During the propagation of high-power lasers within internal channels,the laser beam heats the propagation medium,causing the thermal blooming effect that degrades the beam quality at the output.The intricate configura...During the propagation of high-power lasers within internal channels,the laser beam heats the propagation medium,causing the thermal blooming effect that degrades the beam quality at the output.The intricate configuration of the optical path within the internal channel necessitates complex and time-consuming efforts to assess the impact of thermal blooming effect on the optical path.To meet the engineering need for rapid evaluation of thermal blooming effect in optical paths,this study proposed a rapid simulation method for the thermal blooming effect in internal optical paths based on the finite element method.This method discretized the fluid region into infinitesimal elements and employed finite element method for flow field analysis.A simplified analytical model of the flow field region in complex internal channels was established,and regions with similar thermal blooming effect were divided within this model.Based on the calculated optical path differences within these regions,numerical simulations of phase distortion caused by thermal blooming were conducted.The calculated result were compared with those obtained using the existing methods.The findings reveal that for complex optical paths,the discrepancy between the two approaches is less than 3.6%,with similar phase distortion patterns observed.For L-type units,this method and the existing methods identify the same primary factors influencing aberrations and exhibit consistent trends in their variation.This method was used to analyze the impact of thermal blooming effect in a straight channel under different gravity directions.The results show that phase distortion varies with changes in the direction of gravity,and the magnitude of the phase difference is strongly correlated with the component of gravity perpendicular to the optical axis.Compared to the existing methods,this approach offers greater flexibility,obviates the need for complex custom analysis programming.The analytical results of this method enable a rapid assessment of the thermal blooming effect in optical paths within the internal channel.This is especially useful during the engineering design.These results also provide crucial references for developing strategies to suppress thermal blooming effect.展开更多
This study focuses on the thermal management of 4680-type cylindrical lithium-ion battery packs utilizing NCM811 chemistry.It establishes coupled multi-physics models for both immersion and serpentine cold plate cooli...This study focuses on the thermal management of 4680-type cylindrical lithium-ion battery packs utilizing NCM811 chemistry.It establishes coupled multi-physics models for both immersion and serpentine cold plate cooling systems.Through a combination of numerical simulation and experimental validation,the technical advantages and mechanisms of immersion cooling are systematically explored.Simulation results indicate that under a 3C fast-charging condition(inlet temperature 20℃,flow rate 36 L/min),the immersion cooling structure 3demonstrates a triple enhancement in thermal performance compared to the cold plate structure 1:a 13.06%reduction in peak temperature,a 31.67%decrease in overall maximum temperature difference,and a 47.62%decrease in single-cell temperature deviation,while also reducing flow resistance by 33.61%.Furthermore,based on the immersion cooling model,a small battery module comprising seven cylindrical cells was designed for thermal runaway testing via nail penetration.The results show that the peak temperature of the triggered cell was limited to 437.6℃,with a controllable temperature rise gradient of only 3.35℃/s and a rapid cooling rate of 0.6℃/s.The maximum temperature rise of adjacent cells was just 64.8℃,effectively inhibiting thermal propagation.Post-test disassembly revealed that the non-triggered cells retained>99.2%of their original voltage and>99%structural integrity,confirming the module’s ability to achieve“localized failure with global stability.”展开更多
In this study,we simulated the thermal behavior of the mud-brick walls of a Nubian vault.We used EnergyPlus software for the simulation.The results obtained showed that the indoor temperature varies from 25.5℃ to 26....In this study,we simulated the thermal behavior of the mud-brick walls of a Nubian vault.We used EnergyPlus software for the simulation.The results obtained showed that the indoor temperature varies from 25.5℃ to 26.5℃ for the period of January 2018.It varies from 33.2℃ to 33.6℃ with an average value of 33.1℃ for the month of April 2018.For the period of July 2018,it varies from 30.3℃ to 32.2℃ with an average value of 31.2℃..Relative humidity for the period of July ranged from 62.3%to 73.5%,with an average value of 67.9%.The simulation enabled us to compare simulated and measured temperature and humidity values.We found that the level of thermal comfort in the Nubian vault is acceptable in both cool and hot periods.In view of these results,we can say that the Nubian vault is an architecture suited to our climate.The technical concept of the Nubian vault is adapted to the climatic conditions and traditional know-how of the Sahel.We also found that the use of raw earth,a locally available material,and the Nubian vault architectural process,contribute to thermal comfort and a reappropriation of local and adapted know-how.展开更多
