Dynamic Process Simulation Research Articles

A multi-criteria simulation-optimization coupling approach for effective emergency response in marine oil spill accidents

Effective marine oil spill responses are vital to reduce environmental, societal, and economic damage. This study developed a Multi-Criteria Emergency Response System (MC-ERS) to comprehensively evaluate response efficiency, operational costs, and environmental losses. The proposed system integrates dynamic multiphase simulation of oil weathering and oil cleanup processes and further provides effective planning for multi-stage resource allocation through system optimization. The developed weight-sum model improved the performance of response operations by reducing the complexity of multi-criteria decision-making. Particle Swarm Optimization (PSO) was chosen as the foundational optimization algorithm due to its efficiency in rapid convergence and suitability for complex problems. From extensive comparisons of PSO variants across benchmark functions and inertia strategies, the C-PSO algorithm was developed, demonstrating enhanced optimization performance for MC-ERS. The developed modelling system performance was demonstrated and evaluated through a representative case study. The optimization plan coordinated resource allocation from onshore warehouses to harbors and spill sites, balancing oil recovery efficiency, costs, and ecological losses. Optimized results indicate an oil recovery of up to 76.50% in five days. Additionally, the system cuts costs by 3.45% and environmental losses by 15.75%. The findings enhance the efficiency of marine oil spill emergency response and provide support for such incidents.

Comprehensive study on air-quality impacts from chemical plant flare emissions under planned or emergency shutdown operations†

Chemical plant shutdown (CPS) operations will employ a flare system to combust waste, unwanted, and off-spec gases dumped from process units to protect the plant safety and the local community. However, the incomplete combustion of flare source under CPS operations including plant planned shutdown (PPS) and plant emergency shutdown (PES) will cause considerable air pollution events. Hitherto, quantitative studies on both primary (CO and NO2) and secondary (ozone) pollutant impacts induced by CPS flaring are still lacking. In this paper, the dynamic effect of flare emissions from two types of CPS (PPS and PES) on ambient air-quality impacts will be systematically and quantitatively studied. The study integrates the dynamic process simulation via Aspen Plus Dynamics with the regional air-quality modelling via Comprehensive Air-quality Model with extensions (CAMx). Case studies indicated that the primary pollutants from flare emissions will be significantly diluted due to the atmospheric transportation, and the maximum concentrations of CO and NO2 can respectively reach 119.0 and 11.0 ppb under PPS, and 47.5 and 4.5 ppb under PES. Meanwhile, the increasing height of the flaring stack will decrease CO and NO2 concentrations but increase the ozone concentration under CPS. Furthermore, CPS in daytime periods will greatly promote ozone generations due to the enhanced photochemical reactions under solar radiation. The maximum 1-hr and 8-hr ozone increment can be 16.6 and 7.1 ppb under PPS while 10.7 and 3.3 ppb under PES, respectively. Besides, the decreasing of flare destruction and removal efficiency will increase ozone and CO under PES.

Experimental measurements and numerical modelling of additively manufactured Fe-Si cores

This paper presents experimental measurements and numerical computations for toroidal Fe-Si cores made by means of additive manufacturing (AM). The production technique of the samples is based on laser powder bed fusion (LPBF). Two different approaches, the Jiles–Atherton (JA) model and an artificial neural network (ANN), have been implemented and compared to represent the hysteretic behaviour of the samples made. The models are identified using experimental measurements at quasi-static rate for a bulk toroidal core. Their accuracy and reliability are evaluated by means of a comparison between simulations and measurements for a different data set. Moreover, a specific JA approach is implemented on the finite element scheme to evaluate its usefulness in the simulations of dynamic magnetization processes with not negligible eddy current effects.

Dynamic modelling and simulation of the Graz Cycle for a renewable energy system

Critical atmospheric carbon dioxide levels and, in response, an increasing shift toward variable renewable energy sources causes the need of transient operation for thermal power plants coupled with carbon capture and storage. In this regard, dynamic process simulations are a valuable tool for predicting the cycling performance of power plants. In this study, the proposed Graz Cycle, an oxy-combustion power plant fired with natural gas, is investigated and modelled in (a) the steady-state design-point (i.e., full-load), (b) steady-state off-design (i.e., part-load), and (c) dynamic conditions. At full loads, the Graz Cycle power plant achieves a maximum net plant efficiency of 54.5%, comparable to the performance results of the competing Allam cycle found in relevant studies. In the off-design simulation, considering for the first time compressor component maps with variable inlet guide vanes, the load is reduced down to 50% achieving improved performance results compared to previous studies. The dynamic simulation boils down to a ramp rate analysis and shows that practical ramp rates of 5.55 %/min for load decrease and 18.18 %/min for load increase can be reached. The results show that the high ramp rates of the Graz Cycle enable balancing services to the electrical grid next to clean and dispatchable power generation. In this study, a systematic first-principle modelling approach has been developed with the final aim to evolve dynamic models for oxy-combustion carbon capture cycles, and a first-of-its-kind analysis of the dynamic operation of the Graz Cycle is presented.

