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• A comprehensive review on numerical simulations of boiling heat transfer from atomistic to mesoscopic and macroscopic scales is presented. • Critical issues related to nanoscale bubble nucleation mechanisms, pool boiling, and flow boiling are highlighted. • Potential solutions and future research in the field of boiling heat transfer using the MDS, LB and CFD methods are proposed. Boiling is an efficient heat transfer mode with significant potential for thermal management in high-power electronic equipment. However, a comprehensive understanding of the boiling process, which encompasses bubble nucleation, growth, coalescence, slipping, and detachment across various scales, remains challenging. Molecular dynamics simulation, lattice Boltzmann, and computational fluid dynamics methods are popular and powerful tools for investigating boiling heat transfer phenomena at microscopic, mesoscopic, and macroscopic scales. These methods enable researchers to uncover the underlying boiling mechanisms and propose heat transfer enhancement techniques. Therefore, this paper provides a comprehensive review of boiling heat transfer, spanning from atomistic to mesoscopic and macroscopic scales, utilizing these three numerical methods. It addresses critical issues related to nanoscale bubble nucleation mechanisms, pool boiling, and flow boiling, and proposes potential solutions and future researches, supplementing our previous review [Some advances in numerical simulations of multiscale heat transfer problems and particularly for boiling heat transfer, Annu. Rev. Heat Transf., 6 (2022) 217–269]. Besides, by shedding light on the characteristics of these numerical methods in studying boiling heat transfer, this paper aims to foster their development and advance enhanced heat transfer technologies. [ABSTRACT FROM AUTHOR]

• A 3D thermal lattice Boltzmann model for simulating melt flow and heat transfer in CZ single crystal growth has been constructed. • The coordinate system transformation is adopted to extend the application of LBM on 3D cylindrical cavities. • The critical Reynolds numbers are increased by introducing a transverse magnetic field. A three-dimensional (3D) thermal lattice Boltzmann model of crystal growth is presented to study the magneto-hydrodynamics (MHD) mixed convection in the melt of Czochralski silicon single crystal growth in this paper. In order to solve the problem of lattice Boltzmann method's difficulty in solving the flow of 3D cylindrical cavity, the 3D physical model of crystal growth is transformed from the Cartesian coordinate system to the Curvilinear coordinate system. And the irregular grids in the Cartesian coordinate system are transformed into regular grids in the Curvilinear coordinate system to facilitate the establishment of the Lattice Boltzmann model. Under the above operations, two coupled distribution functions are established to solve the governing equations. Two D3Q19 models are adopted to solve the melt velocity and temperature. And the 3D lattice Boltzmann modeling of crystal growth with cylinder boundary is realized by interpolation in Curvilinear coordinate system. The comparison with the experiment and other references proves that the proposed model and boundary treatment scheme is correct and it proposes a new way for studying the 3D crystal growth or other similar 3D cylindrical cavity simulations. Furthermore, the unstable melt flow for two cases are also simulated in this paper and the critical Reynolds number are also obtained. Results show that the introduction of the transverse magnetic field enhances the stability of the crystal growth system and increases the adjustable range of crystal rotation parameter. The obtained conclusion has an important reference for adjusting the process parameters during the CZ crystal growth. [ABSTRACT FROM AUTHOR]

In this paper, fully coupled particle resolved direct numerical simulations are used for heat transfer calculations. For modelling fluid velocity and temperature, the immersed boundary method (IBM) is used. Particle-particle heat transfer is modelled using well-established relations from the literature. Two-way coupling between particles and fluid is obtained using a body force that is a function of the solid volume fraction present in the fluid grid cell. Results are compared with those of spouted bed experiments to validate the simulations, and good agreement is observed. At the end of the paper, several interesting characteristics of spouted bed are obtained using simulations. The speedup of the method used for simulations was tested on multi-core CPU clusters. It is observed that the simulations scales almost linearly with the number of CPUs (tests were done up to 500 CPUs), showing the capability of the particle resolved DNS to be used on multi-CPU architectures. Distribution of particle temperatures by (a) Simulations (b) Experiments at packed bed conditions; Distribution of particle temperatures by (c) Simulations (d) Experiments at spouting condition. [Display omitted] • Heat transfer in spouted bed is modelled using particle resolved DNS. • Simulations results agree well with experiments. • The underlying physics of heat transfer in a spouted bed is studied by simulations. [ABSTRACT FROM AUTHOR]