As a product of the deep integration between next-generation information technology and industrial systems,digital twin technology has demonstrated significant advantages in real-time monitoring,predictive maintenance...As a product of the deep integration between next-generation information technology and industrial systems,digital twin technology has demonstrated significant advantages in real-time monitoring,predictive maintenance,and optimization decision-making for thermal power plants.To address challenges such as low equipment efficiency,high maintenance costs,and difficulties in safety risk management in traditional thermal power plants,this study developed a digital twin simulation system that covers the entire lifecycle of power generation units.The system achieves real-time collection and processing of critical parameters such as temperature,pressure,and flow rate through a collaborative architecture integrating multi-source heterogeneous sensor networks with Programmable Logic Controllers(PLCs).A three-tier processing framework handles data preprocessing,feature extraction,and intelligent analysis,while establishing a hybrid storage system combining time-series databases and relational databases to enable millisecond-level queries and data traceability.The simulation model development module employs modular design methodology,integrating multi-physics coupling algorithms including computational fluid dynamics(CFD)and thermal circulation equations.Automated parameter calibration is achieved through intelligent optimization algorithms,with model accuracy validated via unitlevel verification,system-level cascaded debugging tests,and virtual test platform simulations.Based on the modular layout strategy,the user interface and interaction module integrates 3D plant panoramic view,dynamic equipment model and multi-mode interaction channel,supports cross-terminal adaptation of PC,mobile terminal and control screen,and improves fault handling efficiency through AR assisted diagnosis function.展开更多
The hybrid CO_(2) thermal technique has achieved considerable success globally in extracting residual heavy oil from reserves following a long-term steam stimulation process.Using microscopic visualization experiments...The hybrid CO_(2) thermal technique has achieved considerable success globally in extracting residual heavy oil from reserves following a long-term steam stimulation process.Using microscopic visualization experiments and molecular dynamics(MD)simulations,this study investigates the microscopic enhanced oil recovery(EOR)mechanisms underlying residual oil removal using hybrid CO_(2) thermal systems.Based on the experimental models for the occurrence of heavy oil,this study evaluates the performance of hybrid CO_(2) thermal systems under various conditions using MD simulations.The results demonstrate that introducing CO_(2) molecules into heavy oil can effectively penetrate and decompose dense aggregates that are originally formed on hydrophobic surfaces.A stable miscible hybrid CO_(2) thermal system,with a high effective distribution ratio of CO_(2),proficiently reduces the interaction energies between heavy oil and rock surfaces,as well as within heavy oil.A visualization analysis of the interactions reveals that strong van der Waals(vdW)attractions occur between CO_(2) and heavy oil molecules,effectively promoting the decomposition and swelling of heavy oil.This unlocks the residual oil on the hydrophobic surfaces.Considering the impacts of temperature and CO_(2) concentration,an optimal gas-to-steam injection ratio(here,the CO_(2):steam ratio)ranging between 1:6 and 1:9 is recommended.This study examines the microscopic mechanisms underlying the hybrid CO_(2) thermal technique at a molecular scale,providing a significant theoretical guide for its expanded application in EOR.展开更多
Molecular dynamics （MD） simulations of monocrystalline copper （100） surface during nanomachining process were performed based on a new 3D simulation model. The material removal mechanism and system temperature dis...Molecular dynamics （MD） simulations of monocrystalline copper （100） surface during nanomachining process were performed based on a new 3D simulation model. The material removal mechanism and system temperature distribution were discussed. The simulation results indicate that the system temperature distribution presents a roughly concentric shape, a steep temperature gradient is observed in diamond cutting tool, and the highest temperature is located in chip. Centrosymmetry parameter method was used to monitor defect structures. Dislocations and vacancies are the two principal types of defect structures. Residual defect structures impose a major change on the workpiece physical properties and machined surface quality. The defect structures in workpiece are temperature dependent. As the temperature increases, the dislocations are mainly mediated from the workpiece surface, while the others are dissociated into point defects. The relatively high cutting speed used in nanomachining results in less defect structures, beneficial to obtain highly machined surface quality.展开更多
In order to study the indoor thermal environments in university classrooms in Tianjin,a field study and a questionnaire survey for a main teaching building are carried out.First,the thermal sensations of participants ...In order to study the indoor thermal environments in university classrooms in Tianjin,a field study and a questionnaire survey for a main teaching building are carried out.First,the thermal sensations of participants in the typical classrooms are studied by 180 questionnaires.Then,based on the measured data,the temperature changes in the classrooms during a year are simulated by the DeST software.The results show that the indoor thermal environments in the northern classrooms on the first floor are better than those in other classrooms.And the measurement results accord with the simulation results.These results can be used as a reference for the study of the indoor thermal environments in other seasons.展开更多
The mesoscopic simulation technique was applied to describe the phase separation behavior ofpolyimide blends and used for design of immiscible polyimide/BN blend films with enhanced thermal conductivity. The simulatio...The mesoscopic simulation technique was applied to describe the phase separation behavior ofpolyimide blends and used for design of immiscible polyimide/BN blend films with enhanced thermal conductivity. The simulation equilibrium morphologies of different poly（amic acid） （PAA） blend systems were investigated and compared with optical images of corresponding polyimide blend films obtained by experiment. The immiscible polyimide blend fihns containing nano-/micro-sized BN with vertical double percolation structure were prepared. The result indicated that the thermal conductivity of polyimide blend film with 25 wt% nano-sized BN reached 1,16 W/（m·K）, which was 236% increment compared with that of the homogenous film containing the same BN ratio. The significant enhancement in thermal conductivity was attributed to the good phase separation of polyimide matrix, which made the inorganic fillers selectively localized in one continuous phase with high packing density, consequently, forming the effective thermal conductive pathway.展开更多
