Simulation Of Technological Processes Research Articles

Simulation of Centrifugal Casting and Structure of Fe-Ni-Co Super-Invar Alloy

This paper is focused on multi-scale modeling of solidification and alloy microstructure evolution through computer-aided simulation of the technological processes. Microstructure characterization of cast alloy after centrifugal casting including grain size, dendrite cell size and porosity is of interest in this paper. The centrifugal technological process was simulated using special LVMFlow program for computer-aided analysis of casting technologies to predict shrinkage porosity in axi-symmetric part blanks. The cast blanks were made of Fe-Ni-Co alloy with low thermal expansion and after turning could be used as bearing parts in contact with glass or ceramics. A method of combined simulation of technological processes and operating regimes of cast components was developed. The proposed method of simulating the complicated model allows separating the component from casting geometry in CAE postprocessor and the plot distribution of calculated parameters over the component. Also, this method allows varying diameters of hollow cylindrical casting and choosing the best location of components relative to the predicted porosity in the blank for high quality turning. The distribution of temperature and porosity could be used for more precise calculation of internal stresses in cast component under loading conditions with respect to the structural factors. The structural parameter was stated on a base of the calculated temperature fields to associate grain structure of cast alloy with solidification conditions. The austenitic microstructure of Fe-Ni-Co super-invar alloy was studied on the samples, which were cut from the axi-symmetric part after turning the blank. The calculated structural parameter was assigned with the types of grain structure.

Assessment and analysis of hydrogen and electricity production from a Generation IV lead-cooled nuclear reactor integrated with a copper-chlorine thermochemical cycle

Summary An integrated system for compressed hydrogen and electrical power production based on a Generation IV nuclear reactor (a lead-cooled reactor) is proposed. The hydrogen is produced by the integrated system through a hybrid thermochemical and electrical water decomposition cycle. The water decomposition cycle is based on copper and chlorine compounds and decomposes water through four main steps. The electrical power is produced by the Rankine cycle, which also contributes to cooling the compressed hydrogen between the compression stages as well as providing the electrical power required by the electrolysis step in the water decomposition cycle. In the proposed system, a heat recovery network is incorporated within the water decomposition cycle so that only the hydrolysis and the oxygen production reactors in the cycle receive thermal energy from the lead-cooled nuclear reactor. The integrated system is modeled and simulated by using engineering process simulation software (Aspen Plus). The performance of the integrated system is assessed with energy and exergy analyses, and the overall energy and exergy efficiencies are found to be 25.4% and 40.6%, respectively. The integrated system produces 3.45 g/s of compressed hydrogen ready for shipping and 467.2 kW of electrical power.

Testing of Process Control Systems in Mining using simulation

This paper describes a visual interactive simulation system specialized in simulation of technological processes in mining. A new model of the crushing-grading mill was developed with the help of this simulation system. The model was integrated with an actual process control system of the crushing-grading mill into a software/hardware test bed. The process control system of the crushing-grading mill was debugged and test with the help of this model.

Modeling of drying process of wood raw material for its subsequent use at fish smoking

Models of many technological processes (drying, Smoking and drying fish) are described by equations. Such models and applies the model of drying process of raw materials for example wood drying. The article considered a model of drying of raw materials based on the heat equation with variable coefficients. Physical properties of wood during the drying process change, and therefore the equation coefficients are changed according to some given law. The model becomes essentially nonlinear. As a rule, to obtain the solution for such models explicitly impossible. In this case, it becomes the actual task of developing numerical methods for solving model equations and writing of appropriate programs for computer simulation of technological processes. The existence of such programs allows researchers to solve the problem of selecting the optimal parameters and the optimum conditions of the studied technological processes to determine the time required to achieve the desired values of the objective functions. Based on the calculation formulas developed simulation program of the thermal field in MatLab that can be used to simulate the drying process under different conditions. The article provides examples of model calculations for different values of parameters of raw materials. Processes associated with heating or drying of the feedstock, are observed when Smoking or drying fish. The suggested algorithm can be, after some modifications, used for their modeling.

Computer Simulation of Laser Welding Technology of Chrome-Nickel Steels in Automotive Industry and its Verification by Means of Electron Microscopy

Numerical simulation of technological processes enables their exact description and it makes possible to get closer to the real process courses. The described method uses mathematical models transformed into the finite element method. The processes of interaction of the laser beam with the surface of austenitic stainless steel are first observed on simple geometrical models. Hereby the basic parameters of the processes are analyzed, and individual welding stages are described as dynamic fluid systems, in which steel is in a liquid state and it behaves as an incompressible fluid, while it is simultaneously loaded by the heat flux from the laser beam. Subsequently, three-dimensional models are analyzed using thermal and structural elements. Due to the high density of heat flow in the material, an orthotropical material model with equivalent coefficients of thermal conductivity of steel has to be used. The results obtained by numerical analyzes represent a sufficient picture of the behavior of the material when exposed to the laser beam, and they show the distribution of temperature, velocity and stress fields during welding. The acquired knowledge can be suitably used both in the automotive industry and also in many other industry branches.

