lowest maximum temperature and capacity fading. On the other hand, when mineral oil is used as the cooling fluid in rectangular configuration, the maximum operating temperature is found to be reduced by 4.49 K. However, usage of mineral oil adds to the periodic maintenance and replacement costs.

Entropy optimization of Marangoni flow of hybrid nanofluid under the influence of viscous dissipation and activation energy: With melting phenomenon

AbstractAs nanotechnology and optimization develop, the demand for more effective and robust heat transfer fluids with much greater thermal conductivities than ordinary ones grows. Marangoni convection is often employed in coloring on the ground, for example, in fine art mechanisms. Melting and welding operations are the most prominent manufacturing uses of the Marangoni convection principle. This article aims to reveal the characteristics of hybrid nanofluid () and nanofluid () under the influence of Margorani convection and Entropy generation in a porous Darcy‐Forchheimer medium under melting circumstances. Viscous dispersion and activation energy's effects are also taken into account. The suggested fluid flow problem is mathematically modeled. A built‐in shooting technique algorithm tackles the dimensionless flow model. After applying suitable transformations, the governing nonlinear PDEs are reduced to highly nonlinear ODEs. The numerical outcomes of obtained ODEs are attained through the bvp4c technique built‐in MATLAB. The effects of various classes of significant parameters on the rate of heat generation and Bejan number profiles are investigated. The physical impact of the flow‐regulating constraint factors is visualized via graphical representations. The results are summarized based on numerical data compared to important engineering formulas such as surface drag force, Sherwood numbers, Nusselt, and density. In terms of final remarks, the main findings are successfully described. This article delves further into the uses of hybrid nanofluids in the primary study regions of medicine, space, ships, and defense. Some of these research areas include the automotive industry, heat exchangers coolant in machining, heat pipes, and manufacturing, electronic cooling, refrigeration, solar energy as well as applications for ventilation, heating, and air conditioning, nuclear system cooling, generator cooling, transformer cooling, and electronic cooling.

Transient Three-Dimensional Thermal Simulation of a Fin Field-Effect Transistor With Electron–Phonon Heat Generation, Three Phonon Scattering, and Drift With Periodic Switching

Abstract The International Roadmap for Devices and Systems shows Fin field-effect transistor (FET) array transistors as the mainstream structure for logic devices. Traditional methods of Fourier heat transfer analysis that are typical of Technology computer-aided design (tcad) software are invalid at the length and time scales associated with these devices. Traditional models for phonon transport modeling have not demonstrated the ability to accurately model three dimensional (3-d), transient transistor thermal responses. An engineering design tool is needed to accurately predict the thermal response of FinFET transistor arrays. The statistical phonon transport model (SPTM) was applied in a 3-d, transient manner to predict nonequilibrium phonon transport in an silicon-on-insulator (SOI)-FinFET array transistor with a 60 nm long fin and a 20 nm channel length. A heat generation profile from electron–phonon scattering was applied in a transient manner to model switching. Simulation results indicated an excess build-up of up to 17% optical phonons giving rise to transient local temperature hot spots of 37 K in the drain region. The local build-up of excess optical phonons in the drain region has implications on performance and reliability. The SPTM is a valid engineering design tool for evaluating the thermal performance of emergent proposed FinFET transistor designs. The phonon fidelity of the SPTM is greater than Monte Carlo and the Boltzmann Transport Equation and the length scale and time scale fidelity of the SPTM is better than direct atomic simulation.

Multi-scale electrochemical thermal model of Electric Double Layer Capacitor under galvanostatic cycling

Electric Double Layer Capacitors (EDLC) have a wide spectrum of application with internal heat generation which may lead to thermal runaway or accelerated aging. This study proposes a multi-scale electrochemical thermal model of EDLCs. Energy equation is solved for cylindrical EDLC device with averaged reversible heat generation rate calculated from local heat generation rate near single carbon nanoparticles derived from first principle. The numerical heat generation and temperature profile resemble experimental results with a prediction error less than 15%. The temperature is uniform across the jelly roll but shows a major drop across the air gap. The reversible heat generation profile is asymmetric and features a sharper peak for exothermic process compared with endothermic process. This is attributed to the relative fast heat dissipation from the EDLC device to the surrounding during exothermic process. Furthermore, detailed contribution of heat generation rate near the electrode/electrolyte interface is analyzed. Negative heat of mixing is observed at the start of charging. This can be attributed to the deviation of flux direction due to the existence of a curved surface. This comprehensive model can be used to study the detailed effect of nanoparticle phenomena on the heat generation and temperature profiles of commercial EDLC devices.

