Dynamic Process Simulation Research Articles

An investigation on plastic deformation and nanomechanical properties of Cu60Zr40/ Ni80P20 amorphous nanolaminates

This paper aims to investigate the nanomechanical properties of amorphous nanolaminates by using the molecular dynamic (MD) simulation of nanoindentation process. To achieve this goal, two metallic glass (MG) nanolaminates with the arrangement of Cu60Zr40/Ni80P20 (CN type) and Ni80P20/Cu60Zr40 (NC type) were constructed. The MD outcomes unveiled that the NC-type sample exhibited a weaker strength at the loading stage and experienced a sharper relaxation at the end of holding stage. The strain maps of samples also revealed that the plastic deformation in the CN type initiated at the interface of substrate/indenter and was generated into the depth of material with a pear-like shape. On the other hand, the NC-type sample showed an accumulation of strain at the top layer normal to the direction of indenting process. This result indicated that the plasticity evolution occurred with a homogenous mode in the bulk of CN-type nanolaminate.

Modeling of Dynamic Operation Modes of IVG.1M Reactor

This paper presents the results of a calculation code approach providing a solution to the point kinetics problem for the IVG.1M research reactor of the National Nuclear Center of the Republic of Kazakhstan and allowing the simulation of dynamic processes going on during reactor start-ups, including changes in the thermal state of all its elements, reactor regulator displacement, accumulation of absorbers in the fuel, and the beryllium reflector. A mathematical description of the IVG.1M point kinetics model is presented, which provides a calculation of the reactor neutron parameters, taking into account the dependence of reactivity effects on the temperature, changes in the isotopic composition of materials, and thermal expansion of core structural elements. An array of data values was formed of reactivity added by separate elements of the core when changing their thermal state and other reactor parameters, as well as an array of data with the parameters of heat exchange of coolant-based reactor structural elements. These are used in the process of solving the point kinetics problem to directly replace formal parameters, eliminating the need to calculate the values of these parameters at each calculation step. Preliminary calculations to form an array of values of reactivity effects was applied to the reactor by separate structural elements when their temperature changes were performed using the IVG.1M precision reactor calculation model. The model was validated by the reactor parameters in the critical state. Preliminary calculations to form an array of data with the parameters of heat exchange of coolant-based reactor structural elements were performed in ANSYS Fluent software using the calculation model that describes the IVG.1M reactor fuel element in detail. Validation of the developed calculation code based on the results of two start-ups of the IVG.1M reactor was performed and its applicability for the analysis of transient and emergency modes of reactor operation and evaluation of its safe operation limits was confirmed.

Experimental analysis and dynamic simulation of a solar-assisted industrial process using parabolic trough solar collectors under outdoor conditions

Solar heat for industrial processes has gathered much attention and technological vision over time due to energy savings and environmental concerns even though there are various restrictions and complications in integrating solar collector technologies with industry. This study aims to cut thermal energy consumption and anthropogenic gas emissions in bulgur industry by proposing a novel experimental design for a solar-assisted process heat (SAPH) system. An experimental method has been addressed for the food treatment process integrated with parabolic trough solar collectors (PTSCs) and the proposed dynamic model of the system has been simulated for predicting the annual performance. The performance parameters of the individual system components have been analyzed during the days of the experiments conducted. Operational experience gained from the application reveals that the overall system efficiency depends keenly on the collector efficiency of the PTSCs used, load characteristics, and operating conditions. Furthermore, selecting an appropriate size for all heat-exchange devices is a critical parameter to improve the overall efficiency significantly and avert long-term temperature fluctuations. The long-term simulation results reveal that the annual efficiency can be obtained as 20.8 % for the SAPH system and further improved with system optimization.

Study on the influence diffusion of SMEs in open-source communities from the perspective of complex networks.