Dynamic Analysis and Simulation of Airborne Flexible Net Deployment and Collision Processes

Dynamic Analysis and Simulation of Airborne Flexible Net Deployment and Collision Processes

The Need for Dynamic Process Simulation: A Review of Offshore Power‐to‐X Systems

AbstractThe integration of offshore wind energy into Power‐to‐X (PtX) process chains offers opportunities for the efficient use of renewable energy. This article analyzes different PtX process chain configurations and their adaptation to the offshore environment. However, direct coupling of PtX platforms with fluctuating electrical energy poses major challenges. Dynamic process simulation is presented for analysis of different plant configurations and operating strategies. The article emphasizes the need for interdisciplinary research to consider technological as well as economic and environmental aspects.

Optimizing Industrial Data Analysis: The Convergence of Business Intelligence and Dynamic Simulations in Chemical Process Management

Purpose: The project aims to leverage Business Intelligence integrated with dynamic simulations in the context of Industry 4.0, focusing on the implementation of a system for the dynamic analysis of a chemical reaction process. The system is designed to optimize data analysis and decision-making processes in large-scale industrial settings. Theoretical Framework: In the evolving landscape of Industry 4.0, the effective management of industrial data and processes is paramount. Traditional methodologies often overlook the potential of integrating Business Intelligence with dynamic simulations. This project proposes a novel approach, combining these elements to enhance process oversight and decision-making efficacy. Method: Utilizing PI System AVEVA/OSIsoft for structured data organization, the project implements a Business Intelligence framework applied to the dynamic simulation of a chemical reaction process. This method focuses on creating a harmonious integration of data analysis tools with real-time process simulations, aiming to improve operational efficiency and adaptability. Results and Conclusion: The implementation of this integrated system in a simulated industrial environment demonstrated a notable improvement in process analysis and decision-making efficiency. This indicates a significant advancement in the application of Business Intelligence in industrial operations, particularly in dynamic process simulations. Research Implications: This study underscores the importance of advanced data analysis techniques in modern industrial operations. The results suggest a substantial shift towards more data-driven, efficient, and adaptable process management strategies in Industry 4.0. Originality/Value: This research highlights the innovative application of Business Intelligence in conjunction with dynamic simulations for industrial processes. It showcases a pioneering approach in enhancing data analysis and decision-making capabilities in the context of Industry 4.0.

Physics-Based Modeling and Fluttering Dynamic Process Simulation for Catkins

Flight simulation of catkins using computer technology helps their prevention and control. However, this is a challenging task due to the complex characteristics, and irregular shapes of catkins, while existing methods mainly focus on rain and snow, which are not suitable for catkins. In this paper, we propose a physics-based algorithm for the dynamic simulation of fluttering catkins. Our approach includes an L-system based 3D modeling method for simulating the natural phenomena of the catkin. We consider the motion of wind, free fall of catkins, and the dynamics of catkins under the joint action of attraction between them, while adhering to the physical motion law of catkins. To provide wind force, we first establish a three-dimensional wind field based on Boltzmann’s equation. We then use the kernel function idea to calculate the attraction force between catkins and finally update the position of the catkin. We incorporate the phenomena of collision and adhesion, attraction, and accumulation of catkins while simulating motion states depending on the adjusted wall height and ground humidity parameters. Our approach overcomes limitations of previous models by achieving good simulation while using relatively less code to simulate various realistic motion states. According to our users’ study, more than 71% of users found the simulation results to be acceptable, authentic, and realistic, confirming the authenticity of our simulation. Our method can generate highly realistic effects, significantly improving efficiency by several orders of magnitude compared to manual modeling. In addition, it can effectively simulate the dynamics of catkins in different scales, providing a decision-making reference for catkin control.