Some of the remarkable characteristics of natural landslides, such as surprisingly long travel distances and high velocities, have been attributed to the mechanisms of frictional heating and thermal pressurization. In...Some of the remarkable characteristics of natural landslides, such as surprisingly long travel distances and high velocities, have been attributed to the mechanisms of frictional heating and thermal pressurization. In this work, this mechanism is combined with a depth-averaged model to simulate the long runout of landslides in the condition of deformation. Some important factors that influence frictional heating and thermal pressurization within the shear zone are further considered, including velocity profile and pressurization coefficient. In order to solve the coupled equations, a combined computational method based on the finite volume method and quadratic upwind interpolation for convective kinematics scheme is proposed. Several numerical tests are performed to demonstrate the feasibility of the computational scheme, the influence of thermal pressurization on landslide run-out, and the potential of the model to simulate an actual landslide.展开更多
hi this paper, the non-linear finite element method had been applied to calculate the thermal stress evolving process of the large-scale bearing roller during heating process of final heat treatment. It was found that...hi this paper, the non-linear finite element method had been applied to calculate the thermal stress evolving process of the large-scale bearing roller during heating process of final heat treatment. It was found that two stress peaks appeared during heating process and the second stress peak was higher than the first. If the preheating time was elongated, the second stress peak was reduced distinctly. Therefore, the pre-heating time should be elongated suitably to ensure safety in the practical manufacture process.展开更多
To decrease thermal stress during laser metal deposition shaping(LMDS)process,it is of great importance to learn the transient thermal stress distribution regularities.Based on the“element life and death”technique o...To decrease thermal stress during laser metal deposition shaping(LMDS)process,it is of great importance to learn the transient thermal stress distribution regularities.Based on the“element life and death”technique of finite element analy- sis(FEA),a three-dimensional multi-track and multi-layer numerical simulation model for LMDS is developed with ANSYS parametric design language(APDL)for the first time,in which long-edge parallel reciprocating scanning paths is introduced. Through the model,detailed simulations of thermal stress during whole metal cladding process are conducted,the generation and distribution regularities of thermal stress are also discussed in detail.Using the same process parameters,the simulation results show good agreement with the features of samples which fabricated by LMDS.展开更多
The influences of superheat and cooling intensity on macrostructure and macrosegregation of one new kind duplex stainless steel(DSS)were studied.Thermal simulation equipment was applied to prepare samples,which could ...The influences of superheat and cooling intensity on macrostructure and macrosegregation of one new kind duplex stainless steel(DSS)were studied.Thermal simulation equipment was applied to prepare samples,which could reproduce the industrial processes of DSS manufactured by a vertical continuous slab caster.Macrostructure and macrosegregation were analyzed using the digital single lens reflex and laser-induced breakdown spectroscope(LIBSOPA-200),respectively.The percentage of both chill zone and center equiaxed zone increases with the superheat decreasing,while that of the columnar zone decreases.There is only equiaxed grain existing as the superheat is 10 and 20℃.The lower the superheat is,the coarser the gain size is.High cooling intensity in mold could remarkably decrease the chill zone length and refine the grains in chill zone and center equiaxed zone.The influences of cooling intensity on macrosegregation are greater than those of superheat.The macrosegregation of Si,Mn and Cr is slightly dependent on superheat,while that of Cu,Mo and Ni changes greatly with superheat increasing.展开更多
A new reliable thermal simulation system for studying solidification of heavy section ductile iron has been developed using computer feedback control and artificial intelligent methods. Results of idle test indicate t...A new reliable thermal simulation system for studying solidification of heavy section ductile iron has been developed using computer feedback control and artificial intelligent methods. Results of idle test indicate that the temperature in the system responses exactly to the inputted control data and the temperature control error is less than ±0.5%. It is convenient to simulate solidification of heavy section ductile iron using this new system. Results of thermal simulation experiments show that the differences in nodularity and number of graphite nodule per unit area in the thermal simulation specimen and the actual heavy section block is less than 5% and 10%, respectively.展开更多
Using an artificial intelligent instrument and a computer feedback control method, a new thermal simulation systemis studied. Based on numerical simulation of casting solidification, a sample in the new system success...Using an artificial intelligent instrument and a computer feedback control method, a new thermal simulation systemis studied. Based on numerical simulation of casting solidification, a sample in the new system successfully simulatedthe solidification of heavy section ductile iron. The results show that the new thermal simulation system is accurateand reliable. Not only cooling curve but also graphite in the center of the thermal sample and the heavy sectionductile iron is identical. Realization of accurate thermal simulation of solidification in heavy section ductile iron willbe helpful for studying formation mechanism and controlling graphite degeneration in heavy section ductile iron.展开更多