In the era of digital economy, enterprise research and development (R&D) tends to be open-source. Due to their limited resources, small and medium-sized enterprises (SMEs) can join open-source platforms to get additional creative resources and technical support. In this context, from the perspective of complex networks, the influence diffusion of SMEs after embedding open-source innovation networks is studied in this paper. First, an integrated simulation model including a network model, agent model and innovative diffusion model is constructed. Second, the influence diffusion strategy is proposed considering initial impact, embedding timing and connection mode (same-match and heterogeneous) of the enterprise. Third, the dynamic simulation of the influence diffusion process of SMEs demonstrates that embedding timing has a significant impact. There is no significant difference in the influence diffusion at the early and mature stages in the evolution process of open-source innovation networks. The initial impact of enterprises has a significant influence on the diffusion during the developing period, but the effect on its influence diffusion at the initial and mature stages is not obvious. Finally, in light of experiment results, it is clear that the open-source platform plays an important role on the growth of SMEs as evidenced by the close correlation between the spread of SMEs' influence within the open-source innovation network and the community's stage of development.

Simulation of dynamic process of double bubble coupled acoustic cavitation

In order to simulate the acoustic cavitation process of double-bubble coupling, based on the fluid dynamics governing equation and fluid volume fraction model, this paper proposes a three-dimensional finite element simulation model of double-bubble coupled ultrasonic cavitation in Fluent software, and numerically simulates the dynamic process of double-bubble coupled acoustic cavitation in fluid driven by ultrasonic wave. The nonlinear dynamic characteristics of coupled acoustic cavitation with double bubbles are studied by evaluating the variation of the acoustic field around the cavitation bubble. The results indicate that under the ultrasonic drive, the spherical bubbles gradually widen first to the maximal radius, then shrink swiftly, and finally collapse. There is an interaction force between the paired double bubbles, which inhibits the expansion of cavitation bubbles and increases the bubble contraction time. The ability of the cavitation bubble to converse the energy is strengthened in the contraction stage. Compared with the acoustic cavitation of the single bubble, the pressure inside the bubble is expanded when the coupled double bubble collapses. The analysis results in this paper will provide the reference for the dynamic process simulation of the ultrasonic cavitation bubbles.

Simulation of dynamic processes of shell structures with viscoelastic elements

The paper presents the choice and method of calculating thin-walled structures that adequately reflect deformation in the compensator example. When choosing a design model, the influence of structural elements and their mechanical characteristics on its behavior in various operating conditions is taken into account since sometimes small changes in the design model can significantly impact the design analysis results. The complete design scheme of most designs, particularly the compensator, leads to statically indeterminate systems. Taking into account the energy dissipation in the shell material; the boundary value problems are reduced to a system of ordinary differential equations of the 12th order. The forms of natural oscillations for the first four natural frequencies are given. It is established that the inertia forces acting in the axial direction do not significantly affect the stress-strain state of shell structures.

Generation of parallel colocation difference schemes using the integro-interpolation approach

The issues of development of stable parallel difference schemes of a given order of accuracy, focused on the discretization of differential equations or their systems with concentrated and distributed parameters using an integro-interpolation approach to the generation of calculation coefficients, are considered. The proposed difference schemes improve the efficiency of parallel simulation and optimization of dynamic processes described by evolution equations with distributed parameters. Such equations are characterized by the absence of analytical solutions. The introduction of higher-order derivatives into difference schemes improves the accuracy of the obtained results and equalizes the approximation orders for all calculation points in the block.The proposed approach is universal for obtaining difference equations of various types. The computational formulas obtained on the basis of this approach for multipoint difference equations have less computational complexity and are oriented to implementation in computing systems with a parallel architecture.
 Keywords: integro-interpolation approach, difference schemes, colocation block methods, parallel computing

Dynamic Process Modeling of Topside Systems for Evaluating Power Consumption and Possibilities of Using Wind Power