Numerical Simulation of Dynamic Processes in the Medium of Fine-Grained Solid Particles

Numerical Simulation of Dynamic Processes in the Medium of Fine-Grained Solid Particles

Dynamic simulation of powder spreading processes toward the fabrication of metal-matrix diamond composites in selective laser melting

A novel method for the integrated production of structural and functional metal-matrix diamond composites is provided by selective laser melting (SLM) in the field of diamond tools. However, the uneven distribution of diamond particles and loose packing density in the powder bed can easily result in poor performance of diamond tools. In this work, a discrete element method model of diamond/CuSn composite powders is developed to simulate blade-spreading processes. It investigates how powder bed quality and particle dynamics are affected by diamond powder physical properties and powder spreading process parameters. The findings reveal that coarse diamond particles exhibit strong force chains at low velocities, whereas contact force chains are weak for fine CuSn particles at high velocities. It shows that diamond particles with irregular shapes have poor diffusivity and spreadability due to the large friction and mechanical locking forces, which causes diamond particles segregation. Therefore, the packing density and uniformity of the powder bed are both improved by reducing the volume fraction and particle size of diamond particles. In addition, the powder bed quality is improved by increasing the powder layer thickness and decreasing the translational speed of the blade, which weakens the shear expansion and jamming of diamond particles. The results have some significance for optimizing powder spreading processes toward the production of metal-matrix diamond composites in SLM.

Friction-induced ignition study of HTPB propellant based on a coupled chemo-mechano-thermodynamic model under ultrahigh acceleration overload conditions

A method is proposed to assess the friction-induced thermal safety of free-cast solid rocket motors subjected to ultrahigh acceleration overload conditions. By measuring the ignition possibility of propellant specimens during the extrusion friction process and determining the reaction kinetics and constitutive parameters, a coupling model considering the thermal, mechanical and chemical effects is proposed. The kinetic parameters of the thermal decomposition reaction and the parameters of the constitutive model are then calibrated accordingly by compression tests covering a large range of strain rates and differential scanning calorimetry (DSC) tests. Experiments on friction ignition are then conducted to validate the developed model at different extrusion pressures and sliding velocity conditions. The results show that the model developed in this work can accurately predict the ignition possibility and temperature distribution of the propellant. Based on this model, dynamic process simulations of a solid rocket motor subjected to an ultrahigh overload of 10000g were performed. Friction primarily occurs at the bottom and side surfaces of the propellant grain, and ignition is more likely to occur at the outer apex of the bottom surface. The temperature rise in the early stages of overload is primarily driven by the frictional conversion of the bottom surface.

Dynamic process simulation of a 780 MW combined cycle power plant during shutdown procedure

The share of variable renewables in power generation is increasing due to the push to reduce emissions, and the flexibility of conventional power plants has become a major concern. There are many ways to increase the flexibility of existing power plants and implement a more flexible system for the future, such as a fast start-up procedure and higher load change rates. In this study, a 2D dynamic process simulation model of a reference combined cycle power plant is presented to increase the flexibility of cyclic operation by investigating, for the first time in the literature, the shutdown procedure using APROS software. The 780 MWel Tambak Lorok reference combined cycle power plant consists of the GE 9HA.02 heavy-duty gas turbine and a three-stage horizontal heat recovery steam generator with reheat. Several steps were considered to improve the accuracy of the developed dynamic process simulation model, including varying the steam leakage to the atmosphere to control how much thermal energy remains in the heat recovery steam generator, changing the shape loss coefficients of the tubes to achieve higher or lower recirculation, and decoupling the reheater and the intermediate pressure drum. The developed model is validated with real data from three different combined cycle power plants in different countries with various capacities. The comparison shows that the developed dynamic simulation model can accurately represent the real behaviour of natural convection in the heat recovery steam generator. The main outcome was to provide detailed information on the shutdown procedure of large-scale combined cycle power plants, addressing the aspect of the development of new start-up strategies to reduce the time required for the start-up procedure.