Thermal management of 18650 Li-ion battery using novel fins–PCM–EG composite heat sinks

The present study introduces a novel fin–Phase Change Material (PCM)–Expanded Graphite (EG) composite for better thermal management of a Panasonic NCR18650BD battery at discharge rates higher than its maximum discharge limit 2C. Fins and EG are augmented with PCM to enhance its effective thermal conductivity. Initially, the electrical and thermal behaviors of the battery are simulated for 0.5, 1, and 2C discharge rates using the Newman P2D model, and these are validated against in-house experiments. Following this, the heat generation profiles are estimated from the numerical model to mimic the battery with a heater in the experiments conducted to propose an effective thermal management system for 2, 3, and 4C discharge rates. Three heat sinks, one sans fins, and the other two with 130 and 260 fins, respectively, are considered to perform experiments. Phase Change Material (PCM) named Eicosane (Ei) with an addition of 0, 10, 20, 25, and 30% weight fractions of EG is filled in the heat sinks to study the effect of composite PCM on the thermal regulation of the battery. The heat sink having 260 fins filled with 70% Ei - 30% EG composite outperforms the other heat sinks considered in this study by recording lower temperatures to the extent of 17.5, 20.5, and 22.7 °C than a plain heat sink filled with 100% Eicosane for discharge rates 2, 3, and 4C, respectively. Furthermore, with the addition of 30% EG by volume, the maximum thermal performance of heat sink having 130 fins surpasses the heat sink having 260 fins filled with pure Eicosane by recording 1.3, 0.5, and 1.5 °C lower temperatures for discharge rates 2, 3, and 4C, respectively. In view of this, a possible engineering solution is to employ a simple heat sink, having fewer fins filled with PCM–EG composite instead of intricate heat sinks, having more fins filled only with the baseline PCM, to overcome the design difficulties and manufacturing costs.

Design and Analysis of Control Strategy for an Efficient Battery Thermal Management System of an Electric Vehicle

Lithium-ion batteries (LIB) are being widely used as energy storage systems for Electric and Hybrid Electric Vehicles. The LIBs are particularly sensitive to temperatures and uncontrolled heating may lead to thermal runaway hence, a battery thermal management system is required to prevent the thermal abuse of the batteries. An efficient battery thermal management system ensures that the battery is working in its optimal temperature range thus, increasing its cycle life and performance. In this study, the heat generation profiles have been calculated for various drive cycles namely, US06, FTP-75, and UDDS, which were validated by a thermo-electric mathematical model in MATLAB Simscape. It was found that a cooling plate with an S-channel design is the most suitable for heat exchange applications and a mass flow rate value of 0.4 kg/s gives an optimum compromise between the heat transfer and the back pressure developed. The control strategy proposed in this research work regulates the battery temperature within the specified limit keeping the parasitic power at a minimum.

Research of the two-circuit combined-cycle cogeneration plant’s behavior according to the temperature chart

THE PURPOSE. To consider the actual problem of determining the optimum value of the connected heat load to the cogeneration combined cycle gas turbine (CCGT) of the heat generation profile. METHHODS. Simulation modeling of operation modes using the "United Cycle" software is applied as a research method of the considered power unit operation. We studied several regimes of heat supply from the considered CCGTs during the heating period with the determination of integral annual indicators, as well as the relative fuel savings compared to the separate generation and the increase in the specific integral economic effect for different values of the cogeneration coefficient.RESULTS. We found that the optimal cogeneration coefficient for the object of study is 0.49. However, the value of the optimal cogeneration coefficient, determined by the condition of maximizing the specific integral economic effect for the object of research, is also 0.49. CONCLUSION. Determining the optimal unit commitment, which influences not only the initial investment, but also the expected operating (fuel) costs, is a pressing issue in power plant design. We present a basis for the possibility of using the indicator of relative fuel economy compared to separate generation as an optimization criterion. This parameter is widely used for optimization of combined heat and power units under conditions of planned economy. Under current economic conditions, it is possible to obtain a direct link between the incremental net discounted income from combined production and the relative fuel savings. This method can be used to analyze and optimize the mix of CCGT equipment regardless of geographical area, type of power system, energy resources cost, market conditions, as well as the characteristics of the used equipment.

