Heating Zone Research Articles

Interfacial Flows and Interfacial Shape Modulation Controlled by the Thermal Action of Light Energy

The review covers the research on thermocapillary convection caused by the thermal action of laser radiation in single-layer and bilayer liquid systems of capillary thickness. The advantages of using optical radiation are the instantaneous delivery of thermal energy to a place on demand (a bulk phase, interfaces); low radiation power required; concentrating heat flux on a spot of a few micrometers; the production of arbitrary spatial distributions of radiation intensity; and, as a result, corresponding thermal fields at a liquid interface and their fast reconfiguration. Thermocapillary stresses at the liquid interfaces lead to the transfer of the liquid and a change in the shape of the interface, in accordance with the distribution of the light-induced thermal field. Studies concerned with the methods of non-destructive testing of liquid media and solids, which are based on a photothermocapillary signal emitted by a laser-induced concave deformation of a thin layer, are considered. Features of thermocapillary deformation of a liquid–air interface caused by local heating of thin and thick (exceeding the capillary length) layers are demonstrated. A part of the review addresses the results of the study of thermocapillary rupture of films in the heating zone and the application of this effect in semiconductor electronics and high-resolution lithography. The works on the light-induced thermocapillary effect in bilayer (multilayer) liquid systems are analyzed, including early works on image recording liquid layer systems, liquid IR transducers, and nonlinear optical media.

A Review on Hot Stamping of Advanced High-Strength Steels: Technological-Metallurgical Aspects and Numerical Simulation

The production of ultra-high strength automotive components requires a multi-directional approach. Hot stamping combines both forming and heat treatment processes to obtain a usually martensitic structure of complicated shaped automotive parts. The preparation for production using hot stamping must involve the latest methods of numerical analysis of both temperature changes and forming, which are applied for an increasing range of materials used. In this paper, the current state of knowledge about the basics of hot stamping, used technological lines, and the current state of material used with applied heat treatments and possible coatings have been reviewed. Moreover, the numerical modeling process has been described. The most important aspects of process automation, including the use of digital twins for simulation and optimization of operational kinetics of the robots accomplishing the production process, analysis and minimization of time of production cycles, and searching for weak operational points of the control systems and for real time visualization of operation of complete line, are considered. The digital twins and corresponding numerical models enable the symmetrical design of real production lines. The details of heat treatment profiles with so called tailored zone heat treatment are provided. Hot stamping is a dynamically developing technology as evidenced by the increasing range of materials used, also from the 3rd generation of advanced high strength (AHSS) steels. It starts to combine forming of symmetric or asymmetric elements with more complex heat treatment processes as required for dual phase (DP) stainless steels or the newest generation of high-strength and ductile medium-manganese steels.

Simulation Study of an Inductively Coupled Plasma Discharge in the Radome Conformal Cavity

In this article, we investigate the influence of external discharge conditions on plasma parameters in the plasma discharge chamber of the radome configuration. We designed a conformal cavity and then used the multiphysics simulation software COMSOL to establish a 2-D axisymmetric model for discharge simulation research. In the study, we found that the changes in coil power and pressure have a noticeable effect on the distribution of plasma parameters. First, the maximum electron density, electric potential, and electron temperature are obtained by changing the power of the coil in a certain pressure argon environment. Then, under the condition of constant coil power, the discharge characteristics of plasma are studied by changing the gas pressure in the cavity. The results show that the change of coil power has a significant impact on the parameter distribution of plasma discharge. The greater the coil power, the greater the electron density, and the more concentrated the distribution. At the same time, the potential induced in the heating zone and the corresponding electron temperature decreased after the reaction stabilized. The increase of gas pressure significantly increases the peak value of electron density and changes the parameter distribution of discharge. However, when the argon pressure exceeds a certain threshold, it will no longer have a significant effect on the distribution of discharge parameters. The general conclusion is that the increase of power and argon pressure plays an essential role in improving the electron density distribution. This conclusion has guiding significance for exploring the law of plasma parameter distribution on electromagnetic scattering characteristics.