Norwegian offshore wind farms may be able to supply power to offshore oil and gas platforms in the near future thanks to the expeditious development of offshore wind technology. This would result in a reduction in CO2 emissions from oil and gas offshore installations, which are currently powered predominantly by gas turbines. The challenge with using wind power is that offshore oil and gas installations require a fairly constant and stable source of power, whereas wind power typically exhibits significant fluctuations over time. The purpose of this study is to perform a technical feasibility evaluation of using wind power to supply an offshore oil and gas installation on the basis of dynamic process simulations. Throughout the study, only the topside processing system is considered, since it is the most energy-intensive part of an oil and gas facility. An offshore field on the Norwegian Continental Shelf is used as a case study. The results indicate that, when the processing system operates in steady-state conditions, it cannot be powered solely by wind energy, and another power source is required to compensate for low wind power generation intervals. An alternative would be to store wind energy during periods of high generation (e.g., by producing hydrogen or ammonia) and use it during periods of low generation. Utilizing energy storage methods, wind energy can be continuously used for longer periods of time and provide a suitable constant power source for the studied case. Higher constant power can also be provided by increasing the efficiency of energy recovery and storage processes. Alternatively, these two technologies may be integrated with gas turbines if the required storage cannot be provided or higher power is required. It was estimated that the integration of wind energy could result in noticeable reductions in CO2 emissions for the case study. Additionally, according to the results, the production, storage, and reuse of hydrogen and ammonia on-site may be viable options for supplying power.

Simulation of dynamic processes when a soil-throwing drum meets an obstacle

The problem of combating forest fires is very relevant to this day. The development of machines designed to extinguish and prevent uncontrolled forest fires, especially in waterless areas, is the most important area of scientific research. The article presents scientific research on simulation modeling of the interaction of a soil-marking drum with obstacles of two types: stones and logging residues. For the study, a simulation method was used in the 3D-CAD environment of the SolidWorks Simulation system, which made it possible to conduct a virtual experiment of a solid model and determine the behavior under static and dynamic loads that occur in emergency situations. The purpose of the work was to develop a 3D model of a soil-throwing drum machine for extinguishing and preventing forest fires to conduct simulation studies on a virtual stand to determine the dynamic loads in contact with obstacles of the soil-throwing drum blades based on the created solid model. For the process of studying the soil-marking drum when encountering obstacles in the form of logging residues and stony inclusions, an imitation virtual stand was created. The paper presents the results of the analysis of data obtained on the basis of simulation modeling.

Dynamic Simulation of Continuous Processes in the Labview Environment

Dynamic Simulation of Continuous Processes in the Labview Environment

Dynamic simulation and control of a triple column process for dimethyl carbonate-methanol separation

Dynamic simulation and control of a triple column process for dimethyl carbonate-methanol separation

Simulation of single bubble dynamic process in pool boiling process under microgravity based on phase field method

We use the phase field method to track the gas–liquid interface based on the gas–liquid two-phase flow in the pool boiling process, and study the bubble nucleation, growth, deformation, departure and other dynamic behaviors on the heating surface under microgravity. By simulating the correlation between liquid undercooling and bubble dynamics, we find that the bubble growth time increases with the increase of liquid undercooling, but the effect of liquid undercooling on bubble height is not significant. Meanwhile, the gas–liquid–solid three-phase contact angle and the gravity level will also have an effect on the bubble growth time and bubble height. With the increase of the contact angle, the bubble growth time and bubble height when the bubble departs also increase. While the effect of gravity level is on the contrary, the smaller the gravity level is, the larger the bubble height and bubble growth time when the bubble separates.

Toward multi-granularity spatiotemporal simulation modeling of crowd movement for dynamic assessment of tourist carrying capacity

ABSTRACT Dynamic process simulation and prediction of crowd movement are effective approaches to understanding the complex human behavior system in GIScience. At present, obtaining full-sample individual trajectory data still faces challenges because of privacy and cost constraints, thereby resulting in difficulty solving geographic modeling problems that require full-sample individual data. In this paper, a general model for crowd movement simulation is proposed by taking the dynamic evaluation of tourist carrying capacity as an example. Such method is a multi-granularity coupling model, which considers behavioral process and spatiotemporal heterogeneity of tourists. First, a secrete event-based logic model of tourist behavior is proposed. Second, a social force-based inference method of tourist path is designed. Finally, the simulation and evaluation model of remaining spatial carrying capacity of tourists based on a behavioral dynamic system is achieved. In addition, the correctness and applicability of the model are demonstrated through a case study. The proposed model will positively affect time- and space-sharing analysis and assessment of crowd flow within a specific area of activity.

