Search

The design of sport buildings has great impact on top-sport as well as on recreational sport-activities. It implies challenging tasks in meeting the performance-requirements. This includes the control of factors like daylight/lighting, air flow, thermal conditions, just to name a few. Such factors impact the performance of athletes and are hard to control in large sport halls; their control is even harder when the public/audience is located within the halls and require different climate conditions. While mechanical installations are often needed during competitions in order to guarantee constant conditions, relaying on mechanical installations during the daily and recreational use of the venues challenges their medium/long term sustainability. Computational form finding approaches can favour the achievement of high-performing and sustainable sport buildings. In this light, the paper tackles the use of Multi-objective and Multidisciplinary design optimization. The paper presents the concept of Multi-objective Multidisciplinary design optimization techniques to support trade-off decisions between multiple conflicting design objectives and interdisciplinary design methodology, during the conceptual design of sport buildings. The proposed method is based on parametric modelling, performance simulation tools and algorithms for computational optimization, for which the paper tackles three specific aspects. First of all, due to the complexity of large sport buildings, the formulation of the optimization and the screening of the related design variables is crucial in order to obtain a meaningful design space, which helps reducing unnecessary computational burden. Secondly, assessing performance based on measurements and analyses is crucial and can be supported by performance simulations tools; however effectively integrating performance simulations tools in the early phase of the design requires new tools. In this light, a customized computational process for the rapid assessment of temperature and airflow patterns is presented. Thirdly, the process requires the combination of design optimization and design exploration, while searching for well-performing solutions. The importance of design exploration is emphasized also for sub-optimal solutions. In order to facilitate the design exploration, the combination of optimization algorithms, multi-variate analysis algorithms and options for exploring design solutions via an interactive dashboard connected to a database are presented. To exemplify the method, specific case studies are developed as collaboration between Delft university of Technology and South China university of Technology. [ABSTRACT FROM AUTHOR]

This paper is focusing on a numerical investigation of hydrogen Active Magnetic Regenerative Liquefier (AMRL). For this purpose, two-dimensional transient numerical modeling with finite volume method has been developed (i.e. CFD method) to simulate the parallel plane plate (PPP) AMRL regenerators type in order to predict and investigate its thermal performances. The resulting mathematical model has been implanted in ANSYS-Fluent software to overcome the complexity of the Active Magnetic Regenerative (AMR) cycle. To run the simulations, a six cascade-stages hydrogen AMRL cycle has been proposed. From the first to the last stage, the regenerators are made of the following magnetic materials: Gd, Tb, Dy, Ho, Er and Tm respectively. The validity of the proposed model has been performed through Cristal2 AMR demonstrator built to operate at room temperature. Good agreements have been found between experimental and numerical results. Then, simulations of the proposed multistage hydrogen AMRL have been carried out for applied magnetic induction up to 7 T. It has been shown that a mass flow rate of 100 mg s−1 of hydrogen initially at 300 K and 1 atm can be cooled down to 57 K. Thus, the capability of the proposed CFD method for predicting consistent results has been demonstrated. • An unsteady 2D CFD method has been developed for performance predictions of an AMR cycle. • The proposed CFD method takes into account of temperature dependency of AMR cycle's key properties. • The validity of the CFD method has been performed through Cristal2 AMR demonstrator. • Based on AMR cycle, a multistage hydrogen liquefier operating in the range 300–57 K has been investigated. [ABSTRACT FROM AUTHOR]

In the framework of the French Research Agency program “Entrepôts et lieux de stockage dans le monde gréco-romain antique”, a multidisciplinary study on the archaeological, historical, constructive and architectural characteristics of Ostia and Portus’ warehouses is ongoing. The final aim of the project is to understand the role these warehouses played in the process of storage and distribution of food supplies. The starting point is the study of the degree of knowledge the ancient people had in storage techniques. Numerical predictive computational models, supported by in situ measurements to characterize dimension, geometry and materials, are in this paper considered as essential “tools” for the historical, archaeological and functional interpretation of the roman store buildings. In this paper, different hypotheses of the architecture of Portus’ store buildings are analysed and compared using computer fluid-dynamic models in order to support archaeologists in their effort to better understand how ancient warehouses were built, managed and used. [ABSTRACT FROM AUTHOR]

This paper presents the thermal analysis of the underground transmission line, planned to be installed in one of the Polish power plants. The computations are performed by using the Finite Element Method (FEM) code, developed by the authors. The paper considers a system of three power cables arranged in flat (in-line) formation. The cable line is buried in the multilayered soil. The soil layers characteristic and thermal properties are determined from geological measurements. Different conditions of cable bedding are analyzed including power cables placement in the FTB or direct burial in a mother ground. The cable line burial depth, measured from the ground level, varies from 1 m to 2.5 m. Additionally, to include the effect of dry zones formation on the temperature distribution in cable line and surroundings, soil and FTB thermal conductivities are considered as a temperature-dependent. The proposed approach for determining the temperature-dependent thermal conductivity of soil layers is discussed in detail. The FEM simulation results are also compared with the results of the simulation that consider soil layers as homogeneous materials. Therefore, thermal conductivity is assumed to be constant for each layer. The results obtained by using the FEM code, developed by the authors, are compared with the results of ANSYS simulations, and a good agreement was found. [ABSTRACT FROM AUTHOR]