The packing is the core heat transfer unit in the cooling tower. To improve the heat and mass transfer performance of the counterflow wet cooling tower, a new double S-wave structure packing is proposed in this paper, and its performance in heat-mass exchange is investigated using a combination of numerical simulation and experiment. The flow heat transfer performance of the double S-wave packing with different sheet spacing, tilt angle and inlet area is studied by numerical simulation, and the law of different structural parameters affecting the packing is derived to determine its optimal structure. The thermal and resistance performance of double S-wave packing and conventional double-folded packing under different working conditions were studied in comparison with each other by building an experimental bench. The results show that the cooling efficiency of double S-wave packing is 13.74% higher and the pressure drop is 3.58% lower than that of double-folded packing. The research results can provide important guidance and reference for engineering practice. [ABSTRACT FROM AUTHOR]

• A novel circuit gas gap heat switch (GGHS) is proposed for dilution refrigerators. • The GGHS features interleaved cylindrical walls forming a cavity filled with gas. • Heat transfer characteristics are simulated considering 4He actual gas properties. • Effects of operating and geometrical parameters on GGHS performance are studied. • Experimental results validate the proposed simulation model. The gas gap heat switch (GGHS) used for controlling heat transfer between different stages can be an important component for the precooling process of some dilution refrigerators. In this paper, a novel circuit GGHS is a rotationally symmetric heat switch assembly with annular fin arrangements to strengthen the heat-transferring effect. A numerical model considering 4He actual gas properties is proposed to investigate the heat transfer characteristics in the circuit GGHS, in which the effects of charge pressure, cold end temperature, thickness and length of walls on the mean thermal conductance (MTC) are studied. Simulation results show that the MTC increases with the growing cold end temperature, wall thickness, and length, respectively. Given the pressure of 10 kPa, cold end temperature of 4.2 K, wall thickness of 0.97 mm, and wall height of 66 mm, the theoretical MTC is 0.828 W/K. Experimental results indicate that the proposed simulation model is reasonable. Furthermore, the increment of the MTC decreases with the growing temperature. The GGHS used in experiments had a cold end temperature of 4 K, wall thickness of 0.65 mm, and wall height of 33 mm; the measured MTC was 0.219 W/K. Only when the temperature is above 10 K does the charge pressure have a pronounced effect on the MTC. This study provides helpful theoretical guidance for the design and optimization of the circuit GGHS. [ABSTRACT FROM AUTHOR]

The particle sedimentation and phase change in the mushy zone are accompanied by a variety of complex transfer processes involving momentum, heat, and mass. It is very important to investigate the coupling process of particle settling and melting in the mushy zone for revealing the mechanism of the solid-liquid phase change. In this paper, the motion process and heat transfer characteristics of an elliptic particle as well as two particle interactions in the vertical channel were solved by the finite element method with the consideration of coupling of the phase change and motion. The Arbitrary Lagrangian-Euler Method (ALE) was employed to track the interface of the moving particle and fluid. Results show that the elliptical particle settles along the channel's center line vertically under gravity and undergoes phase change simultaneously. Uneven velocity and temperature fields surrounding the particle are generated by sedimentation, resulting in the particle with an irregular shape. When the initial position of the particle deviates from the center line, the particle deflects during the sedimentation and shifts both left and right in the X -direction. The different initial angles of settling also affect the sedimentation velocity and melting rate. When two particles settle simultaneously, they will lead to complex movement and heat transfer due to the interaction between each other. If the arrangement is eccentric, both particles undergo complex deflections during sedimentation, leading to different melting rates for the two particles. [ABSTRACT FROM AUTHOR]