Optimization of thermal performance of high temperature sensible heat thermal energy storage system for direct steam generation: A simulation work

The high temperature sensible heat thermal energy storage (TES) system for direct steam generation (DSG) has wide prospects in efficiently utilizing waste heat recovery. Improving the charging/discharging efficiency under a large working temperature range is one of the key issues in optimizing the high-temperature sensible heat TES system performance. This paper focuses on the optimal thermal performance of a high-temperature TES system for DSG by using solid graphite for high-temperature flue gas recovery in a gas turbine. The working performance of the high-temperature TES for DSG was simulated by APROS, which is a physics-based advanced dynamic process modeling and simulation software. The effects of the number and mass distribution of thermal storage cell units on the discharge efficiency were investigated. The results show that the effects of cell unit number on discharging efficiency can be neglected when the cell unit number reaches 10. Based on that, an optimized mass distribution based on the local enthalpy matched method was obtained, and the discharging efficiency can reach up to 0.665. Moreover, the thermal performance of the TES system during the charging and discharging process was also analyzed, especially the effects of flow distribution in parallel modules. Further, the performance of TES was analyzed by integrating it into the CCGT start-up process. The results show that the initial charging rate of TES has opposite effects on waiting time and system efficiency for the CCGT start-up process. And a proper initial charging rate for the start-up process of the CCGT system in this work is suggested to be 0.4.

Design and optimization of VOC control process for tail gas in Rectisol unit based on steady state and dynamic simulation

Rectisol wash process(RWP) is a common process in coal chemical purification unit. However, the CO2 product gas and tail gas in the RWP carries volatile organic methanol, which must be controlled to meet the environmental protection requirements. This work develops a steady and dynamic model for the process of water washing tower(WWT) by Aspen Plus, which is used in Rectisol wash tail gas treatment. The effects of the theoretical stage number(TSN) and desalting water flow rate(FRdw) of the washing tower on the methanol concentration in tail gas(cMET) are studied through sensitivity analysis. The optimized TSN and FRdw of WWT are 16 stages and 15 t/h, respectively. The cMET is 4.1 mg/Nm3 under the optimal condition. The internal structure of WWT is optimized. The design of the WWT is verified by the hydraulic results and dynamic process simulation. The results help to efficiently and conveniently implement the control of volatile organic methanol from RWP.

Numerical and experimental study of co-combustion of refuse-derived fuels in a circulating fluidized bed during load change

This study presents a comprehensive dynamic process simulation model of a 1 MWth circulating fluidized bed test facility applied for lignite and refuse-derived fuel co-combustion. The developed dynamic process simulation model describes the circulating fluidized bed riser and the supplying system with a high level of detail considering heat transfer, gas-solid interaction, combustion, and fluid dynamics. The model was first tuned at two steady-state operation points and was then validated by the measured data from a long-term test campaign of the 1 MWth circulating fluidized bed test facility at various loads (60%–80% to 100%). During the load changes, the simulated pressure and temperature profiles along the combustor as well as the flue gas concentrations agree very well with the measurement data. Finally, increasing the proportion of waste-derived fuel in the co-combustion process was investigated to evaluate the flexibility of its use in power generation to further reduce CO2 emissions.

Simulation of Dynamic Rupture Process and Near-Field Strong Ground Motion for the Wenchuan Earthquake