This paper describes the CoolEmAll project and its approach for modeling and simulating energy-efficient and thermal-aware data centers. The aim of the project was to address energy-thermal efficiency of data centers by combining the optimization of IT, cooling and workload management. This paper provides a complete data center model considering the workload profiles, the applications profiling, the power model and a cooling model. Different energy efficiency metrics are proposed and various resource management and scheduling policies are presented. The proposed strategies are validated through simulation at different levels of a data center. [ABSTRACT FROM AUTHOR]

Vibration based structural health monitoring methods often use the changes in the modal parameters to identify damage. However, the modal parameters are not only influenced by damage but also by environmental factors including thermal and humidity conditions. The environmental effects can be large enough to mask the changes caused by damage, especially in the bridge structures that are always exposed to environmental elements. In this paper, a simulation study is conducted to examine the variations in the modal frequencies of concrete box girder and T-beam bridge structures caused by the ambient temperature, solar irradiance and wind speed, utilizing the environmental data recorded at a site in North Carolina, USA. The study includes the effects of temperature dependent material modulus, thermal gradients and prestressing effects on the modal frequencies. Like the environmental temperature variations, the bridge temperatures and model frequencies variations have strong yearly (seasonal) and diurnal trends. The study provides temperature–frequency data at hourly intervals for each bridge structure for future studies and the companion paper where, recognizing the observed seasonal and diurnal trends, the models are proposed to estimate frequencies across seasons from the measured temperature values of a bridge structure. [ABSTRACT FROM AUTHOR]

In this article, first the design procedure of the thermal model of a EDLC type wound capacitor (Electrochemical double layer capacitor) is described, whereby the main objective of modeling is achievement of a very close accordance of simulation results compared to measurements in various operating conditions. Development process is supported by the mathematical analysis of the internal structure of EDLC. Based on the requirements on high degree of model's accuracy, three alternatives of model's complexity are shown. Instead of accuracy the proper model has to fulfill also requirement on the computation time. Next, to meet further demands of complex modeling of supercapacitor modules, mentioned abilities (accuracy of simulation results and fast computation time of solution) must be as lowest as possible. The second important aim of this paper is the description of the development procedure of thermal simulation model of EDLC module (multi-cell supercapacitor system). Consequently simplifications targeting lowest simulation time with achievement of high model's accuracy are provided. At the end of the paper, reader is able to find simulation experiments which are confirming the proposed design procedure. [ABSTRACT FROM AUTHOR]

we presented a new thermal aberration compensation solution based on the cascaded multi-crystal system(CMCS) for the laser system. Different from traditional thermal aberration compensation system, the low-cost, compact CMCS could be applied for the small-beam-aperture aberration correction in the high power laser. The CMCS consists of three units including positive defocus unit, negative defocus and astigmatism unit. Each unit can produce one kind of specific aberration. In this paper, based on the thermal effects in the laser crystal, the theoretical simulations on the construction performance of the low order aberrations and the combination aberration are carried out. When a distorted laser beam passes through the CMCS, the low order aberration of the laser beam could be compensated. [ABSTRACT FROM AUTHOR]

Highlights • Detailed radiation model coupled process simulation of fluidized beds. • Combining the advantages of zone method and Aspen Plus. • A case study on a 0.3 MW fluidized bed. • A modest computing demand. Abstract While providing a fast and accurate tool for simulating fluidized beds, the major limitations of classical zero-dimensional ideal reactor models used in process simulations become irreconcilable, such as models built into commercial software (e.g. Aspen Plus®). For example, the limitations of incorporating heat absorption by the water wall and super-heaters and inferring thermal reciprocity between each reactor model/module. This paper proposes a novel modelling approach to address these limitations by incorporating an external model that marries the advantages of the zone method and Aspen Plus to the greatest extent. A steady state operation of a 0.3 MW atmospheric bubbling fluidized-bed combustor test rig was simulated using the developed modelling approach and the results were compared with experimental data. The comparison showed that the predictions were in agreement with the measurements. Further improvement is to be expected through incorporating more realistic zoned geometry and more complex reaction mechanisms. In addition, the developed model has a relatively modest computing demand and hence demonstrates its potential to be incorporated into process simulations of a whole power plant. [ABSTRACT FROM AUTHOR]

This paper reports on the design, simulation, fabrication and characterization of a bio-inspired angular accelerometer. The sensor mimics the semicircular canals in mammalian vestibular systems. The device pairs a fluid-filled microtorus with a thermal detection principle based on thermal convection. The microtorus is intersected by a set of heaters surrounded with temperature detectors on either side, which sense a temperature profile asymmetry upon applied angular acceleration. The device fabrication is based on a two-mask process. Proper arrangement of four resistive temperature sensors in a Wheatstone bridge reduces the impact of heater-induced buoyancy effects. The toroidal microchannel results in inherent geometric linear acceleration insensitivity. The sensor demonstrates a sensitivity of 124 μV/deg/s 2 for in-plane angular acceleration, two orders of magnitude suppression of cross-axis angular accelerations, three orders of magnitude suppression of linear accelerations, and a test setup limited dynamic range of ±2000 deg/s 2 at 1 Hz. [ABSTRACT FROM AUTHOR]