Evolution of the Interelectrode Gap during Co-Rotating Electrochemical Machining

A new co-rotating electrochemical machining method is presented to machine the complex structure inside annular parts such as flame tubes and aero-engine casings. Due to the unique shape and motion of electrodes, it is difficult to accurately compute the electric field intensity in the machining area. In this paper, the complex electric field model is simplified by conformal transformation, and the analytical solution of electric field intensity is exactly calculated. A material removal model is built on the basis of the electric field model, and the dynamic simulation of the material removal process is realized. The effects of the cathode radius, applied voltage, feed rate and initial interelectrode gap on the interelectrode gap (IEG) and material removal rate (MRR) are analyzed. The simulation results indicate that the MRR is always slightly less than the feed rate in a quasi-equilibrium state, resulting in a slow reduction in IEG. In addition, the final machining state is not affected by the initial IEG, and the MRR in a quasi-equilibrium state is determined by the feed rate. Several comparative experiments were carried out using the optimized processing parameters, in which the MRR and IEG were measured. The convex structures were successfully machined inside the annular workpiece with optimum machining parameters. The experimental results are in good agreement with the theoretical results, indicating that the established model can effectively predict the evolution process of MRR and IEG.

Methods of composition of different approximations in the simulation of dynamic processes

Methods of composition of different approximations in the simulation of dynamic processes

Dynamic simulation and analysis of the phosgene recovery process using absorption under different control scheme

Phosgene was widely used in various industrial processes. The recovery of phosgene from tail gas is important for promoting environmental protection and process optimization. In this study, the solvent absorption method was employed to recover phosgene from tail gas. First, a baseline steady-state simulation of the phosgene recovery system was established and the results showed that 96 % of phosgene could be recovered. Second, a control scheme was developed; a dynamic simulation was conducted to analyze the dynamic performance of the system under different conditions, including system fluctuations and changes in operation. Additionally, technical and economic evaluations as well as an environmental analysis of the system were carried out. The results indicate that the control scheme has significant advantages in terms of resource conservation and a reduction in carbon and wastewater emissions. The findings provide a basis for the design and optimal operation of industrial phosgene recovery systems.

SIMULATION OF UNDEFORMED CHIP FORMED DURING CUTTING FOR INTERNAL CROWN TOOTH BY THE "POWER SKIVING" METHOD

Today, the world's leading enterprises engaged in the manufacture of gear wheels increasingly use the Power Skiving method of cutting the gear crown on the wheel. This modern method allows you to process wheels with an external and internal crown, both spur and helical, as well as cut slots on shafts or hubs. This technology combines elements of turning and milling and ensures a very short production time. However, every year this method is increasingly improved, and in terms of its kinematics it is very complex and requires precise calculations. Determining the exact position of the tool and the workpiece at each moment of time is necessary for synchronizing movements during cutting. The principle of building an undeformed chip when cutting an internal straight-tooth crown by the Power Skiving method is shown. Section parameters for chip sections are obtained. They are the basis for modeling and calculating the values of cutting forces, friction, the necessary work that is needed to eliminate the allowance, heat flows that occur during cutting, the intensity of tool heating, temperature and wear of the tool, simulation of oscillations and dynamic processes. Complete information about the size and shape of the sheared layers, their size in different sections of the tooth at each moment of the cutting time is necessary for the description of various interrelated and interdependent deformation and contact processes. The established regularities of their continuous cyclical change during the revolution of the cutting tool are required for a comprehensive reproduction of the processes that occur during the cutting process of the toothed crown. A complex system of grapho-analytical, mathematical and computer modeling of this process has been developed for such a task. Kinematics is taken into account and the patterns of cutting-forming processes are reliably reproduced. The application of the grapho-analytical method of constructing sections for an undeformed chip is presented, which made it possible to establish its geometry and main characteristics, as well as to obtain a 3D model. Adequate models of chip formation are obtained. Quantitative estimates of parameters for slices in the process of Power Skiving are analyzed.

Dynamic process simulation of indoor temperature distribution in radiant-convective heating terminals

Intermittent heating can achieve energy savings from a temporal perspective and effectively control building carbon emissions in certain regions. Unlike continuous heating, intermittent heating requires heating terminals with low thermal inertia and a fast room heating speed. Simultaneously, ensuring thermal comfort during the heating process is equally important. Based on this, the newly proposed radiant-convective heating terminal has demonstrated certain potential applicability and thus has gained significant attention. However, current research on radiant-convective heating terminals primarily focuses on steady-state studies of experimental terminal heating performance, lacking dynamic studies on indoor environmental fields. Nevertheless, obtaining a complete, accurate, and continuous indoor heating process solely through experiments is challenging. Therefore, this work simulates the heating process of a radiant-convective terminal through the co-simulation approach of Energy Simulation (ES) and Computational Fluid Dynamics (CFD). ES and CFD are complementary, and therefore coupling them can improve accuracy. Specifically, we establish a co-simulation model for radiant-convective heating terminals and conduct simulations of dynamic convection and radiation modes. The accuracy of the co-simulation results is verified through experimental cases, demonstrating that the convection mode has advantages regarding room temperature rise speed and the heating personnel zone. Furthermore, the radiation mode has advantages in thermal comfort during the stable period. Hence, utilizing a radiant-convective heating terminal with a convection-to-radiation sequence is an effective heating strategy that balances energy savings and thermal comfort under intermittent heating requirements.