Stretched polyethylene(PE)fibers are found to have super high thermal conductivity,while the bulk of polyethylene is usually thermal insulating even for those with high crystalline degree.A molecular dynamic simulatio...Stretched polyethylene(PE)fibers are found to have super high thermal conductivity,while the bulk of polyethylene is usually thermal insulating even for those with high crystalline degree.A molecular dynamic simulation is deliberately carried out to examine the relationship between chain configuration and thermal conductivity of polyethylene.In this simulation study,independent and interacting PE chains being stretched are compared with the aim to find out the effect of stretching on thermal conductivity of PE.Various crystallization conditions for PE bulk are considered.It is found that heat transports predominately along the covalent chain rather than across chains in PE crystals.Our simulation study helps to understand experimental findings on thermal conductivity of PE at different states.W e also predict that amorphous PE may be super thermally conductive if chains are strictly stretched along heat flux.展开更多
The relationship between the t8/5 and micro-hardness, impact toughness in the heat affected zone （HAZ） of ASME SA213-792 at peak temperature of 1 350 ℃ was studied by thermal simulation. The result shows that the m...The relationship between the t8/5 and micro-hardness, impact toughness in the heat affected zone （HAZ） of ASME SA213-792 at peak temperature of 1 350 ℃ was studied by thermal simulation. The result shows that the micro-hardness of HAZ rises at the beginning and then decreases with increasing of t8/5 , whereas the impact toughness presents reverse trend. The distribution of precipitates in substrate has great influence on the impact toughness of HAZ. When the t8/5 is 40 s, chain-like precipitates lower the impact toughness of HAZ seriously.展开更多
K439B nickel-based superalloy is a new type of high-temperature material.There is insufficient research on its constitutive equations and numerical modeling of thermal stress.Isothermal tensile experiments of K439B su...K439B nickel-based superalloy is a new type of high-temperature material.There is insufficient research on its constitutive equations and numerical modeling of thermal stress.Isothermal tensile experiments of K439B superalloy at different temperatures(20°C-1,000°C)and strain rates(1.33×10^(-3)s^(-1)-5.33×10^(-3)s^(-1))were performed by using a Gleeble-3800 simulator.The elastic moduli at different temperatures(20°C-650°C)were measured by resonance method.Subsequently,stress-strain curves were measured for K439B superalloy under different conditions.The elastic-viscoplastic constitutive equations were established and the correspongding parameters were solved by employing the Perzyna model.The verification results indicate that the calculated values of the constitutive equations are in good agreement with the experimental values.On this basis,the influence of process parameters on thermal stress was investigated by numerical simulation and orthogonal experimental design.The results of orthogonal experimental design reveal that the cooling mode of casting has a significant influence on the thermal stress,while pouring temperature and preheating temperature of shell mold have minimal impact.The distribution of physical fields under optimal process parameters,determined based on the orthogonal experimental design results,was simulated.The simulation results determine separately the specific positions with maximum values for effective stress,plastic strain,and displacement within the casting.The maximum stress is about 1,000.0 MPa,the plastic strain is about 0.135,and the displacement is about 1.47 mm.Moreover,the distribution states of thermal stress,strain,and displacement are closely related to the distribution of the temperature gradient and cooling rate in the casting.The research would provide a theoretical reference for exploring the stress-strain behavior and numerical modeling of the effective stress of the alloy during the casting process.展开更多
Internal thermally coupled distillation columns (ITCDIC) are the frontier of distillation energy saving research. In this paper, a novel energy saving model of ideal ITCDIC and a simulation algorithm are presented,upo...Internal thermally coupled distillation columns (ITCDIC) are the frontier of distillation energy saving research. In this paper, a novel energy saving model of ideal ITCDIC and a simulation algorithm are presented,upon which a series of comparative studies on energy savings with conventional distillation columns are carried out. Furthermore, we present an optimization model of ideal ITCDIC, which can be used to achieve the maximum energy saving and find the optimal design parameters directly. The binary system of benzene-toluene is adopted for the illustrative example of simulation and optimization. The results show that the maximum energy saving of ITCDIC is 52.25% (compared with energy consumption of conventional distillation under the minimum reflux ratio operation); the optimal design parameters are obtained, where the rectifying section pressure and the feed thermal condition are Pr=0.3006 MPa and q=0.5107 respectively.展开更多
Based on the chasteal nucleation theory, the kinetic precipitation model of carbon - nitride particles in weld HAZ is proposed. Using the model,welding simulation technology and the quantitative metallo- graphic anal...Based on the chasteal nucleation theory, the kinetic precipitation model of carbon - nitride particles in weld HAZ is proposed. Using the model,welding simulation technology and the quantitative metallo- graphic analysis,the precipitation transformation temperatue (PTT) curve is obtained.The data from the simulated welds are in good apreement with the value that the PTT curves predicated.展开更多