• This paper reports on calculation of dislocation density in 200 mm SiC crystal grown by PVT method. • Numerical study based on a model was carried out for modeling of dislocation density. • Evolution of crystal growth interfaces were captured using a dynamic mesh technique. Physical vapor transport (PVT) is the dominant method for growing 200 mm SiC crystals, and the crystals produced by this method still have dislocations, which affect the performance of the device. In this study, the finite element analysis of 200 mm SiC crystal growth has been conducted to investigate the influencing parameters on the dislocation density. The calculations are based on the model of multiple resistance heating. The transient heat transfer for the crystal growth is first calculated. A dynamic mesh technique is then employed to consider the shape evolution of the crystal during the growth. Finally, the distributions of the internal stress and dislocation density have been calculated based on the Alexander-Haasen model. The comparison among different parameters provides guidance for reducing the thermal stress and dislocation density in the 200 mm SiC crystal growth. [ABSTRACT FROM AUTHOR]

To optimize the uneven distribution of flow field in the mechanical draft cooling towers, four cases for deflector plates are proposed. Based on the analysis of the velocity and temperature fields in the tower, the effect of the deflector plates to strengthen the local heat transfer is investigated. In addition, the thermal and ventilation performance is investigated with different fan speed and circulating water flow rate. The results show that the arrangement of the deflector plates can guide the ambient air into the inefficient heat transfer region. Of the four cases studied, Case 4 has the optimal performance. Compared with the original tower, the outlet water temperature reduces by 0.22 °C, the cooling efficiency increases by 1.53%, and the Merkel number increases by 6.35%, while the ventilation rate keeps at 699 m3/s. The thermal performance of Case 4 is better than that of the original tower when only the fan speed or the circulating water flow rate are changed, and it is improved with the increase of the fan speed and the decrease of the circulating water flow rate. This paper can guide the optimization of enhanced local heat transfer in mechanical draft cooling towers. • A numerical model of a mechanical draft cooling tower is developed. • The model can be used for local heat transfer enhancement studies. • Deflector channels are created by the action of the deflector plates. • Regions with lower heat transfer efficiency are optimized. • Utilizing deflector plates exhibits the capacity to enhance the thermal efficiency. [ABSTRACT FROM AUTHOR]

• Normal mode stability analysis performed on counjugate heat transfer (CHT) 1D problem. • Stability analysis reveals existence of lower stability bound for coupling coefficient in Robin-Dirichlet interface boundary conditions. • Validity of stability analysis results is verified empirically. • Stability analysis is extended to more general CHT problems. This paper aims to evaluate and validate a mathematical coupling model, based on a normal mode stability analysis, for steady conjugate heat transfer problems. In order to achieve this goal, an aerothermal computational code was designed specifically ex novo to meet the needs of the current study. A large number of numerical simulations were carried out within the framework of the Dirichlet-Robin fluid-solid interface procedure and with conditions strictly identical to those adopted in the mathematical model. These coupled computations have been synthesized in five representative cases. The computed results show that the stability limit and the numerical Biot number derived from the coupling model are very reliable parameters. Many other physical and numerical aspects, such as the splitting of the coupling period are also considered in this work from which some interesting and promising results are obtained. At the end of this paper, we assess the general potential, limits and constraints of the mathematical model and its extension to multidimensional cases is discussed. [ABSTRACT FROM AUTHOR]