The output performance of solar array on near-space airship can be effectively improved by the layout optimization of solar array. This paper studied the effect of layout parameters on output energy of solar array on the airship with and without thermal effect, and particularly the optimization of solar array layout under the thermal effect. Based on the thermal model of solar array and the layout optimization model, a Matlab numerical program is adopted to calculate the output power or energy of solar array and latitudes and the change trend of optimum layout parameters for whole year and different latitude. The theoretical model is clearly verified comparing with the experimental result of temperature distribution of solar array. The effect of layout parameter on the thermal performance of airship was then analyzed by CFD simulation. The results show that the output performance of solar array is significantly improved through optimized layout and the output power or energy is decreased when considering thermal effect. The optimization of layout parameter may increase average temperature of airship and the velocity of internal helium of airship. Therefore, it is valuable to investigate the thermal effect of solar array in practical engineering of solar power system. [ABSTRACT FROM AUTHOR]

This paper assesses the thermal performance of an office building with an intermittent occupancy pattern, designed according to three construction scenarios. Annual simulations are carried out using TRNSYS software considering a Typical Meteorological Year (TMY) of six Moroccan cities referring to the representative zones of the recent Moroccan climatic zoning. The energetic and environmental performance of various passive energy efficiency measures are evaluated and discussed. The major finding of this work is that these energy measures can have a positive influence on reducing carbon footprint of the considered building. Annual loads can be reduced by about 20% in Agadir, 48% in Tangier, 53% in Fez 56% in Ifrane, 31% in Marrakech and 41% in Er-rachidia. [ABSTRACT FROM AUTHOR]

This paper presents an efficient finite element procedure for the prediction of welding-induced residual stresses and distortions in large structures. It is based on a prescribed temperature approach using some features of an Abaqus extension called Abaqus Welding Interface to significantly improve the computational efficiency and speed up the normally time-consuming and cumbersome welding analysis setup performed by the user. To validate the temperature and residual stress solutions obtained by the presented method, two numerical examples are analyzed. Comparison is made with the experimental measurements and the results obtained by the heat generation rate approach using the element birth and death technique. The first example is a butt-welding of two plates, while the second is a T-joint fillet welding of two plates. The results obtained by the proposed procedure demonstrate a good agreement in comparison with the heat generation rate approach as well as the experimental measurements. Furthermore, the computational efficiency is remarkably improved compared to the heat generation rate approach as the CPU time is reduced up to ~70% in both examples. [ABSTRACT FROM AUTHOR]

This paper investigates the efficiency of a naturally ventilated double-skin façade (DSF) built in a test cell focusing on the airflow and heat convection of the cavity formed by DSF. The study covers measurements of the test cell and their numerical simulation. DSFs have been widely researched worldwide, since they contribute to the thermal performance of the internal environment and to energy savings by eliminating mechanical conditioning systems. For data acquisition, type K surface thermocouples are installed on the wall faces of the test cell and the additional façade, that is, on the inner and outer face of the wall of the test cell and the inner face of the external one. Furthermore, hot wire anemometers are positioned so as to obtain the air velocity in the lower and upper openings of the cavity, which has an air layer thickness of 0.1 m. The results show that the DSF presence contributes to a decrease of the temperature inside the environment because it inhibits the direct solar radiation. Measurement of the faces shows that at 4:00 p.m. the temperature reaches their maximum values. These values are equal to 25.6   °C on the inner face of the façade and 23.6   °C on the inner face of the test cell, while the outdoor temperature presents values equal to 23.1   °C at this time. [ABSTRACT FROM AUTHOR]

This paper addresses the influence of the transversal and longitudinal parameters in the performance of a small scale linear Fresnel reflector (SSLFR) without longitudinal movement. The main purpose of this study is to show the influence of the design parameters (receiver height, mirror length, and mirror width) on the energy absorbed by the absorber tube. In addition, the influence of these parameters on the shading of the absorber tube is also analysed. Different configurations are analysed regarding the longitudinal angle that the mirrors and the absorber tube form with the horizontal plane. Each of these configurations is analysed considering the optimal length and longitudinal position of the absorber tube. Numerical simulations show the influence of mirror width, mirror length, and receiver height on the energy absorbed. The simulations allow us to analyze the monthly variation of this influence throughout the year, considering also the effect of the latitude. A sensitivity analysis is also carried out in order to evaluate the importance of the parameters. [ABSTRACT FROM AUTHOR]