In the casting process,in order to compensate for the solidification shrinkage to obtain higher dimensional accuracy of the casting,it is often necessary to modify the original design of castings,and a suitable compen...In the casting process,in order to compensate for the solidification shrinkage to obtain higher dimensional accuracy of the casting,it is often necessary to modify the original design of castings,and a suitable compensation method has a decisive impact on the dimensional accuracy of the actual casting.In this study,based on solidification simulation,a design method of reverse deformation is proposed,and two compensation methods,empirical compensation and direct reverse deformation,are implemented.The simulation results show that the empirical compensation method has problems such as difficulty in determining the parameters and satisfaction of both the overall and local accuracy at the same time;while based on the simulation results for each node of the casting,the direct reverse deformation design achieves the design with shape.In addition,the casting model can be optimized through iterative revisions,so that higher dimensional accuracy can be continuously obtained in the subsequent design process.Therefore,the direct reverse deformation design is more accurate and reasonable compared to empirical compensation method.展开更多
文摘During the propagation of high-power lasers within internal channels,the laser beam heats the propagation medium,causing the thermal blooming effect that degrades the beam quality at the output.The intricate configuration of the optical path within the internal channel necessitates complex and time-consuming efforts to assess the impact of thermal blooming effect on the optical path.To meet the engineering need for rapid evaluation of thermal blooming effect in optical paths,this study proposed a rapid simulation method for the thermal blooming effect in internal optical paths based on the finite element method.This method discretized the fluid region into infinitesimal elements and employed finite element method for flow field analysis.A simplified analytical model of the flow field region in complex internal channels was established,and regions with similar thermal blooming effect were divided within this model.Based on the calculated optical path differences within these regions,numerical simulations of phase distortion caused by thermal blooming were conducted.The calculated result were compared with those obtained using the existing methods.The findings reveal that for complex optical paths,the discrepancy between the two approaches is less than 3.6%,with similar phase distortion patterns observed.For L-type units,this method and the existing methods identify the same primary factors influencing aberrations and exhibit consistent trends in their variation.This method was used to analyze the impact of thermal blooming effect in a straight channel under different gravity directions.The results show that phase distortion varies with changes in the direction of gravity,and the magnitude of the phase difference is strongly correlated with the component of gravity perpendicular to the optical axis.Compared to the existing methods,this approach offers greater flexibility,obviates the need for complex custom analysis programming.The analytical results of this method enable a rapid assessment of the thermal blooming effect in optical paths within the internal channel.This is especially useful during the engineering design.These results also provide crucial references for developing strategies to suppress thermal blooming effect.
文摘This study focuses on the thermal management of 4680-type cylindrical lithium-ion battery packs utilizing NCM811 chemistry.It establishes coupled multi-physics models for both immersion and serpentine cold plate cooling systems.Through a combination of numerical simulation and experimental validation,the technical advantages and mechanisms of immersion cooling are systematically explored.Simulation results indicate that under a 3C fast-charging condition(inlet temperature 20℃,flow rate 36 L/min),the immersion cooling structure 3demonstrates a triple enhancement in thermal performance compared to the cold plate structure 1:a 13.06%reduction in peak temperature,a 31.67%decrease in overall maximum temperature difference,and a 47.62%decrease in single-cell temperature deviation,while also reducing flow resistance by 33.61%.Furthermore,based on the immersion cooling model,a small battery module comprising seven cylindrical cells was designed for thermal runaway testing via nail penetration.The results show that the peak temperature of the triggered cell was limited to 437.6℃,with a controllable temperature rise gradient of only 3.35℃/s and a rapid cooling rate of 0.6℃/s.The maximum temperature rise of adjacent cells was just 64.8℃,effectively inhibiting thermal propagation.Post-test disassembly revealed that the non-triggered cells retained>99.2%of their original voltage and>99%structural integrity,confirming the module’s ability to achieve“localized failure with global stability.”
文摘In this study,we simulated the thermal behavior of the mud-brick walls of a Nubian vault.We used EnergyPlus software for the simulation.The results obtained showed that the indoor temperature varies from 25.5℃ to 26.5℃ for the period of January 2018.It varies from 33.2℃ to 33.6℃ with an average value of 33.1℃ for the month of April 2018.For the period of July 2018,it varies from 30.3℃ to 32.2℃ with an average value of 31.2℃..Relative humidity for the period of July ranged from 62.3%to 73.5%,with an average value of 67.9%.The simulation enabled us to compare simulated and measured temperature and humidity values.We found that the level of thermal comfort in the Nubian vault is acceptable in both cool and hot periods.In view of these results,we can say that the Nubian vault is an architecture suited to our climate.The technical concept of the Nubian vault is adapted to the climatic conditions and traditional know-how of the Sahel.We also found that the use of raw earth,a locally available material,and the Nubian vault architectural process,contribute to thermal comfort and a reappropriation of local and adapted know-how.