Workers exposed to hot environment experiences physiological changes, implicating human health and occupational safety. Phase change material (PCM) cooling vest is effective for personal cooling and thermal comfort. In this paper, the human-PCM-clothing model was constructed by combining the bioheat model and the PCM-clothing model to predict the cooling effect of PCM on thermal response in hot environments. The multi-segmented human bioheat model considered the effects of high temperature on metabolic rate, blood flow rate, and dehydration on the sweating rate. The PCM-clothing model analyzed heat and mass transfer between the PCM and its thermal environment. The model was tested with published data and the relative errors between the simulated and measured results were below 2.2% for mean skin and 0.33% for core temperature. The numerical parametric study was investigated to study the effects of the melting temperature and latent heat of the PCM packages on heat transfer. PCM with high latent heat and appropriate melting temperatures benefits body cooling performance. The equation for the optimum solution corresponding to the latent heat of PCM at different melting temperatures was derived. This study can guide the choice of PCM packages and the human thermal response analysis in a hot environment. • The human-PCM-clothing model was established to predict the cooling effect of PCM. • Multi-segmented bioheat model was improved for workers working in a hot environment. • PCM clothing model for heat and mass transfer between different layers was proposed. • The optimum latent heat for different melting temperatures of PCM was obtained. [ABSTRACT FROM AUTHOR]

LBE HCOTSG, which combines the benefits of lead‑bismuth eutectic (LBE) and helical coil once-through tube steam generator (HCOTSG), has the potential to be an excellent heat exchanger choice. Given the similarity of the structure, the analysis of cross/oblique bundle flow heat transfer can help reveal the heat transfer characteristics of the HCOTSG shell side. In this paper, a numerical method for LBE in cross/oblique bundle flow is proposed. Based on the validated method, the application range of the correlation on the flow of the LBE cross/oblique bundle obtained from experiments is broadened based on the numerical simulation work. The influence of tube geometric arrangement in the bundle is also taken into account, including the inclination angle (θ), S min / d, and various staggered arrangements. The difference between numerical simulation results and experimental data is less than 15%. For LBE cross/oblique bundle flow, the extended correlation taking geometric parameters into account also has good applicability. The alternating inclination angle arrangement at an angle of 8° can greatly enhance heat transmission efficacy by up to 33%. The impact of geometric arrangement is estimated in relation to local temperature. This work provides a correlation for the flow of the LBE cross/oblique bundle that is more broadly applicable. Furthermore, this work will significantly benefit the design optimization and program development of LBE HCOTSG or other innovative heat exchangers with cross flow of LBE. • A numerical method for LBE cross/oblique bundle flow is proposed and validated. • The application range of the correlation is broadened based on the method. • Heat transfer performance of LBE flow cross tube bundle is numerically studied. [ABSTRACT FROM AUTHOR]

In the present paper the behaviour of human cardiac tissue during cryo-ablation is simulated with a finite difference algorithm which solves the Pennes' equation including the phase change during freezing of the cardiac tissues. The evolution of temperatures at different points is calculated and the movement of the ice front is obtained from simulation results. All phenomena related to heat transfer in living tissue are considered: heat conduction, heat release and absorption due to heat capacity, metabolism and blood perfusion. Although the geometry and the assumed boundary conditions are quite simple, the structure of the developed model can be easily adapted to more complex geometries. Model results show for instance that with a power of 10 W tissues distant 0.5 mm from the probe are ablated, while the other tissues more than 0.5 mm remain at −20 °C, so undamaged The results also show that the outcome of cryo-ablation treatment depends on many parameters: operational parameters such as the power heat absorbed by the probe (i.e. the mass flow rate of the cryo-fluid) and the duration of therapy application; biothermal parameters such as metabolic heat flux and blood perfusion; thermophysical properties of the tissue. Among these the effects of both blood perfusion and metabolic rate result less influencing. The numerical model presented could be useful to estimate the best conditions for the application of the probe during treatment and the possible change of the cure parameters to adapt the therapy to different patients. [ABSTRACT FROM AUTHOR]