Research on the characteristics of micro-pressure waves in high-temperature geothermal railway tunnels and a self-satisfying mitigation method

In this study, through experiments and numerical simulations, micro-pressure waves (MPWs) resulting from the movement of high-speed trains through high-temperature geothermal tunnels were studied, and a self-satisfying MPW mitigation method was proposed. First, a model experiment of a moving high-speed train under local high-temperature conditions was carried out. Then, a relationship between the MPW and length of the heating zone (LH) and the length of the train streamline (12.5 m) was established via numerical simulation. For LH < 12.5 m, the MPW amplitude gradually decreases with increasing LH. For LH > 12.5 m, the MPW amplitude remains basically unchanged. The influence of the circumferential distribution of the heating zone along the tunnel wall on the MPWs was further studied. The research results inspired an MPW mitigation method for tunnels, considering a heating length of 12.5 m and an angle of 225°. Moreover, in a tunnel, electric energy could be generated under slipstream action through a wind turbine installed to provide heating equipment with power, thereby achieving self-satisfaction. This research proposed a new MPW mitigation method for research on MPW mitigation. Moreover, new mitigation methods could facilitate the construction of an environmentally friendly society and provide a new approach to the sustainable development of cities.

Enhancement of Machine Efficiency with Reduced Foil Consumption Prescribed to Printing Industry

Foil stamping is one of the special printing techniques which plays an important role in the packaging design and attention of the customer. We discussed about the different types of foils available in the market and the different layers in the foils. Different concepts and terminology used in hot foiling process and factors like temperature, pressure, thickness of the foil, equipment and tools, and their contribution towards the machine efficiency. How the speed of the machine determines the consumption of foil. We also discussed the concept of single pass run and double pass run, reducing the consumption of electricity by using the relay timer for the heating zones of the machine. Studying and analyzing the consumption and reduction in it through the samples taken from different jobs. Analyzing how MUDAs TIMWOOD can help in increasing efficiency in the industry and how all the factors contribute towards the OEE of the machine.

Fabrication of an Oscillating Thermocycler to Analyze the Canine Distemper Virus by Utilizing Reverse Transcription Polymerase Chain Reaction.

The reverse transcription-polymerase chain reaction (RT-PCR) has been utilized as an effective tool to diagnose the infectious diseases of viruses. In the present work, the oscillating thermocycler is fabricated and performed to carry out the one-step RT-PCR process successfully. The ribonucleic acid (RNA) mixture is pipetted into the fixed sample volume inside an aluminum reaction block. The sample oscillates the pathway onto the linear motion control system and through the specific RT-PCR heating zones with individual homemade thermal control modules. The present oscillating thermocycler combines the merits of the chamber type and the CF type systems. Before PCR, the reaction chamber moves to the low-temperature zone to complete the RT stage and synthesize the complementary deoxyribonucleic acid (DNA). Next, the low-temperature zone is regulated to the annealing zone. Furthermore, the reactive sample is moved back and forth among three isothermal zones to complete PCR. No extra heating zone is required for the RT stage. The total length of the moving displacement of the chamber is within 100 mm. The miniaturization of the oscillating thermocycler can be expected. In our oscillatory device, the denaturation zone located between the annealing and extension zones is suggested as the appropriate arrangement of the heating blocks. Heat management without thermal cross-talk is easy. Finally, an improved oscillating device is demonstrated to execute the RT-PCR process directly, utilized to amplify the canine distemper virus templates successfully, which could be well applied to a low-cost DNA analysis system in the future.

Dynamic response of polycrystalline high energetic systems: Constitutive modeling and application to impact

This paper presents a new polycrystalline model and Lagrangian computational framework for describing the large-scale thermo-mechanical response of energetic materials under dynamic loadings. In our multi-scale computational polycrystalline framework, at the grain level, the elastic response is modeled using an anisotropic Hooke's law, while the plastic behavior is described with a recently developed quadratic anisotropic single-crystal model that accounts for the intrinsic symmetries associated with the lattice of the constituent crystals. The orientation, plastic strains, and stresses in the individual grains are continuously updated, so the predicted macroscopic scale response takes into account the evolution of the thermo-mechanical state at the meso-scale. First, we illustrate the polycrystalline model capabilities by simulating the response of a pentaerythritol tetranitrate (PETN) polycrystalline high energetic system when subjected to dynamic compression. It is shown that there are strong differences in temperature and stresses between the constituent grains, depending on their relative orientation with respect to the wave direction. Moreover, it is shown that the rise in temperature in certain grains may be well in excess of the macroscopic value. We also present 3D finite element simulations of the impact of a penetrator made of a high-strength steel containing the same polycrystalline PETN system. Insights into the complex interactions between the energetic system and the metallic casing material are provided. Furthermore, it is shown that if the crystallinity is neglected, the predicted temperature rise and the extent of the zone of maximum heating in the energetic system during the impact event differ noticeably from those obtained with our polycrystalline model, which accounts for the crystallinity of the PETN material and the anisotropy in the plastic flow of its constituent crystals.