文摘As a product of the deep integration between next-generation information technology and industrial systems,digital twin technology has demonstrated significant advantages in real-time monitoring,predictive maintenance,and optimization decision-making for thermal power plants.To address challenges such as low equipment efficiency,high maintenance costs,and difficulties in safety risk management in traditional thermal power plants,this study developed a digital twin simulation system that covers the entire lifecycle of power generation units.The system achieves real-time collection and processing of critical parameters such as temperature,pressure,and flow rate through a collaborative architecture integrating multi-source heterogeneous sensor networks with Programmable Logic Controllers(PLCs).A three-tier processing framework handles data preprocessing,feature extraction,and intelligent analysis,while establishing a hybrid storage system combining time-series databases and relational databases to enable millisecond-level queries and data traceability.The simulation model development module employs modular design methodology,integrating multi-physics coupling algorithms including computational fluid dynamics(CFD)and thermal circulation equations.Automated parameter calibration is achieved through intelligent optimization algorithms,with model accuracy validated via unitlevel verification,system-level cascaded debugging tests,and virtual test platform simulations.Based on the modular layout strategy,the user interface and interaction module integrates 3D plant panoramic view,dynamic equipment model and multi-mode interaction channel,supports cross-terminal adaptation of PC,mobile terminal and control screen,and improves fault handling efficiency through AR assisted diagnosis function.
基金financially supported by the National Natural Science Foundation of China(No.U20B6003)the China Scholarship Council(No.202306440015)a project of the China Petroleum&Chemical Corporation(No.P22174)。
文摘The hybrid CO_(2) thermal technique has achieved considerable success globally in extracting residual heavy oil from reserves following a long-term steam stimulation process.Using microscopic visualization experiments and molecular dynamics(MD)simulations,this study investigates the microscopic enhanced oil recovery(EOR)mechanisms underlying residual oil removal using hybrid CO_(2) thermal systems.Based on the experimental models for the occurrence of heavy oil,this study evaluates the performance of hybrid CO_(2) thermal systems under various conditions using MD simulations.The results demonstrate that introducing CO_(2) molecules into heavy oil can effectively penetrate and decompose dense aggregates that are originally formed on hydrophobic surfaces.A stable miscible hybrid CO_(2) thermal system,with a high effective distribution ratio of CO_(2),proficiently reduces the interaction energies between heavy oil and rock surfaces,as well as within heavy oil.A visualization analysis of the interactions reveals that strong van der Waals(vdW)attractions occur between CO_(2) and heavy oil molecules,effectively promoting the decomposition and swelling of heavy oil.This unlocks the residual oil on the hydrophobic surfaces.Considering the impacts of temperature and CO_(2) concentration,an optimal gas-to-steam injection ratio(here,the CO_(2):steam ratio)ranging between 1:6 and 1:9 is recommended.This study examines the microscopic mechanisms underlying the hybrid CO_(2) thermal technique at a molecular scale,providing a significant theoretical guide for its expanded application in EOR.
基金Project (50925521) supported by the National Natural Science Fund for Distinguished Young Scholars of China
文摘Molecular dynamics （MD） simulations of monocrystalline copper （100） surface during nanomachining process were performed based on a new 3D simulation model. The material removal mechanism and system temperature distribution were discussed. The simulation results indicate that the system temperature distribution presents a roughly concentric shape, a steep temperature gradient is observed in diamond cutting tool, and the highest temperature is located in chip. Centrosymmetry parameter method was used to monitor defect structures. Dislocations and vacancies are the two principal types of defect structures. Residual defect structures impose a major change on the workpiece physical properties and machined surface quality. The defect structures in workpiece are temperature dependent. As the temperature increases, the dislocations are mainly mediated from the workpiece surface, while the others are dissociated into point defects. The relatively high cutting speed used in nanomachining results in less defect structures, beneficial to obtain highly machined surface quality.
文摘In order to study the indoor thermal environments in university classrooms in Tianjin,a field study and a questionnaire survey for a main teaching building are carried out.First,the thermal sensations of participants in the typical classrooms are studied by 180 questionnaires.Then,based on the measured data,the temperature changes in the classrooms during a year are simulated by the DeST software.The results show that the indoor thermal environments in the northern classrooms on the first floor are better than those in other classrooms.And the measurement results accord with the simulation results.These results can be used as a reference for the study of the indoor thermal environments in other seasons.
文摘The mesoscopic simulation technique was applied to describe the phase separation behavior ofpolyimide blends and used for design of immiscible polyimide/BN blend films with enhanced thermal conductivity. The simulation equilibrium morphologies of different poly（amic acid） （PAA） blend systems were investigated and compared with optical images of corresponding polyimide blend films obtained by experiment. The immiscible polyimide blend fihns containing nano-/micro-sized BN with vertical double percolation structure were prepared. The result indicated that the thermal conductivity of polyimide blend film with 25 wt% nano-sized BN reached 1,16 W/（m·K）, which was 236% increment compared with that of the homogenous film containing the same BN ratio. The significant enhancement in thermal conductivity was attributed to the good phase separation of polyimide matrix, which made the inorganic fillers selectively localized in one continuous phase with high packing density, consequently, forming the effective thermal conductive pathway.