Under the influences of the chimney effect and longitudinal ventilation, the risks of continuous spill fires in inclined tunnels are catastrophic with great complexity and uncertainty. In this paper, the spread and combustion behaviour of a continuous spill fire under the effect of longitudinal ventilation in an inclined tunnel is studied and compared with that in a horizontal tunnel through fire dynamics simulator (FDS) software. The critical time shrink point (SP) to reach the maximum combustion area (MCA), the change rates of the dimensionless combustion area A * and stable combustion area (SCA), the flame propagation speed, and the dimensionless burning rate W * values and heat transfer mechanisms of the combustion fuel layer, tunnel wall and flame smoke are analysed; the prediction equation between the dimensionless burning rate W * and the dimensionless wind speed V * of the upstream and downstream spill fire are identified. The results show that longitudinal ventilation leads to a nonlinear increase in the MCA, and the longitudinal slope leads to a great decrease in the critical time SP. In the stable combustion stage, the SCA in the downstream spill fire is greater than that in the upstream spill fire. Additionally, there are significant differences in the flame propagation phenomenon of spill fires. On the windward side, the maximum flame propagation speed of the upstream spill fire is 3.8 times that of the downstream spill fire; however, on the leeward side, the maximum flame propagation speed of the upstream spill fire is only 18% of that of the downstream spill fire. According to the prediction equation, with the increase in the dimensionless wind speed V *, the dimensionless burning rate W * decreases gradually; the dimensionless burning rate W * of the upstream spill fire is always greater than that of the downstream spill fire. The increase in thermal feedback caused by the inclined flame is the main reason for the significant difference in the spread of the spill fire in the ventilated inclined tunnel, causing the flame propagation speed of the −10% slope on the leeward side to gradually approach that of the −5% slope. • The spill fire behaviour in inclined tunnel with longitudinal ventilation was studied. • The influence of different wind speed, slope and tunnel inclined direction on the time shrink point (SP) to reach the maximum combustion area, the change rate of dimensionless combustion area and stable combustion area, flame propagation speed, and the dimensionless burning rate of spill fire was studied. • Come up with the prediction equation between the dimensionless burning rate and the dimensionless wind speed of the upstream and downstream spill fire. • The increase of thermal feedback caused by inclined flame is the main reason for the significant difference in the spread law of spill fire in the ventilated inclined tunnel. [ABSTRACT FROM AUTHOR]

• The working medium studied is supercritical liquid hydrogen. • Different from the traditional circular U-tube structure, this paper adopts the triangular U-tube structure for research. • Five different structural types of U-tubes were compared and the one with the best heat transfer performance was selected. • This work provides a useful technical guidance for thermal design and thermal management of neutron source and target station, as well as novel ideas for flow and heat transfer of supercritical liquid hydrogen in U-tube. In this study, the heat transfer characteristics of supercritical hydrogen in triangular U-tubes with different radius were investigated. In order to compare the heat transfer capacity of triangular U-tubes, and to explore the heat transfer characteristics of supercritical liquid hydrogen inside them, a three-dimensional numerical simulation was carried out by Fluent. The unstructured grid and RNG k-ε turbulence model were used to encrypt the grid. Meanwhile, the grid independence and the effectiveness of the turbulence model are verified. The T w , T f and Nu along the triangular U-tube at different q and Re were compared. The result shows that T w , T f and Nu increase with the increase of q and Re. The change of Re was found to be largest for Nu. The effect of secondary flow on Nu was similar to the entrance effect of upstream straight pipe, and the effect of secondary flow on Nu was slightly larger than the entrance effect. This work provides a useful technical guidance for thermal design and thermal management of neutron source and target station, as well as novel ideas for flow and heat transfer of supercritical liquid hydrogen in U-tube. [ABSTRACT FROM AUTHOR]