In hot strip rolling, the work roll shifting method has been widely used to disperse thermal crown and wear of the work rolls in the axial direction. This paper provides a strategic control method for the work roll profile which surpasses the conventional work roll shifting method. A numerical simulation model which enables prediction of thermal crown and wear of work rolls with high accuracy has been developed, and a new shifting method has been proposed, focusing on the problems of the conventional shifting method. In the conventional shifting method, the work roll shift position follows the prearranged pattern, and the work roll profile is not controlled intentionally. On the other hand, in a new work roll shifting method, the work roll profile of all coils in the rolling campaign are predicted by the numerical calculation, and controlled so as to be equal to the target profile by considering the work roll shift position. An evaluation function consisting of the error between predicted work roll profile and the target profile of all coils in the rolling campaign has been used, and the work roll shift position has been decided by the optimum calculation with minimizing the evaluation function. [ABSTRACT FROM AUTHOR]

This paper analyses the numerical convergence and the approximation of the finite element method applied to a biothermal nonlinear model for the bare foot. As far as we know, there is not a previous finite element analysis of this well-known bioheat equation. Thus, this work can be seen as a first step to study the coupling with energy and mass transfer models (water, vapor and gas) at the textiles surrounding the foot. The model is posed as a steady partial differential equation for the temperature field, and a non-linear boundary condition on the external boundary, where heat losses due to convection, radiation and evaporation are considered. The existence and the uniqueness of the solution is proved for the weak formulation and also for its finite element approximation by using arguments of monotone operators. Then, numerical convergence and an a priori error estimates result are obtained. Some numerical simulations are presented to show the accuracy of the numerical method and the behavior of the solution, being qualitatively acceptable and, in some cases, validated against experimentation, being quantitatively correct too. Interesting conclusions are followed from the analysis of the model parameters as well as from the comparison of 2D and 3D solutions. [ABSTRACT FROM AUTHOR]

In this paper, an integrated LED lamp with an electrolytic capacitor-free driver is considered to study the coupling effects of both LED and driver’s degradations on lamp’s lifetime. An electrolytic capacitor-less buck-boost driver is used. The physics of failure (PoF) based electronic thermal simulation is carried out to simulate the lamp’s lifetime in three different scenarios: Scenario 1 considers LED degradation only, Scenario 2 considers the driver degradation only, and Scenario 3 considers both degradations from LED and driver simultaneously. When these two degradations are both considered, the lamp’s lifetime is reduced by about 22% compared to the initial target of 25,000 h. The results of Scenario 1 and 3 are close to each other. Scenario 2 gives erroneous results in terms of luminous flux as the LED’s degradation over time is not taken into consideration. This implies that LED’s degradation must be taken into considerations when LED and driver’s lifetimes are comparable. [ABSTRACT FROM AUTHOR]

In this paper, we present a combined experimental and numerical approach to assess the thermal loads and the cooling mechanism of an internally cooled strut injector for a supersonic combustion ramjet. Infrared measurements of the injector surface are conducted at a moderate external flow temperature. In addition, the main flow field is investigated with the LITA technique. Main features of the cooling mechanism are identified based on experimental data. However, a full evaluation can only be obtained using a complex, conjugate CFD simulation, which couples the external and internal flow fields to the heat conduction inside the injector body. Furthermore, numerical simulations are also presented for hot gas conditions corresponding to combustion experiments. Both hydrogen, which would be used as fuel for flight tests, and air are considered as coolants. While the main features of the cooling mechanism will be shown to remain unchanged, the combustor wall temperature is found to have a significant influence on the cooling. This emphasizes the importance and the usefulness of such complex conjugate numerical simulations. [ABSTRACT FROM AUTHOR]

This paper presents a parametric numerical investigation of solidification around two cooled cylinders placed in tandem under forced convection. The front-tracking/finite difference method is used together with an interpolation technique for solving the phase change process. Evolution of the solidifying interface is followed by the front-tracking, and the interpolation handles the presence of the solid phase and the no-slip and constant isothermal boundary conditions. The effects of various non-dimensional parameters on the evolution of the solid phase such as the Reynolds number Re , the Stefan number St , the dimensionless temperature of the inflowing liquid θ 0 , the ratios of the thermal properties k sl and C psl , and the distance between two cylinders L are studied. The computational results show that the solidified region expands with an increase in k sl or L , or with a decrease in any one of Re, Pr, θ 0 . However, St and C psl have a minor effect on the final form of the solid phase. The effect of density difference between the solid and liquid phases, and results in the case of side-by-side arrangement are also presented. [ABSTRACT FROM AUTHOR]

In selective laser melting, there are two different laser scan pattern including point exposure scan and continuous exposure scan. Different laser scan pattern has a significant effect on the thermal behavior and fluid flow of molten pool. In this paper, under the same energy input, the effects of laser scan pattern on the temperature evolution behavior, molten pool dimensions, fluid flow and cooling rate are thorough studied by method of numerical simulation. Experiments for point exposure are carried out which are in a good agreement with the numerical results. [ABSTRACT FROM AUTHOR]