基金supported by the National Natural Science Foundation of China (Grant No. 41790433)NSFC-ICIMOD (Grant No. 41661144041)+1 种基金Key Research and Development Projects of Sichuan Province (2017SZ0041)CAS "Light of West China" Program
文摘Some of the remarkable characteristics of natural landslides, such as surprisingly long travel distances and high velocities, have been attributed to the mechanisms of frictional heating and thermal pressurization. In this work, this mechanism is combined with a depth-averaged model to simulate the long runout of landslides in the condition of deformation. Some important factors that influence frictional heating and thermal pressurization within the shear zone are further considered, including velocity profile and pressurization coefficient. In order to solve the coupled equations, a combined computational method based on the finite volume method and quadratic upwind interpolation for convective kinematics scheme is proposed. Several numerical tests are performed to demonstrate the feasibility of the computational scheme, the influence of thermal pressurization on landslide run-out, and the potential of the model to simulate an actual landslide.
文摘hi this paper, the non-linear finite element method had been applied to calculate the thermal stress evolving process of the large-scale bearing roller during heating process of final heat treatment. It was found that two stress peaks appeared during heating process and the second stress peak was higher than the first. If the preheating time was elongated, the second stress peak was reduced distinctly. Therefore, the pre-heating time should be elongated suitably to ensure safety in the practical manufacture process.
文摘To decrease thermal stress during laser metal deposition shaping(LMDS)process,it is of great importance to learn the transient thermal stress distribution regularities.Based on the“element life and death”technique of finite element analy- sis(FEA),a three-dimensional multi-track and multi-layer numerical simulation model for LMDS is developed with ANSYS parametric design language(APDL)for the first time,in which long-edge parallel reciprocating scanning paths is introduced. Through the model,detailed simulations of thermal stress during whole metal cladding process are conducted,the generation and distribution regularities of thermal stress are also discussed in detail.Using the same process parameters,the simulation results show good agreement with the features of samples which fabricated by LMDS.
基金National Key Research and Development Program of China(No.2017YFB0701802)NSFC(Nos.51504148 and U1760204).
文摘The influences of superheat and cooling intensity on macrostructure and macrosegregation of one new kind duplex stainless steel(DSS)were studied.Thermal simulation equipment was applied to prepare samples,which could reproduce the industrial processes of DSS manufactured by a vertical continuous slab caster.Macrostructure and macrosegregation were analyzed using the digital single lens reflex and laser-induced breakdown spectroscope(LIBSOPA-200),respectively.The percentage of both chill zone and center equiaxed zone increases with the superheat decreasing,while that of the columnar zone decreases.There is only equiaxed grain existing as the superheat is 10 and 20℃.The lower the superheat is,the coarser the gain size is.High cooling intensity in mold could remarkably decrease the chill zone length and refine the grains in chill zone and center equiaxed zone.The influences of cooling intensity on macrosegregation are greater than those of superheat.The macrosegregation of Si,Mn and Cr is slightly dependent on superheat,while that of Cu,Mo and Ni changes greatly with superheat increasing.
文摘A new reliable thermal simulation system for studying solidification of heavy section ductile iron has been developed using computer feedback control and artificial intelligent methods. Results of idle test indicate that the temperature in the system responses exactly to the inputted control data and the temperature control error is less than ±0.5%. It is convenient to simulate solidification of heavy section ductile iron using this new system. Results of thermal simulation experiments show that the differences in nodularity and number of graphite nodule per unit area in the thermal simulation specimen and the actual heavy section block is less than 5% and 10%, respectively.
文摘Using an artificial intelligent instrument and a computer feedback control method, a new thermal simulation systemis studied. Based on numerical simulation of casting solidification, a sample in the new system successfully simulatedthe solidification of heavy section ductile iron. The results show that the new thermal simulation system is accurateand reliable. Not only cooling curve but also graphite in the center of the thermal sample and the heavy sectionductile iron is identical. Realization of accurate thermal simulation of solidification in heavy section ductile iron willbe helpful for studying formation mechanism and controlling graphite degeneration in heavy section ductile iron.
基金supported by the National Key R&D Program of China(No.2017YFB0406204)the National Natural Science Foundation of China(No.51973002)University Institution of High Performance Rubber Materials of Anhui Province.
文摘Stretched polyethylene(PE)fibers are found to have super high thermal conductivity,while the bulk of polyethylene is usually thermal insulating even for those with high crystalline degree.A molecular dynamic simulation is deliberately carried out to examine the relationship between chain configuration and thermal conductivity of polyethylene.In this simulation study,independent and interacting PE chains being stretched are compared with the aim to find out the effect of stretching on thermal conductivity of PE.Various crystallization conditions for PE bulk are considered.It is found that heat transports predominately along the covalent chain rather than across chains in PE crystals.Our simulation study helps to understand experimental findings on thermal conductivity of PE at different states.W e also predict that amorphous PE may be super thermally conductive if chains are strictly stretched along heat flux.