Experimental investigation of laser scan strategy on the microstructure and properties of Inconel 718 parts fabricated by laser powder bed fusion

Inconel 718 (IN718) is a nickel-based superalloy which exhibits excellent tensile and impact resistant properties along with good corrosion resistance at high temperatures. However, due to the high toughness and work hardening, the machinability of this superalloy is low. Therefore, the selective laser melting (SLM) process has been adopted as an efficient technique to fabricate IN718 parts as it overcomes the problems associated with conventional manufacturing of superalloys. In the SLM process, various process parameters like scan strategy, laser power, scan speed, and energy density are defined for the fabrication to regulate the microstructure and thus control the mechanical properties like tensile strength, yield strength, impact strength, and hardness. In the SLM process, the thermal cycles induce residual stress into the part. These residual stresses can be detrimental to the microstructure and hence mechanical properties of the part. Residual stresses lead to warping of the part during the fabrication process, thereby leading to failure of the component. Although each process parameter has an independent and definitive effect on the overall mechanical and metallurgical properties, scan strategy is an independent process parameter which directly affects the level of residual stresses, microstructure, and mechanical properties of the SLM part, as the heat zones in part can be shifted from one location to another by varying the scan strategy. This variation in the area of the heat-affected zone determines the grain size ranging from equiaxed to elongated. Hence, the scan strategy is the only parameter that is varied for this study. The various scan strategies adopted here are chess, striped, flow-optimized, and customized scan strategies. In this study, the microstructural evaluation was deduced, followed by compositional analysis and hardness tests on the SLM fabricated parts. The residual stress of the parts was then determined using the hardness method. This effort was undertaken to identify the effect of scan strategy on residual stress and to discuss the metallurgical interactions between the mechanical and microstructural properties within the IN718 superalloy.

Формирование коаксиальных полей остаточных напряжений в полотне круглой пилы

The working tool of machines with circular cutting units is a circular saw, the condition of which largely determines the quality of material processing. Circular saw blades in the process of operation are subjected to a complex effect of force and temperature factors that cause elongation and deformation of the saw blade, and the occurrence of internal stresses that take it out of the flat form of elastic balance and reduce the tool’s performance. The ability of saws to resist these factors is determined by the rigidity and stability of the saw blade. It is customary to consider a circular saw blade consisting of three zones: peripheral, middle and central. The middle part has the greatest influence on the stability of the saw blade. Initially, after manufacturing, the saw blade has a flat shape of balance, which can be disturbed by any external impact on the saw during the cutting process. The balance disturbance causes the blade and the cutting edge of the saw to deviate from the initial operating condition and reduce the accuracy and quality of wood processing. In order to prevent the influence of external forces, coaxial zones of plastic deformation of a certain width are formed in the middle part of the blade. In this case, under the influence of the created stresses, the effect of web tension appears. In world practice, two methods of forming such zones are used: forging and rolling. The creation of normalized stresses in the circular saw blade is carried out by local mechanical contact action of the working body of the saw tool on the steel saw blade in certain places of the middle zone. Compressive stresses compensating the forces of centrifugal acceleration, the thermal heating of individual zones of the saw blade, the external longitudinal and transverse bending forces that occur in the blade during wood processing are formed in the treated annular zones. The considered methods for creating annular zones of plastic deformation fields involving mechanical action on the saw blade have significant drawbacks, the elimination of which requires fundamentally new technical solutions. It is proposed to form coaxial fields of residual stresses of the saw blade by thermoplastic action consisting in creation of normalized residual stresses in the saw blade by concentrated thermal action on local annular zones coaxially located along the saw blade for the entire thickness of the saw. The formation of coaxial circular fields of residual stresses in the circular saw blade is simulated. The considered method of saw preparation will increase its stability in the process of operation.

Flexible atomic layer deposition system for coating porous materials

Herein, we describe an atomic layer deposition (ALD) system that is optimized for the growth of thin films on high-surface-area, porous materials. The system incorporates a moveable dual-zone furnace allowing for rapid transfer of a powder substrate between heating zones whose temperatures are optimized for precursor adsorption and oxidative removal of the precursor ligands. The reactor can both be evacuated, eliminating the need for a carrier gas during precursor exposure, and rotated, to enhance contact between a powder support and the gas phase, both of which help us to minimize mass transfer limitations in the pores during film growth. The capabilities of the ALD system were demonstrated by growing La2O3, Fe2O3, and LaFeO3 films on a 120 m2 g−1 MgAl2O4 powder. Analysis of these films using scanning transmission electron microscopy and temperature-programmed desorption of 2-propanol confirmed the conformal nature of the oxide films.