In this paper, a compact tapered ring monopole (TRM) antenna with high impedance surface (HIS) is reported. This antenna is characterized by improved gain and reduced back lobe radiation. This provides specific absorption rate (SAR) reduction on human tissues, when used in a mobile phone. The reflection phase property of the HIS is used to increase the radiated field towards the antenna, thus providing a good return loss with 21% impedance bandwidth, 7.4 dBi gain and front to back ratio of 21 dB. In contrast to the already reported HIS ground planes, the proposed structure has a simple design methodology with compact form factor of 0.52λ × 0.52λ × 0.026λ at 1.8 GHz. The antenna prototype was fabricated and measurements were carried out. Further, numerical simulations were performed for SAR and thermal analysis. It is observed that SAR and consequent temperature rise in human tissues are greatly reduced, when HIS is added to the TRMA. [ABSTRACT FROM AUTHOR]

This paper outlines the results of the evaluation of the most thermally stressed gas turbine elements, first stage power turbine blades, cooling efficiency. The calculations were implemented using a numerical simulation based on the Finite Element Method. The volume average temperature of the blade and the coefficient of heat transfer from the cooling medium to the cooling channel wall were chosen as the cooling efficiency criteria. A comparison of steam and air used as coolants was done, and the calculations were performed using ANSYS Fluent software. [ABSTRACT FROM AUTHOR]

Safety is the first priority in lithium ion (Li-ion) battery applications. A large portion of electrical and thermal hazards caused by Li-ion battery is associated with short circuit. In this paper, both external and internal short circuit tests are conducted. Li-ion batteries and battery packs of different capacities are used. The results indicate that external short circuit is worse for smaller size batteries due to their higher internal resistances, and this type of short can be well managed by assembling fuses. In internal short circuit tests, higher chance of failure is found on larger capacity batteries. A modified electrochemical–thermal model is proposed, which incorporates an additional heat source from nail site and proves to be successful in depicting temperature changes in batteries. Specifically, the model is able to estimate the occurrence and approximate start time of thermal runaway. Furthermore, the effectiveness of a hydrogel based thermal management system in suppressing thermal abuse and preventing thermal runaway propagation is verified through the external and internal short tests on batteries and battery packs. [ABSTRACT FROM AUTHOR]

The microscopic multiphase flows of thermal inkjet (TIJ) devices usually involve a constantly changing liquid–gas interface. Often the curvature of the interface can become too high at some localized positions to be accurately resolved using a conventional static computational grid. A good solution to such challenging problem is to use the Adaptive-Mesh-Refinement (AMR) method, since AMR technique can concentrate the computational effort in the regions where it is needed most. In recent years, an open-source AMR code, Gerris , has been extensively used and benchmarked for a large variety of surface-tension dominated flows. However, the code cannot be directly used to model the TIJ process due to the lack of bubble dynamics and contact angle model for solid boundaries in the code. Therefore in the paper, we propose the following new approaches to model the TIJ flows and implement these algorithms in Gerris : (1) the vapor bubble is treated as an empty cavity so that its complex behavior of the vapor bubble after the bubble nucleation can be modeled using the adiabatic gas expansion and compression; (2) a height-function method based contact angle model is developed and implemented on the embedded solid surfaces. The new code has been verified and validated through a series of numerical examples and experimental tests. The proposed AMR method and the simulation code can be used in a broad range of applications in TIJ technology as well as multiphase flows of microfluidics. [ABSTRACT FROM AUTHOR]

Ghost imaging with thermal light inevitably has a noise background, which greatly decreases the visibility of the reconstructed image. In this paper we formulate a fundamental equation that the integration of the distribution of any ghost image equals a constant in relation to the coherence of the thermal light source. With this equation we strictly demonstrate that the average visibility of ghost imaging is inversely proportional to its image resolution. In the same time, this inherently inverse relation is verified by our numerical simulation and experimental results. [ABSTRACT FROM AUTHOR]

This paper introduces a Human and Building Interaction Toolkit (HABIT) for simulating the thermally adaptive behaviors and comfort of office occupants alongside building energy consumption. The toolkit uses the Building Controls Virtual Test Bed (BCVTB) to co-simulate a field-tested, agent-based behavior model with an EnergyPlus medium office model. The usefulness of the toolkit is demonstrated through a series of zone and building-level case study simulations that examine the wisdom of pairing local heating and cooling options with strategic thermostat set point offsets, judging from the energy, Indoor Environmental Quality (IEQ), and cost perspectives. Results generally suggest that trading efficient local heating/cooling options for whole space conditioning has both energy and comfort benefits, saving up to 28% of monthly HVAC energy while improving the acceptability of thermal conditions in a Philadelphia climate. Nevertheless, cost analysis shows that the fuel source of conserved energy must be considered – particularly in the case of personal heater use, which adds to electric plug loads and associated utility and CO 2 emissions cost penalties. Moreover, costs from even small changes in simulated occupant productivity tend to overwhelm energy costs, suggesting the need to improve the accuracy and precision of available productivity models across multiple seasons and climates. [ABSTRACT FROM AUTHOR]