Comparative study of thermoplasmonic effects of gold and silver metal nanoparticle

We investigated the plasmonic heating effect of noble metal nanoparticles in a water environment using the first-principles approach. In this approach, we have solved the heat transfer equation in the steady state to obtain the heat generation and temperature profile corresponding to two different types of metals. Metals exhibited a surface plasmon resonance property in which maximum absorption of light for smaller size nanoparticles is observed, which can be used to heat up the surrounding environment. Inspired by the same, we have simulated the absorption cross section of different sizes of a metal nanosphere and observed the threshold value of the radius below which absorption is dominant. The maximum absorption of light by the nanosphere produces a hotspot, which can be visualized in terms of the electric field distribution plot. This electric field distribution profile of silver and gold metal nanoparticles is computed under the resonance wavelength using the boundary element method The results thus obtained in terms of the optical cross section are compared with those of the numerical model to establish their veracity. These theoretical works aim to further develop the fundamental understanding of the heating mechanism of plasmonic geometries, which can be used in several applications.

Characterization of dissimilar friction stir welded joints of aluminium alloys by simulation and experimentation

The present work “Characterization of dissimilar friction stir welded joints of aluminium alloys by simulation and experimentation” is a combination of simulation and experimental work. In first part of the work friction stir welding (FSW) process is simulated in abacus software and then second part is based on the experimental work of friction stir welded joints of dissimilar aluminium alloys. In abacus, FSW process is well simulated. In this part heat generation profile during FSW is obtained in work-piece as well as in tool. In second part two alloys i.e. AA 5083 and AA 6061 is welded with friction stir welding process. Three process parameters were selected for welding. Three tool rotational speed is selected i.e. 500 rpm, 710 rpm and 900 rpm and one welding speed i.e. 25 mm/min. All the three welded samples were properly machined and different testing samples were prepared. Mechanical and micro-structural properties were studied on the variation of process parameters. From tensile test it can be concluded that with increase in tool rotational speed tensile strength increases. In all cases brittle fracture was observed. From microstructure study fine grains are observed in weld nugget zone.

Study Of Innovative Susceptibility Of Low Potentional Energy Technologies In Ukraine

The article discusses the formation of innovative susceptibility of enterprises to low-potential energy (LPE) technologies, including measures to increase the innovative susceptibility (IS) of enterprises based on a comparative analysis of the levels of comprehensive awareness of production and business entities on the advantages and disadvantages of heliosytem technology of a heat generation profile (HS HGP). The study shows systematization and balancing of general and specific factors that shape the innovative susceptibility of enterprises to low-grade energy technologies. There are calculated indexes for assessing the awareness of the technical, economic and environmental-technological capabilities of technology HS HGP. Presented the scheme of formation and implementation of IS enterprises to the LPE technologies.

An online heat generation estimation method for lithium-ion batteries using dual-temperature measurements

Estimation of heat generation in lithium-ion batteries (LiBs) is critical for enhancing battery performance and safety. Here, we present a method for estimating total heat generation in LiBs based on dual-temperature measurement (DTM) and a two-state thermal model, which is both accurate and fast for online applications. We demonstrate that the algorithm can keep track of the heat generation rate in real-time under scenarios of designed multi-stepwise heat generation profile and regular fast charging processes. Moreover, the algorithm requires no knowledge of the thermal boundary conditions, providing robustness against changes in convection conditions and ambient temperatures. Finally, this method can capture heat generation induced by abnormal exothermic reactions, which could be a useful tool for detection of battery thermal failures.

Guidelines for Reduced-Order Thermal Modeling of Multifinger GaN HEMTs

Abstract The increasing demand for tightly integrated gallium nitride high electron mobility transistors (HEMT) into electronics systems requires accurate thermal evaluation. While these devices exhibit favorable electrical characteristics, the performance and reliability suffer from elevated operating temperatures. Localized device self-heating, with peak channel and die level heat fluxes of the order of 1 MW cm−2 and 1 kW cm−2, respectively, presents a need for thermal management that is reliant on accurate channel temperature predictions. In this publication, a high-fidelity multiphysics modeling approach employing one-way electrothermal coupling is validated against experimental results from Raman thermometry of a 60-finger gallium nitride (GaN) HEMT power amplifier under a set of direct current (DC)-bias conditions. A survey of commonly assumed reduced-order approximations, in the form of numerical and analytical models, are systematically evaluated with comparisons to the peak channel temperature rise of the coupled multiphysics model. Recommendations of modeling assumptions are made relating to heat generation, material properties, and composite layer discretization for numerical and analytical models. The importance of electrothermal coupling is emphasized given the structural and bias condition effect on the heat generation profile. Discretization of the composite layers, with temperature-dependent thermal properties that are physically representative, are also recommended.