• Logging Data of Geothermal Well Explain Geothermal Conditions in Xi'an Sag of Weihe Basin. • Field tests show that the short-term single-well heat extraction capacity of the deep coaxial borehole heat exchanger using a vacuum gel steel tube with a thermal conductivity of 0.002 W/(m·K) can reach 2012.37 kW. • Experimental verification of COMSOL coaxial stratified heat transfer model based on stratigraphic age. • The simulation results show that the heat transfer performance of the heat exchanger is better when the inner tube thermal conductivity is lower than 0.3 W/(m·K). The deep coaxial borehole heat exchanger (DCBHE), as an important part of the deep-seated ground heat exchanger system, undertakes the important task of heat exchange with the underground geotechnical body to provide heating for the building. In this paper, through field test, numerical simulation and sensitivity analysis, the influence of thermal insulation performance of inner tube, heat preservation method of inner tube and diameter ratio of inner tube to outer tube on heat extraction capacity of deep coaxial borehole heat exchanger is studied. Field tests in intermittent operation mode (9.5 h operation and 14.5 h shutdown) show that the short-term single-well heat extraction capacity of the deep coaxial borehole heat exchanger using the vacuum gel steel tube with a thermal conductivity of 0.002 W/(m·K) as the inner tube is 574.96 W/m. The simulation results show that the diameter ratio of the inner and outer tubes has little effect on the heat extraction capacity, and the diameter ratio of the inner and outer tubes of 0.65 has the smallest resistance loss along the way. For heat exchanger with depth of 3500 m, the location of severe thermal interference between the inner and outer tubes is mainly located in the upper part of the heat exchanger near the surface, especially in the 1400 m to 2100 m section. The research results can provide a reference for the optimization design of medium-deep coaxial heat exchange buried pipe system and the promotion of medium-deep geothermal energy utilization. [ABSTRACT FROM AUTHOR]

• This paper considers radiation effects on the combined thermo-solutal Marangoni convections in the same direction and opposite directions in a floating half-zone under zero gravity with the transition mode maps proposed. • The thermo-solutal Marangoni convections in the opposite directions behave more complex than those of in the same direction, with multiple structures in the concentration field. • Two sorts of oscillatory rotating modes are observed in the same-direction Marangoni flows under either heat loss or heat gain, while two kinds of stabilizing effects are predicted under heat loss in the opposite-direction Marangoni flows. Numerical simulations of thermo-solutal Marangoni convection in a floating half SiGe zone with radiation effects under zero gravity have been carried out. In this system, thermal and solutal Marangoni flows develop along the melt free surface either in the same direction or opposite directions depending on the directions of thermal and solutal gradients. In present model of a half SiGe zone, the ambient temperature is kept constant. Radiation due to heat loss and heat gain is considered as the dominant heat transfer mechanism from the ambience. Transition mode maps, based on concentration distribution with respect to Marangoni ratio (R σ = M a C / M a T) and ambient temperature (T a), have been developed to investigate the effect of radiation at unequal or equal (Ma C , Ma T) values. The maps reveal the main concentration structures and potential transitions at various T a values. The opposite thermo-solutal Marangoni flows give rise to more complex structures than those of the same-direction flows. Both heat loss and heat gain may alter or destabilize the concentration distribution in the melt. However, to some extent, heat loss in the opposite-direction flow case provides a stabilizing effect on the azimuthal wave pattern at a lower or higher R σ value. [ABSTRACT FROM AUTHOR]

• A new correlation of boiling heat transfer process in helically coiled tube is proposed. • Obtained the distribution law of water and water-vapor two-phase flow in the helically coiled tube under boiling conditions. • The maximum temperature of the inner wall surface of the helically coiled tube appears at the position where the circumferential angle ranges from 120° to 180°. In this paper, the partial geometric models of helically coiled tube type heat exchanger with different tube diameters (d = 12, 19, 25 mm), tube pitches (P = 50, 100, 150 mm) and helical radius (R = 100, 150, 200 mm), were established. Numerical simulation and performance comparison were carried out using water and water vapor as the working fluid. The gas–liquid phase distribution in the helically coiled tube, the gas volume fraction at different cross-sections, and the changes of heat transfer coefficient and pressure drop along the length of the helically coiled tube were analyzed. The results showed that the gas phase was concentrated in the inner side (near the side of the central axis) and the upper side of the helically coiled tube under boiling condition, and the liquid phase was concentrated in the bottom of the helically coiled tube and is stratified with the gas phase. As the helical radius and tube diameters increased, the heat transfer coefficient and unit pressure drop decreased gradually. Based on the simulated data, the boiling heat transfer correlation was fitted by the method of multiple nonlinear regression, and the mean absolute error was 4.5% compared with the modified Chen's correlation. Therefore, the numerical results were correct and trustable. [ABSTRACT FROM AUTHOR]