Simulation capacity is essential to the engineering design of industrial products with complex functions. This paper discusses a numerical algorithm to simulate the multiscale heat and moisture transfer in the thermal smart clothing system. A group of multiscale nonlinear models are proposed to describe the mix-type coupled heat and moisture transfer in the human body, fabrics, fiber material, and phase change material (PCM) particles. The dynamic thermal boundary conditions among individuals are considered and described to integrate the multiscale models. The coupled partial differential equations of the models are discretized by the finite volume method, and the numerical scheme for the thermal smart clothing simulation are developed considering the specification of wearing scenarios. To validate the models and simulation scheme, the simulation results and experimental results with the same clothing and wearing conditions are compared and discussed. Furthermore, a series of simulation cases are made to present the application of this numerical algorithm in practical design by expressing a sequence of design issues through the simulation results for the designers. This simulation scheme is helpful in the engineering design process of thermal smart clothing to identify the thermal quality of the clothing in advance and thus reduce the design cost. [ABSTRACT FROM AUTHOR]

In this paper, a rural residential model located in Shenyang is established by simulation software DesignBuilder. Simulation process is divided into the following conditions, variety of thermal performance walls, roofs and windows. Building energy consumption was simulated through EnergyPlus under different conditions. The information of EnergyPlus and modelling process are referred. Impact of envelope heat consumption for various thermal performance and the energy saving potential are analysed. This research provides technical support and theoretical guidance for new energy efficient building and renovation projects. [ABSTRACT FROM AUTHOR]

On industrial sites, the promotion of best practices to enable an efficient utilization of energy has emerged as one of the major point of focus. Among the different approaches existing to improve industrial processes, the exergy analysis, although limited to the academic world, has been shown to be a powerful tool for improving energy efficiency of thermal and chemical systems. The purpose of this paper is then to present the use of the ProSimPlus ® modelling and simulation environment as an exergy analysis computer-aided tool. Expressions implemented in the simulator for computing exergies in its various forms are presented. The adopted approach for calculating exergy efficiency in a systematic way is also exposed; it combines the fuel-product concepts to the transit exergy concept. ProsimPlus ® exergy module's capabilities are illustrated through the example of an ammonia production plant. [ABSTRACT FROM AUTHOR]

The interest in stratospheric airships has increased and great progress has been achieved since the late 1990s due to the advancement of modern techniques and the wide range of application demands in military, commercial, and scientific fields. Thermal issues are challenging for stratospheric airships, while there is no systematic review on this aspect found yet. This paper presents a comprehensive literature review on thermal issues of stratospheric airships. The main challenges of thermal issues on stratospheric airships are analyzed. The research activities and results on the main thermal issues are surveyed, including solar radiation models, environmental longwave radiation models, external convective heat transfer, and internal convective heat transfer. Based on the systematic review, guides for thermal model selections are provided, and topics worthy of attention for future research are suggested. [ABSTRACT FROM AUTHOR]

The main objective of the short-term hydrothermal generation scheduling (SHGS) problem is to determine the optimal strategy for hydro and thermal generation in order to minimize the fuel cost of thermal plants while satisfying various operational and physical constraints. Usually, SHGS is assumed for a 1 day or a 1 week planing time horizon. It is viewed as a complex non-linear, non-convex and non-smooth optimization problem considering valve point loading (VPL) effect related to the thermal power plants, transmission loss and other constraints. In this paper, a modified dynamic neighborhood learning based particle swarm optimization (MDNLPSO) is proposed to solve the SHGS problem. In the proposed approach, the particles in swarm are grouped in a number of neighborhoods and every particle learns from any particle which exists in current neighborhood. The neighborhood memberships are changed with a refreshing operation which occurs at refreshing periods. It causes the information exchange to be made with all particles in the swarm. It is found that mentioned improvement increases both of the exploration and exploitation abilities in comparison with the conventional PSO. The presented approach is applied to three different multi-reservoir cascaded hydrothermal test systems. The results are compared with other recently proposed methods. Simulation results clearly show that the MDNLPSO method is capable of obtaining a better solution. [ABSTRACT FROM AUTHOR]

Energy conversion devices undergo thermal loading during their operation as a result of inefficiencies in the energy conversion process. This will eventually lead to degradation and possible failure of the device if the heat generated is not properly managed. The ability to accurately predict the thermal behavior of such a device during the initial developmental stage is an important requirement. However, accurate predictions of critical temperature is challenging due to the variation of heat transfer parameters from one device to another. The ability to determine the model parameters is key to accurately representing the heat transfer in such a device. This paper presents the use of an inverse identification technique to estimate the model parameters of an energy conversion device designed for vehicular applications. To simulate the imperfect contact and the presence of insulating materials in the permanent magnet electric machine, thin material are introduced at the component interface of the numerical model. The proposed inverse identification method is used to estimate the equivalent thermal conductance of the thin material. In addition, the electromagnetic losses generated in the permanent magnet is also derived indirectly from the temperature measurement using the same method. With the thermal properties and input parameters of the numerical model obtained from the inverse identification method, the critical temperature of the device can be predicted more accurately. The deviation between the maximum measured and predicted winding temperature is less than 2.4%. [ABSTRACT FROM AUTHOR]