A Downscaling Method Based on MODIS Product for Hourly ERA5 Reanalysis of Land Surface Temperature

Land surface temperature (LST) is a critical parameter for the dynamic simulation of land surface processes and for analyzing variations on regional or global scales. Obtaining LST with high spatiotemporal resolution is a subject of intensive and ongoing research. This study proposes a pixel-wise temporal alignment iterative linear regression model for downscaling based on MODIS LST products. This approach allows us to address the problem of high temporal resolution but low spatial resolution of the ERA5 reanalysis LST product while remaining immune to the pixel loss caused by clouds. The hourly ERA5 LST of the study area for 2012–2021 was downscaled to a 1000 m resolution, and its accuracy was verified by comparison with measured data from meteorological stations. The downscaled LST offers intricate details and is faithful to the LST characteristics of distinct land-cover categories. In comparison with other downscaling techniques, the proposed technique is more stable and preserves the spatial distribution of the ERA5 LST with minimal missing pixels. The pixel-wise average R2 and mean absolute error for the MODIS view times are 0.87 and 2.7 K, respectively, for cloud-free conditions on a 1000 m scale. The accuracy verification using data from meteorological stations indicates that the overall error is lower during cloudless periods rather than during overcast periods, during the night rather than during the day, and at MODIS view times rather than at non-view times. The maximum and minimum mean errors are 0.13 K for cloud-free periods and −0.98 K for cloudy periods, indicating a slight underestimation and overestimation, respectively. Conversely, the maximum and minimum mean absolute errors are 2.01 K for the daytime and 0.85 K for the nighttime. Therefore, the model ensures higher accuracy during cloudy periods with only the clear-sky LST used as input data, making it suitable for long-term, all-weather ERA5 LST downscaling.

Визуализация тепловых потоков в высокоскоростном течении за ударной волной

The paper presents the thermographic studies of unsteady heat fluxes behind a plane shock wave in the rectangular 24x48 mm shock tube test section. Consecutive panoramic visualization of the heat fluxes plots on streamlined walls after the plane shock wave interaction with a rectangular obstacle fixed on the channel wall are obtained. The duration of the recorded thermal processes is up to 40 milliseconds after the shock wave passage. The heating and cooling of the test chamber walls streamlined by supersonic flow are visualized using the Telops FAST M200 high-speed infrared camera (operating range 1.5 – 5.1 microns) through the quartz windows transparent to infrared radiation. Visualization of the thermal fields were compared with the shadow images and results of 2D numerical simulation of a nonstationary gas dynamic process after the diffraction of a shock wave with Mach numbers M=2.0-4.5.

Research on microscopic contact characteristics of aggregates during compaction of asphalt mixtures

The compaction process is the stage when the skeleton structure and strength of asphalt mixture are developed. In order to explore the strength development mechanism of asphalt mixture skeleton, the microscopic contact characteristics of aggregates during asphalt mixture compaction process were evaluated. Firstly, the CT scanning and image processing techniques were employed to obtain digital images of the asphalt mixture during the compaction process. Then, the processed digital images were reconstructed in three dimensions to achieve dynamic simulation of the asphalt mixture compaction process. A novel index of contact chains was proposed to characterize the different state of aggregate contact within the asphalt mixture, and then, the characteristic parameters of contact chains during compaction, such as the number of contact chains, contact chain length, and contact chain angle, were analyzed. The results showed that for the typical used SMA-13 asphalt mixture, the primary role of 13.2–16 mm grade aggregates in the asphalt mixture was to form the main skeletal structure, and 4.75–9.5 mm and 9.5–13.2 mm grade aggregates provided more than 90% of the contact points for the asphalt mixture. The contact chains formed by the aggregates of 4.75–9.5 mm and 9.5–13.2 mm were the main source of strength of the asphalt mixture. The aggregate was dominated by migrating movements in the early and middle stages of compaction, and rotating movements in the later stages of compaction dominated the aggregate.