• The guide vane is added to the air inlet chamber of the intercooler. • An end-to-end model of the intercooler guide vane based on PSO-SVR algorithm. • Structure parameters of guide vane are optimized using genetic algorithm. In order to fundamentally solve the problem of poor air flow uniformity in the cooling pipe of the heavy-duty vehicle intercooler, which leads to poor heat exchange effect, this paper innovatively proposes to add a guide vane in the air chamber of the intercooler. The air flow uniformity in the cooling pipe of the heavy-duty vehicle intercooler is investigated under different structural parameters of guide vane based on the established end-to-end model. In fact, the end-to-end prediction model is innovatively proposed to characterize the relationship between the structural parameters of guide vane and performance parameters without conducting the high-cost and long-term experiments or numerical simulation. Besides, structure parameters of guide vane with the optimal airflow uniformity coefficient are obtained using genetic algorithm (GA), that is, the diversion angle (α) is 18°, the width of rectangular holes in the guide vane (L) is 6 mm and the number of rectangular holes in the guide vane (N) is 3. To demonstrate the effectiveness of the proposed method, the optimized intercooler is validated and it is found that the airflow uniformity coefficient of the optimized intercooler is 0.983, which is 5.25% higher than the original structure, the outlet temperature is reduced by 8.2 °C. [ABSTRACT FROM AUTHOR]

• 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]

pEDFM is a newly developed numerical simulation framework for mass transfer in fractured reservoirs, and this paper aims to study the application of the pEDFM framework to numerical simulation of two-phase heat and mass transfer in fractured reservoirs. Firstly, the finite volume method is used to discretize the mass and energy conservative equations. Then, all the connections between control volumes including two types of fracture-matrix (f-m), three types of fracture-fracture (f-f) and one type of matrix-matrix (m-m) connections are constructed, and corresponding transmissibility formulas of mass and heat transfer in finite-volume discrete schemes for these connections are given, and Newton iteration method is used to solve the fully implicit coupled discrete equations to obtain cell temperature, pressure and water saturation. Finally, two numerical examples including multiphase flow across high-conductivity fractures and flow barriers are implemented to show that pEDFM can eliminate the errors in EDFM for the calculated temperature profiles. An application case that applies waterflooding to a fractured reservoir model with a fractured horizontal well, four water injection wells, natural fractures and a fault is considered to show that, compared with EDFM, pEDFM can more accurately and effectively handle the numerical simulation of mass and heat transfer in realistic fractured reservoirs with complex geological conditions. • EDFM makes large errors in calculating the temperature profiles in some cases. • pEDFM can eliminate much errors in EDFM for calculating temperature profiles. • The low-conductivity "fracture" reduces the nonlinear convergence speed. • The low-conductivity "fracture" increases the condition number of Jacobian matrix. [ABSTRACT FROM AUTHOR]

This paper presents a constitutive model for the simulation of temperature and relative humidity effects on concrete expansion due to Alkali–Silica Reaction (ASR). The model was formulated within the multiphysics framework of the Lattice Discrete Particle Model (LDPM). LDPM simulates concrete internal structure at the mesoscale defined as the length scale of coarse aggregate pieces. As such it accounts for the heterogeneous character of ASR expansion, cracking and damage, creep, hygrothermal deformation as well as moisture transport and heat transfer. The overall framework was calibrated and validated by comparing several numerical simulations with a large database of experimental data gathered from the literature. The proposed model is able to capture accurately all available experimental evidence, including: (a) the increase of expansion rate for increasing temperature and its marked decrease for decreasing relative humidity; and (b) both increase or decrease of ASR ultimate expansion as function of temperature. [ABSTRACT FROM AUTHOR]