This paper presents a detailed flexible mathematical model for planar solid oxide fuel cells (SOFCs), which allows the simulation of transient performance characteristics. This mathematical model includes the incorporation of a thermal modelling into an electrochemical model with physico-chemical governing equations and a detailed multi-component gas diffusion mechanism, Dusty Gas Model (DGM). Spatial discretization can be applied up to quasi 3-D geometries and is resolved with the FDM (Finite Difference Method). The model is built and implemented in the commercially available modelling and simulations platform gPROMS™. The model was compared against existing models, the differences in results are identified and attributed to assumptions. Several transient operation case studies are examined such as load change and start-up: the results illustrate how important such a tool is for analyzing SOFC operation. [ABSTRACT FROM AUTHOR]

The arc welding process involves thermal cycles that cause the appearance of undesirable residual stresses. The determination of this thermal cycle is the first step to a thermomechanical analysis that allows the numerical calculation of residual stresses. This study describes the formulation of a 2D finite element with through the thickness parabolic temperature distribution, including an element estabilization procedure. The 2D element described in this paper can be used to perform thermal analysis more economically than 3D elements, especially in plates, because the number of degrees of freedom through the thickness will always be three. A numerical model of a tungsten arc welding (GTAW) setup was made based on published experimental results. Size and distribution of the heat source input, thermal properties dependent on temperature, surface heat losses by convection and latent heat during phase change were considered. In parallel the same setup was modeled using ANSYS software with 3D elements (SOLID70) to compare against 2D numerical results. The results obtained by 2D model, 3D model and experimental data showed good agreement. [ABSTRACT FROM AUTHOR]

This paper proposed a mathematical model and numerical model to investigate the output characteristics of photovoltaic (PV) array of stratospheric airship. In addition, considering with the influence of flight time, flight status,flight location, flight height, environmentaltemperature and other factors on the output power of the PV array, the model ofsolar radiation, and PV array on the surface ofStratospheric Airship are established. Then, the thermal effects of the PV array on the airship is investigated using CFD/Fluent, based on which the three-dimensional temperature profile of PV array and airship are presented. [ABSTRACT FROM AUTHOR]

Blunt nose body with sharp corner is a kind of common configuration for spaceship design. However, for its complexity, there were few valid theories can solve this problem perfectly.In this paper, compressiblenonsimilar boundary-layer analysis and numericalsimulation of Navier-Stokes equationswere used together to give some satisfactory results. The influence of nose radius and corner radius on heating rate over blunt body was also summarized which is very useful for the optimization of thermal protection system. [ABSTRACT FROM AUTHOR]

The focus of this paper is on the thermal environment simulation of engine combustor inner wall in the ground experiment facility. The inner flow and outer flow thermal environment has usually taken place in the inner surface of engine combustor and the outer surface of hypersonic vehicle, respectively. These two kinds of thermal environments have been compared by using the supersonic rectangle Turbulent Flow Duct (TFD) and arc heater.The arc-heated double-models supersonic rectangle TFD experimental technology can commendably simulate the inner flow thermal environment of the engine combustor. The passive, semi-passive and active thermal protection structures of combustor can be tested by this technology for the thousands-scale exposure periods. [ABSTRACT FROM AUTHOR]

Light pipes transmit daylight into building interiors. Their installation into thermally insulated roofs of low energy buildings can be a problem because of thermal bridges and condensation problems. This article is focused on a CFD simulation thermal analysis that includes four variations of light pipes with a segment of a flat roof. Common light pipes with a hollow light guiding tube were compared to special light pipes containing an additional glass unit located inside the tube. The additional glass units increase thermal resistance and reduce condensation risks of the light guiding systems. The light pipes were compared in two different simulation models run in ANSYS Fluent software and the CalA program. Temperature profiles and air flow patterns of the cross sectional profiles of the light pipes served to determine the total heat transmittance and heat losses of the studied light pipes installed in a segment of a thermally insulated flat roof. The paper compares simplified 2D rotational–symmetrical numerical model based on the thermal diffusion equation with the complex 3D CFD numerical simulation. The results confirm that the simplified 2D numerical model is suitable for the thermal evaluation of the light pipes containing an additional glass unit, too. The additional glass unit with the triple glass improves thermal resistance up to 88% in case of light pipe with diameter 600 mm and reduces optical transmittance to 28%. [ABSTRACT FROM AUTHOR]

This paper describes a methodology for the modeling and simulation of a pulsed thermography inspection of carbon fiber-reinforced composites. A thermal–numerical model based on the 3D transient heat conduction equation for heterogeneous media is proposed to model the thermal response of the composite medium when a thermal pulse is applied to its surface. The solution of the model is developed using the finite volume method, in which the approximated equations are obtained by performing energy balances for each elementary volume. The experimental validation of the thermal–numerical model consisted of a comparison of the thermal decay curves for defective areas obtained through numerical simulation and with a pulsed thermography inspection of a laminated composite specimen with simulated defects (Teflon inserts). A parametric study was carried out in order to analyze the influence of the irradiation power density, non-uniform heating and characteristics associated with the defects on quantitative variables such as the onset time and thermal contrast. Numerical results showed that the variable thermal contrast is highly sensitivity to changes in the defect thickness, aspect ratio and parameters related to the external stimulation. Furthermore, an increase in the detectability of defects – especially those with lower aspect ratios – can be achieved by increasing the irradiation power. [ABSTRACT FROM AUTHOR]