Numerical Simulation and Experimental Study of Natural Convection Flow in a Test Bench for Solar Air Heaters

This paper is intended to check the thermal convection flow during a new solar air heater (SAH) test bench, which is conducted in the LASEM laboratory. In fact, the applied system includes two-passage heater solar air separated by an absorber. On the other hand, a glass piece is connected to the box prototype via a pipe. Then, the piece of the glass is attached to the front side of this device in which an absorber is inserted. Moreover, two circular holes are made on the same face of the box prototype. The first is an entry hole through which hot air goes inside, and an exit hole through which air is released into the surrounding area. The study was conducted using the Navier-Stokes equations associated with the k–ω turbulence model through the use of the newly released Ansys 17.0 software to characterize the aero-thermal structure of our new system operating in natural convection. In these conditions, it has been observed that the hot zone created on the mirror side receiving the solar radiation generates an ascendant movement. It goes from the bottom to the top and enters the box prototype. The same phenomenon is also created in the box where the airflow coming from the solar heat escapes into the environment. This movement created between the hot zone of the solar heat and the box prototype is also imposed in the cold zone of the solar heat on the heat-insulating side. In these conditions, the air movement is however from the top to the bottom. Indeed, the acceleration of the air velocity at the inlet of the solar heat is due to the change of the section which is more reduced by comparison to the rest of the air circulation duct. Based on our experimental results generated in a two-passage solar air heater connected to the box prototype, the computational approach and the simulation results were validated. By referring to the classic solar air heater with one passage, the energy efficiency measured in the same conditions was enhanced and presented the efficient one with an improvement of about 27%. Finally, the numerical results are compared to our experimental results and those obtained by the authors. The comparison proved a good agreement.

Substantial transition to clean household energy mix in rural China.

The household energy mix has significant impacts on human health and climate, as it contributes greatly to many health- and climate-relevant air pollutants. Compared to the well-established urban energy statistical system, the rural household energy statistical system is incomplete and is often associated with high biases. Via a nationwide investigation, this study revealed high contributions to energy supply from coal and biomass fuels in the rural household energy sector, while electricity comprised ∼20%. Stacking (the use of multiple sources of energy) is significant, and the average number of energy types was 2.8 per household. Compared to 2012, the consumption of biomass and coals in 2017 decreased by 45% and 12%, respectively, while the gas consumption amount increased by 204%. Increased gas and decreased coal consumptions were mainly in cooking, while decreased biomass was in both cooking (41%) and heating (59%). The time-sharing fraction of electricity and gases (E&G) for daily cooking grew, reaching 69% in 2017, but for space heating, traditional solid fuels were still dominant, with the national average shared fraction of E&G being only 20%. The non-uniform spatial distribution and the non-linear increase in the fraction of E&G indicated challenges to achieving universal access to modern cooking energy by 2030, particularly in less-developed rural and mountainous areas. In some non-typical heating zones, the increased share of E&G for heating was significant and largely driven by income growth, but in typical heating zones, the time-sharing fraction was <5% and was not significantly increased, except in areas with policy intervention. The intervention policy not only led to dramatic increases in the clean energy fraction for heating but also accelerated the clean cooking transition. Higher income, higher education, younger age, less energy/stove stacking and smaller family size positively impacted the clean energy transition.

Numerical analysis of the radiant heating effectiveness of a continuous glass annealing furnace