• Two different immersed surfaces are studied: a sphere and a vertical cylinder • CPFD properly predicts low heat transfer rates in defluidized regions • TFM approach over predicts heat transfer rate up to 77 % compared to CPFD • Different local heat transfer mechanisms are observed on the heat transfer surface This paper presents a 2-D numerical simulation of a freely bubbling fluidized bed with immersed surfaces, using the Computational Particle Fluid Dynamics (C P F D) model implemented in the Barracuda commercial software. The heat transfer coefficients obtained are compared with an experimental study available in the open literature and numerical simulations based on the two-fluid model approach performed by other authors. Two different immersed surfaces, representing spherical and cylindrical geometries were studied. The simulations results show different heat transfer mechanisms, depending on the angular position in the two immersed surface geometries studied. The time average heat transfer coefficient around the whole heat transfer surface were 25 % and 38 % lower than the experimental study, for the cylindrical and spherical surfaces, respectively. These differences are lower than the results obtained with the two-fluid model approach reported in the open literature. The numerical results indicate that CPFD-Barracuda is able to properly simulate the heat transfer and the dynamics of the bed in defluidized regions, such as on the top of an immersed surface, where the two-fluid model fails and overpredicts the heat transfer rate. [ABSTRACT FROM AUTHOR]

• Experimental and numerical investigation of GLT beams exposed to fire is presented. • The temperature field is recovered using FEM simulation and Bayesian inference. • Parameters of simple charring rate models are improved using Bayesian inference. • Proposed approaches open the door to stochastic analysis of GLT beams loaded by fire. This paper presents a combined experimental and numerical investigation of the behavior of glued laminated timber beams when exposed to fire. The influence on the time variation of charring rates based on the evolution of temperature profiles is examined for different fire scenarios and durations as well as different beam's cross-section sizes. Predictions of charring depths provided by numerical simulations of heat transfer and simplified charring rate models are compared. In the absence of a mass transport representation, a Bayesian inference is introduced to identify the temperature-dependent material parameters for the conventional heat transfer model. A similar approach is adopted when adjusting the selected parameters of the charring rate models to account for variations in actual fire scenarios, which potentially depart from standard fire exposure. When compared to experimental results, both approaches confirmed their predictive capabilities, particularly in the stage of initial design. Since presented in the framework of Bayesian statistics, they open the door to fully stochastic analysis with an emphasis on the load bearing capacity of the studied beams. [ABSTRACT FROM AUTHOR]

In the Mogao Grottoes in Dunhuang, China, temperature and relative humidity (RH) fluctuations are the main causes of the observed deterioration. In this paper, we experimentally and numerically analyze hygrothermal transfer in the cave wall of the Mogao Grottoes. A coupled heat and moisture transfer 1D model is developed to simulate the hygrothermal behavior of the cave wall of the Mogao Grottoes, which adopts the temperature and water vapor pressure as driving potentials. The model is implemented in a programming. By constructing the numerical model of the wall under boundary conditions and comparing the measured data and simulation results, we validate the numerical model and analyze the hygrothermal transfer characteristics of the wall. The temperature and moisture profiles of the cave wall are experimentally measured and numerically determined. The simulation results are compared to experimental temperature and RH values, with good agreement despite the simplifying hypotheses adopted during modeling. By analyzing the heat and moisture distributions, we find that the heat and moisture transfer process in the cave wall changes in space and time. The complicated heat and moisture transfer directions vary cyclically. Additionally, moisture transfer in the cave wall reaches the steady state more rapidly than heat transfer. Hygrothermal cycling plays an essential role in the development of mural deterioration. The developed model provides theoretical support and a scientific method for the conservation of cave sites and a quantitative analysis approach to study mural relics. • Apply multidisciplinary method to studying mural disease in historical heritage. • Set up a hygrothermal transfer model for the cave walls, and evaluate the results. • Analyze the heat and moisture transfer properties in cave walls experimentally and numerically. • Provide a salt damage mechanism on murals relating to heat and moisture. [ABSTRACT FROM AUTHOR]