Abstract: In this paper we document the relationship between complex flow architecture and global performance for assemblies of heat pumps coupled thermally with the ground through a single U-shaped loop with circulating fluid. The assemblies vary according to heat pump numbers, sizes and locations along the loop. They are classified in a systematic way, and their performance is documented in three classes of designs: assemblies of heat pumps of the same size, heat pumps distributed equidistantly, and large numbers of heat pumps distributed almost continuously on a long loop. The work is based on numerical simulations, and on an analysis that holds in the limit of heat pumps distributed continuously. The relationship between flow architecture and global performance (heat transfer density) serves as guide for the energy design of high-density urban settlements in the future. [Copyright &y& Elsevier]

• Open-source system for integrated simulation of structures in fire. • Coupled CFD analysis with FEM analysis with an automatic HT component. • Allowance for model building in CAD/BIM and transfer into an OpenSees using a GUI. • The HT analysis was validated against recent experimental data and EC predictions. • The Cardington large compartment test used as a demonstration for the integrated system. The collapse of several tall composite buildings over the last two decades has shown that the performance of tall, composite and complex buildings in fire is a necessary design consideration that ought to go beyond simple code compliance. To this end, several advancements in the field of numerical simulation of both the fire and the thermomechanical response of structures have been made. In isolation, the practical benefit of these advancements is limited, and their true potential is only unlocked when the results of those numerical simulations are integrated. This paper starts by showcasing recent developments in the thermal and thermomechanical analysis of structures using OpenSees. Integration of these developments into a unified simulation environment combining fire simulation, heat transfer, and mechanical analysis is then introduced. Finally, a demonstration example based on the large compartment Cardington test is used to showcase the necessity and efficiency of the developed simulation environment for thermomechanical simulation of composite structures in fire. [ABSTRACT FROM AUTHOR]

Abstract: Safety analysis is of ultimate importance for the operation of Nuclear Power Plants (NPP). Experiments even on a pilot scale are quite expensive and therefore numerical simulations play a major role in this analysis. They allow to predict the behaviour of NPP systems under different operational and accident conditions and to develop proper action plans for minimizing the risks of accidents, and minimizing the consequences of possible accidents. For a proper risk assessment and development of emergency plans, a very large number of scenarios have to be simulated, achieving acceptable accuracy for the critical parameters, such as radioactive pollution and temperature. The existing software tools are either very simplistic and therefore quite inaccurate or they use general CFD codes that makes them very slow. This paper presents a customized algorithm and corresponding software tools for simulation of non-isothermal flows in the containment pool of a NPP. It first summarizes the requirements for such simulation tools and then presents the new algorithm which, in the opinion of the authors, is a proper compromise between accuracy and efficiency for solving such problems. It uses a Fictitious Domain Method (FDM) to impose the boundary conditions, a Cartesian finite volume discretization combined with a Domain Decomposition (DD) technique, and a factorized perturbation of the incompressibility constraint proposed recently in Guermond and Minev (2010). Finally, results from numerical simulations in idealized and realistic geometries are presented and discussed. [Copyright &y& Elsevier]

Design and sizing of lithium-ion battery is a challenging task because of inherent multiphysical and multiscale nature of this battery type. Detailed mechanistic models have been developed to resolve the design effects on physico-chemical processes taking place inside the battery and in turn, on battery performance. However, such models are hold back by their mathematically complexity and associated computational cost. In this paper, we come up with efficient design guidelines for Li-ion battery while addressing these model complexities. In essence, we carry out scale analysis of electrochemical and thermal behaviour of a cylindrical spiral wound Li-ion battery. We secure non-dimensional numbers and scales for the leading-order phenomena of charge, energy and species transport as well as associated heat generation and electrochemical reactions. The scales, in particular, provide quick quantification of variables such as temperature increase, potential losses and state of charge during charge/discharge. We verify reliability of the derived scales by comparing their predictions with the results from numerical simulations of an electrochemical-thermal model of battery. Overall, good agreement between the predictions from scales and simulations is obtained. The non-dimensional numbers and scales – which characterize the cell both thermally and electrochemically – are also discussed from the viewpoint of battery design. [ABSTRACT FROM AUTHOR]

Thermal fluid coupled analysis is essential to enable an accurate temperature prediction in additive manufacturing. However, numerical simulations of this type are time-consuming, due to the high non-linearity, the underlying large mesh size and the small time step constraints. This paper presents a novel adaptive hyper reduction method for speeding up these simulations. The difficulties associated with non-linear terms for model reduction are tackled by designing an adaptive reduced integration domain. The proposed online basis adaptation strategy is based on a combination of a basis mapping, enrichment by local residuals and a gappy basis reconstruction technique. The efficiency of the proposed method will be demonstrated by representative 3D examples of additive manufacturing models, including single-track and multi-track cases. • Novel adaptive hyper reduction method for additive manufacturing. • Efficient online reduced basis and integration domain adaptation. • Application to highly nonlinear and transient thermal fluid analysis. • Significant speed-up is obtained for both 3D single-track and multi-track problems. [ABSTRACT FROM AUTHOR]