ABSTRACT The 2008 Wenchuan earthquake that occurred in the Longmenshan thrust zone is the most serious natural disaster recorded in China’s densely populated areas over the past few decades. Its northeast-trending principal fault—the Yingxiu–Beichuan fault (YXBCF), has a complex, segmentary-cascaded geometry and was dominated by the thrust slip in the southwest section, while the right-lateral slip in the northeast section. Some previous works believe that there may have occurred a supershear rupture in the strike-slip-dominated northeast section. Here we revisited this earthquake by exploring the dynamic rupture mechanism of the principal fault and showed a hypothetical scenario with supershear rupture occurring in its northeast section. We utilized a 3D curve grid finite-difference method to simulate the spontaneous rupture process of the YXBCF and corresponding near-field strong ground motion. An appropriate focal process is obtained using the trial-and-error method within reasonable parameters, and its related responses are validated by geological investigations and geophysical inversions. Besides, a large hypothetical oblique propagating supershear rupture is shown between Beichuan and Nanba in the northeast section of the YXBCF. Its transition mechanism is related to the Gaochuan–Beichuan conjugated fault from the fault geometry perspective, and belongs to the joint action of fault barrier and free surface. Such a supershear scenario is not rejected by observations and could increase the credibility of the occurrence of supershear rupture in the northeast section of the YXBCF during the Wenchuan earthquake.

Dynamic Sustainable Processes Simulation to Study Transport Object Efficiency

The development of reliability theory has led to the setting of tasks requiring consideration of the efficiency and functional safety of technical objects of transport over the life cycle. The paper demonstrates the possibility of using the universal laws of elastic wave theory to describe natural phenomena occurring in complex dynamic systems, on the examples of solving issues arising in the interaction of rolling stock and the railway track. The accounting of the time component and the ability of elastic waves to propagate energy in time and space allowed considering any interaction process as a chain of processes, incidence-reflection-refraction of force impulses of interaction. Understanding the physics of dynamic processes that occur in objects while performing their intended functions allows developers to improve objects in such a way as to minimize their life cycle cost and maximize their ability to perform their intended functions under different operating conditions. In addition, it allows the expansion of existing methods and approaches to diagnostics of dynamic transport systems. All this is a base for making it possible to develop an innovative and effective tool for engineers and scientists to assess the impact of technosphere transport objects on human habitats.

Development and Testing of a Mathematical Model for Dynamic Network Simulation of the Oil Displacement Process

Multiphase flows in porous media are widespread in nature and various technologies. One of the most common examples of this kind of task is the task of recovering oil from the rock. This article describes a mathematical model of the flow of a two-phase (immiscible) liquid based on a new approach of network hydrodynamics for a highly branched microchannel medium (simulating a porous space in the rock). The coupling of the flow and pressure fields in the network is performed using a well-proven SIMPLE algorithm in CFD problems; this approach allows us to use effective approaches to modeling 3D tasks. Phase transfer over the network is carried out by an explicit method with an adaptive time step. The article presents the results of verification of the model, with analytical calculations and in comparison with the results of experimental studies. As an experiment, the displacement of oil from a microchip (Dolomite: 3200284) simulating a porous medium was simulated. The good qualitative and quantitative compliance with the results calculated and the results of the experiment show the correct functioning of the model.

Имитационная модель силового трехфазного трансформатора бронестержневой конструкции с витым магнитопроводом

Background. One of the areas of industry digitalization is associated with the concept of digital twins, which allow simulating the operation of real devices in various modes. At present, simulation models of a three-phase rod-type transformer have been developed in the MatLab Simulink SimPowerSystem environment. The models can serve as the basis to design a digital twin of a real device. The problem is to find the most universal method for mathematical description of a transformer of unspecified design to develop its simulation model. The purpose of this study is to develop a simulation model of a three-phase shell-type transformer core with a twisted magnetic circuit and to study this model when the transformer is operating in steady and transient modes. Materials and methods. The authors have applied the methods to model electrical circuits based on the theory of ordinary differential equations, a simulation method using the MatLab Simulink SimPowerSystem software package. Results. The structural futures of the transformers with shell-core design and the main assumptions when developing the simulation model have been assessed. A system of nonlinear equations has been developed to find the flows and MMF generated by the windings of the device. A simulation model of a three-phase shell-core transformer with a twisted magnetic core has been developed. It is based on the obtained equations using the Algebraic Constraint block with the Solver function in MatLab Simulink SimPowerSystem. The results of simulation of dynamic processes in the transformer in various modes are presented. Conclusions. The results of the study can be used to design power transformers in engineering companies and under production conditions. It is also possible to use the developed models in case of power transformer operation to analyze the static and dynamic modes of operation of sections of electrical networks.