Interdependence of Electronic and Thermal Transport in AlxGa1–xN Channel HEMTs

Aluminum gallium nitride (AlGaN) high electron mobility transistors (HEMTs) are candidates for next-generation power conversion and radio frequency (RF) applications. Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> Ga <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1-x</sub> N channel HEMT devices (x = 0.3, x = 0.7) were investigated using multiple in-situ thermal characterization methods and electro-thermal simulation. The thermal conductivity, contact resistivity, and channel mobility were characterized as a function of temperature to understand and compare the heat generation profile and electro-thermal transport within these devices. In contrast to GaN-based HEMTs, the electrical output characteristics of Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.70</sub> Ga <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.30</sub> N channel HEMTs exhibit remarkably lower sensitivity to the ambient temperature rise. Also, during 10kHz pulsed operation, the difference in peak temperature between the AlGaN channel HEMTs and GaN HEMTs reduced significantly.

Electrothermal Characteristics of Delta-Doped $\beta$ -Ga2O3 Metal–Semiconductor Field-Effect Transistors

A 2-D electrothermal model of delta-doped b eta-gallium oxide ( $\beta $ -Ga2O3) metal–semiconductor field-effect transistor (MESFET) is developed by using TCAD Sentaurus to investigate its electrical and thermal characteristics. The temperature and electric field-dependent electron mobility model is incorporated to predict I – V characteristics of the FET, which are in good agreement with the measured I – V characteristics. We investigated the effect of bias voltages on an electric field, a current path, a volumetric heat generation profile, and a peak temperature at a given total heat dissipation. The peak temperature is observed to be significantly different at the same power dissipation but different bias conditions, e.g., the peak temperature is ~9 K higher when the drain-to-source voltage ( V ds) = 25 V and the gate-to-source voltage ( V gs) = −6 V compared with V ds = 8.3 V and V gs = 2 V at the total power dissipation of 1.16 W/mm. This difference is attributed to the change in the electron Joule heating profile with the applied bias voltage. The effects of the location of the delta-doping layer, the gate–drain spacing, and the source–drain spacing are investigated to guide a future device fabrication. The variation in these parameters mainly affects electrical characteristics such as ON-resistance, saturation current, threshold voltage, and so on. The thermal characteristics, such as peak temperature, temperature profile, and so on, are not significantly affected at a low-power dissipation.

Modeling, cross-validation, and optimization of a shipboard integrated energy system cooling network

This work presents the modeling, cross-validation, and thermodynamic optimization of a shipboard integrated energy system (IES) cooling network to assess (1) the practicality of a dimensionless graph-based model for scalability; (2) the reliability of different statistical metrics in cross-validation; and (3) the effects of design and operational parameters on the system thermal performance. The IES comprised two 2.5 MW induction motors representing a ship propulsion system which operated at various torques over time resulting in different heat generation profiles. A dimensionless first-law graph-based model was formulated with the lumped capacitance approach, and the unknown physical parameters were estimated using the ant colony optimizer with three different calibration metrics. The validated model was used to distribute the total heat exchanger inventory N optimally across the IES by minimizing the peak system temperature. Subsequently, the study demonstrated the robustness of the optimal heat exchanger area allocation against N and the 20× reduction in N with a tenfold increase in the motor cooling power.

Magnetohydrodynamic and thermal analysis of PbLi flows in poloidal channels with flow channel insert for the EU-DCLL blanket

Magnetohydrodynamic (MHD) processes are known to be critically important for the dual coolant lithium lead (DCLL) breeding blanket (BB) concept. In order to minimize the MHD pressure drop in the European DCLL blanket design, the liquid metal breeder (PbLi) is decoupled electrically from the ferritic–martensitic structure (EUROFER) using insulating ceramic-based flow channel inserts (FCIs). The impact of the FCI on the velocity profile and the pressure drop in the DCLL front poloidal channels is studied. Two-dimensional momentum and induction equations for fully developed flows are solved numerically using the ANSYS-Fluent simulation platform under DCLL-relevant conditions (, ). Velocity and pressure drop in the PbLi flows have been computed first for a channel without FCI and then for three possible alumina-based FCI design: two types of sandwich FCI and one naked FCI. In order to analyze thermal effects in the blanket, the obtained velocity profiles are used as inputs to solve the 3D energy equation. The computations of the temperature distribution in the DCLL poloidal front channel with a prototypical exponentially varying heat generation profile are obtained using convective boundary conditions. Results show the effect of the FCI and MHD phenomena on heat transfer.