• A modeling approach for industrial-scale continuous radiative heating furnaces was developed. • The spacing between the glass bottle rows affects the radiative heating effectiveness of the furnace. • Optimum row spacing was found to be 35 % of the bottle diameter. • Operating the furnace at the optimum row spacing, furnace length could be reduced by 8.5%. Radiative heat transfer is the dominant mode of heat transfer in glass annealing furnaces. Especially in electrically heated furnaces due to the nonparticipating nature of the furnace atmosphere the radiative heat transfer predominantly occurs between surfaces. In this regard, in container glass manufacturing the layout of the container glasses inside the furnace can considerably affect the radiative heating effectiveness of the furnace. In this numerical study, the effect of the spacing between the bottle rows on the radiant heating effectiveness of the furnace was numerically investigated. An industrial scale continuous annealing furnace model was used and the combined conduction – radiation heat transfer modes in the furnace were solved with the in-house developed transient solver. The convective heat transfer inside the furnace was not taken into account due to its relatively lower contribution in heat transfer. The computational cost of the numerical model is reduced with the use of a computational domain consisting of 7 bottle rows instead of full 29 bottle rows. Reverse Monte Carlo Ray Tracing method is used to solve for the surface-to-surface radiative heat transfer inside the radiant heating zone and integrated into GPU to reduce its computational cost. Further computational speed-up was achieved with the use of a 2nd order accurate radiation boundary condition implementation. It allows a time step increase of 2.5x in comparison with the first order accurate implementation for the same level of accuracy. Finally, a parametric study on the effect of the spacing between the bottle rows on the radiative heating of the bottles have been conducted. In this regard, the spacing between the bottle rows and the conveyor speed have been altered in a way that the throughput of the furnace, the number bottles processed per unit time, is kept constant. The study shows that there is an optimum spacing value between the bottle rows. For the particular bottle geometry considered in this study, the optimum row spacing value is found to be 35% of the bottle diameter. Running the furnace at this optimum value, the length of the heating zone could be reduced by 8.5% compared to the case when the furnace was operated with the bottles almost in touch with each other.

Nonequilibrium Factor in the Structure of a Curved Shock Wave Refracted Into an Intensively Heated Medium

The role of thermal nonequilibrium state in the structure of a curved shock wave during its refraction into an intensively heated medium has been studied analytically and numerically. At elevated gas temperatures common for optical discharges and for moderate-to-strong shock intensities, the width of the zone of variable specific heat is on sub- to mm scale, and thus is comparable to the geometrical scale of the problem. The asymptotic temperature gap, the specific temperature distribution in the zone, and the relaxation zone width are discussed in connection with the changes in the contrast level of the shock images obtained with shadow techniques. Numerical examples are presented in spherical and elliptical geometries for the conditions of a laser-induced breakdown in pure nondissociating nitrogen gas.

Developmental programming: prenatal and postnatal consequences of hyperthermia in dairy cows and calves

With global warming, the incidence of heat stress in dairy cows is increasing in many countries. Temperatures outside the thermoneutral zone (heat stress) are one of the environmental factors with the greatest impact on milk production and reproductive performance of dairy cows. In addition to several biological mechanisms that may contribute to the effects of fetal programming, epigenetic modifications have also been investigated as possible mediators of the observed associations between maternal heat stress during late gestation and performance and health later in life. In utero programming of these offspring may coordinate changes in thermoregulation, mammary gland development, and milk production ability at different developmental stages. This review examines the effects of prenatal and postnatal hyperthermia on the developmental outcomes of dairy cows, as well as the physiological and molecular mechanisms that may be responsible for the negative phenotypic consequences of heat stress that persist throughout the neonatal and adult periods and may have multigenerational implications. The physiological and molecular mechanisms underlying the negative phenotypic consequences of heat stress are discussed. Research challenges in this area, future research recommendations, and therapeutic applications are also discussed. In summary, strategies to reduce heat stress during the dry period should consider not only the productivity of the pregnant cow but also the well-being of the newborn calf.

Spatial matching relationship of dual heat sources in electromagnetic heating of pipes

• Dual heat sources reduce the probability of latent defects in electromagnetic heating. • The mechanism of the interference of dual heat sources on the induced magnetic field. • Reveal the spatial matching relationship of dual heat sources under moving conditions. In medium-frequency heat treatment, it is difficult to thoroughly heat the interior of welds of heavy-wall pipes, and blind zones of heating or overheating zones with latent defects are very readily present. To solve the electromagnetic-heating-induced latent defects, we researched the mode of heat transfer inside the welds with heat sources under motion conditions to determine the temperature field evolution, spatial magnetic field distribution, and spatial matching relationship in cases of dual heat sources interfering with each other, tangential to each other, and not interfering with each other. With the increase in the axial spacing between the internal and external heat sources, the magnetic field intensity at the middle of the thickest part of the welding seam on the steel pipe increased and then decreased. When the heat sources interfered with each other, the temperature rise at the weld center from electromagnetic heating was no longer fast after the Curie point was reached. The induced magnetic field heating concentration positions shifted toward both sides of the weld center. The latent defect area was reduced by 18.7 mm 2 when the spacing between the internal and external heat sources was 19 mm. This study explores the dual-heat-source interaction mechanism for the first time in the heat treatment of pipes to minimize the blind zones of heating and overheating zones.