文摘The relationship between the t8/5 and micro-hardness, impact toughness in the heat affected zone （HAZ） of ASME SA213-792 at peak temperature of 1 350 ℃ was studied by thermal simulation. The result shows that the micro-hardness of HAZ rises at the beginning and then decreases with increasing of t8/5 , whereas the impact toughness presents reverse trend. The distribution of precipitates in substrate has great influence on the impact toughness of HAZ. When the t8/5 is 40 s, chain-like precipitates lower the impact toughness of HAZ seriously.
基金supported by the National Science and Technology Major Project of China(Grant No.J2019-VI-0004-0117)the State Key Laboratory of Special Rare Metal Materials(No.SKL2021K002)Northwest Rare Metal Materials Research Institute Ningxia Co.,Ltd.
文摘K439B nickel-based superalloy is a new type of high-temperature material.There is insufficient research on its constitutive equations and numerical modeling of thermal stress.Isothermal tensile experiments of K439B superalloy at different temperatures(20°C-1,000°C)and strain rates(1.33×10^(-3)s^(-1)-5.33×10^(-3)s^(-1))were performed by using a Gleeble-3800 simulator.The elastic moduli at different temperatures(20°C-650°C)were measured by resonance method.Subsequently,stress-strain curves were measured for K439B superalloy under different conditions.The elastic-viscoplastic constitutive equations were established and the correspongding parameters were solved by employing the Perzyna model.The verification results indicate that the calculated values of the constitutive equations are in good agreement with the experimental values.On this basis,the influence of process parameters on thermal stress was investigated by numerical simulation and orthogonal experimental design.The results of orthogonal experimental design reveal that the cooling mode of casting has a significant influence on the thermal stress,while pouring temperature and preheating temperature of shell mold have minimal impact.The distribution of physical fields under optimal process parameters,determined based on the orthogonal experimental design results,was simulated.The simulation results determine separately the specific positions with maximum values for effective stress,plastic strain,and displacement within the casting.The maximum stress is about 1,000.0 MPa,the plastic strain is about 0.135,and the displacement is about 1.47 mm.Moreover,the distribution states of thermal stress,strain,and displacement are closely related to the distribution of the temperature gradient and cooling rate in the casting.The research would provide a theoretical reference for exploring the stress-strain behavior and numerical modeling of the effective stress of the alloy during the casting process.
基金Supported by the National Environmental Protection Bureau of P.R.China(Huan-Ke-Ke,1997,No.006,Project 14),China-Japan cooperative project:"Research on energy savings and alleviating environmental burden in petroleum enterprises"of Institute of Industrial
文摘Internal thermally coupled distillation columns (ITCDIC) are the frontier of distillation energy saving research. In this paper, a novel energy saving model of ideal ITCDIC and a simulation algorithm are presented,upon which a series of comparative studies on energy savings with conventional distillation columns are carried out. Furthermore, we present an optimization model of ideal ITCDIC, which can be used to achieve the maximum energy saving and find the optimal design parameters directly. The binary system of benzene-toluene is adopted for the illustrative example of simulation and optimization. The results show that the maximum energy saving of ITCDIC is 52.25% (compared with energy consumption of conventional distillation under the minimum reflux ratio operation); the optimal design parameters are obtained, where the rectifying section pressure and the feed thermal condition are Pr=0.3006 MPa and q=0.5107 respectively.
文摘Based on the chasteal nucleation theory, the kinetic precipitation model of carbon - nitride particles in weld HAZ is proposed. Using the model,welding simulation technology and the quantitative metallo- graphic analysis,the precipitation transformation temperatue (PTT) curve is obtained.The data from the simulated welds are in good apreement with the value that the PTT curves predicated.
基金This study was financially supported by the National Key Research and Development Program of China(No.2020YFB2008302).
文摘In the casting process,in order to compensate for the solidification shrinkage to obtain higher dimensional accuracy of the casting,it is often necessary to modify the original design of castings,and a suitable compensation method has a decisive impact on the dimensional accuracy of the actual casting.In this study,based on solidification simulation,a design method of reverse deformation is proposed,and two compensation methods,empirical compensation and direct reverse deformation,are implemented.The simulation results show that the empirical compensation method has problems such as difficulty in determining the parameters and satisfaction of both the overall and local accuracy at the same time;while based on the simulation results for each node of the casting,the direct reverse deformation design achieves the design with shape.In addition,the casting model can be optimized through iterative revisions,so that higher dimensional accuracy can be continuously obtained in the subsequent design process.Therefore,the direct reverse deformation design is more accurate and reasonable compared to empirical compensation method.