Dynamic simulation of hydrogen-based zero energy buildings with hydrogen energy storage for various climate conditions

Solar energy systems are an effective way to meet the needs of zone heating, cooling, electricity, and domestic hot water. However, to reach sustainability, and energy storage unit should be considered for installation. In this study, two combined cooling, heating and power (CCHP) systems are simulated and studied using TRNSYS software; both using natural gas engine generators and photovoltaics as prime movers and a hydrogen fuel cell/electrolyzer storage unit, one with absorption chiller and another with compression chiller cooling. For the study, a residential building is modeled for three major populated climate zones of the United States of America, namely, Hot-humid, mixed-humid and cold using DesignBuilder and EnergyPlus software. The energy demand for its HVAC operation and domestic electricity is obtained and used for system simulation in TRNSYS software. Due to choosing actual equipment for the CCHP arrangement, precise economic and environmental models are designed to further evaluate the possibility of execution of the system. The results show that absorption chiller-equipped CCHP has better performance both environmentally and economically. In addition, the outcome shows that the suggested systems show less favorability to be utilized in hot humid climate zones.

Research on the influence of different heating zone lengths on pressure waves and a newly designed method of pressure wave mitigation in railway tunnels

In this paper, through experimental and numerical simulation methods, the influence of the tunnel heating zone length on the pressure wave peak and temperature field changes is investigated in tunnels with different heating zone lengths. The accuracy of the applied simulation algorithm is verified against experimental data from moving model tests. Via numerical simulations, the changes in the pressure wave peak value and temperature field are explored with five heating zone lengths. For the compression wave, this research revealed that when LH (length of the heating zone) < LT (length of the train) and that with an increase in LH, the peak value of the initial compression wave notably decreases. When LH > LT, the compression wave peak value remains basically stable. In regard to the expansion wave at tunnel measurement points, for L (from tunnel entrance) ⩽ 110 m, the initial expansion wave peak exhibits small fluctuations. At L > 110 m, with an increase in the heating zone length, the peak value of the expansion wave peak gradually decreases. In addition, the dynamic temperature field changes. The obtained research results provide a new idea to reduce the peak pressure value in a tunnel. In addition, this study provides a method for pressure wave mitigation during tunnel design and guidance for passenger comfort improvement in future city railway tunnels.

A Simplified Numerical Approach to Characterize the Thermal Response of a Moving Bed Solar Reactor

Abstract Concentrated solar thermochemical storage in the form of a zero-emission fuel is a promising option to produce long-duration energy storage. Solar fuel is produced using a cavity reactor that captures concentrated solar radiation from a solar field of heliostats. In this paper, heat transfer model of a tubular plug-flow reactor designed and manufactured for a solar fuel production is presented. Experimental data collected from a fixed bed tubular reactor testing are used for model comparison. The system consists of an externally heated tube with counter-current flowing gas and moving solid particles as the heated media. The proposed model simulates the dynamic behavior of temperature profiles of the tube wall, gas, and particles under various gas flowrates and residence times. The heat transfer between gas–wall, solid particle–wall, and gas–solid particle is numerically studied. The model results are compared with the results of experiments done using a 4 kW furnace with a 150 mm heating zone surrounding a horizontal alumina tube (reactor) with 50.8 mm outer diameter and thickness of 3.175 mm. Solid fixed particles of magnesium manganese oxide (MgMn2O4) with the size of 1 mm are packed within the length of 250 mm at the center of the tube length. Simulation results are assessed with respect to fixed bed experimental data for four different gas flowrates, namely, 5, 10, 15, and 20 standard liters per minute of air, and furnace temperatures in the range of 200–1200 °C. The simulation results showed good agreement with maximum steady state error that is less than 6% of those obtained from the experiments for all runs. The proposed model can be implemented as a low-order physical model for the control of temperature inside plug-flow reactors for thermochemical energy storage applications.

Simulation of Concrete in Winter with Self-Limiting Heating Band

In order to investigate the temperature distribution and cracking risk of concrete in winter under the combined action of heating zone and air layer, the analytical calculation method of early age concrete temperature field of concrete component under the combined action of self-limiting temperature band, cement hydration and air layer was established by taking concrete prism with self-limiting temperature band as an example. The model is applied to calculate and analyze the temperature distribution of concrete under different boundary conditions and different additional thermal field modes. The results show that: Under the conditions of internal layout, surface layout and thermal insulation layer outside the formwork, all components reach the critical strength after heating and curing for three days, which indicates that the heating band can provide temperature conditions for concrete curing in winter. Comparing the temperature field of different layout positions of heating belt, the uniformity of temperature field of heating belt outside the formwork is better than the other two layout methods.