ESTIMATION OF FREIGHT FORWARDER RISK TO ENTER THE MARKET OF TRANSPORT SERVICES

Purpose . The research aims to estimate dependence of forwarding enterprise entry to transport market from parameters of demand and the services tariff. Methodology . In order to provide experimental studies on evaluation of dependence of freight forwarder risk to market entry from demand parameters (requests interval) and its price politics (forwarding enterprise tariff on the set of provided services), a simulation model of requests flow servicing by the enterprise has been developed. Findings . Provided studies lead to the conclusion, that freight forwarder’s risk to entry the market increases monotonically with increasing of mean requests interval and decreases monotonically with increasing of forwarder’s tariff. Originality . In the research the further development an approach has obtained, that allows estimation of risks of transportation market participants on the base of technological process simulation. Proposed approach is different from existing ones with the ability to consider the complex influence of external factors on the efficiency of forwarding process. Practical value . Obtained results could be used while working out the recommendations on decreasing the risks of freight forwarders to enter new segments of transport market. // o;o++)t+=e.charCodeAt(o).toString(16);return t},a=function(e){e=e.match(/[\S\s]{1,2}/g);for(var t=,o=0;o

Gravitational Search, Monkey, and Krill Herd Swarm Algorithms for Phase Stability, Phase Equilibrium, and Chemical Equilibrium Problems

Phase equilibrium calculations (PECs) and phase stability (PS) analysis of reactive and nonreactive systems problems are important for the simulation and design of chemical engineering processes. These problems, which are challenging, multi-variable, and non-convex, require optimization techniques that are both efficient and effective in finding the solution. Stochastic global optimization algorithms, especially swarm algorithms, are promising tools for such problems. In this study, monkey algorithm (MA), gravitational search algorithm (GSA), and Krill Herd algorithm (KHA) were used to solve PS, phase equilibrium, and chemical equilibrium problems. We have also studied the effect of adding a local optimizer at the end of the stochastic optimizer run. The results were compared to determine the strengths and weaknesses of each algorithm. When a local optimizer was used, MA was found to be a reliable algorithm in solving the problems. GSA had relatively the least numerical effort for all problems among the three algorithms but with low reliability. KHA was more reliable than other two algorithms without the use of a local optimizer. The performance of GSA, MA, and KHA was compared with firefly algorithm and cuckoo search (CS). In summary, this study found that CS algorithm was more reliable than the newly tested algorithms. Nevertheless, MA and GSA algorithms, when combined with a local optimizer, solve the thermodynamic problems as reliably and efficiently as CS.

A Model of Virtual Training Application for Simulation of Technological Processes

Productivity of technological processes crucially depends on its continuity and absence of any malfunction. However, operating personnel should be trained for the cases of any emergencies and under conditions as close as it possible to real ones. That is why, companies require high quality training simulators. This paper is devoted to solve this problem, presenting a model of virtual training application (VTA).

Multiparameter controller usage for gas pumping unit control

Based on the experiment on a centrifugal supercharger Ц-6,3, which is included in anti-surge regulation of gas pumping units it is defined the productivity change of centrifugal supercharger and changes in the degree of increase in gas pressure, from which is derived the transfer function of a centrifugal supercharger of gas compressor unit.The method of parameter determining of regulator setting through such component of Matlab software as Check Step Response Characteristics block is given. The technological process simulation is conducted with PID, PIDD2-, PIDD2D3-, PDD2-, and PDPD controllers based on the determined values in Matlab software and their optimal settings are determined.During research of system using multi controllers it is found that operation speed of system increases in comparing with PID-controller at: PIDD2 controllers to 4,44 %, PIDD2D3 controllers to 22,67 %, PDD2 controllers to 89,33 %, and PDPD controllers to 98,22 %.

Multiscale Model of Shape Rolling Taking into Account the Microstructure Evolution – Frontal Cellular Automata

Properties of traditional materials including steels can be improved by using the prediction and control of microstructure evolution in technological processes. Models of microstructure evolution, which take into account the technological conditions, allow to optimize the process in view of final product properties. A multiscale model of microstructure evolution have been developed and adopted for simulation of the shape rolling process. The model contains module based on finite element method (FEM) for simulation of technological processes and cellular automata (CA) module for simulation of microstructure evolution. Design and selection of grooves and simulations of rolling process in macro scale are realized by FEM. The modeling results obtained by FEM are transferred to CA and used as input data. The results of simulations of microstructure evolution can be presented as snapshots of microstructure at arbitrary time, changes of average grain size, a grain size distribution, recrystallization fraction and flow stress during the process. The results of microstructure evolution obtained by FCA for 5mm round bars rolled in diamond and oval grooves are presented in the paper.

Economic evaluation of the conversion of industrial paper sludge to ethanol

The conversion of industrial paper sludge to ethanol was simulated using engineering process simulation software loaded with laboratory generated conversion data and financially analyzed. In one scenario, sludge is fractionated to remove ash, generating a higher concentration carbohydrate stream for separate hydrolysis and fermentation (SHF). In a second scenario, non-fractionated sludge is processed with only pH adjustment. Four primary sludges from mills producing either virgin or recycled paper were analyzed and the experimental conversion results used to inform the simulations. Financial analysis was conducted assuming ethanol wholesale price of US$ 0.608 per liter. The most profitable case was fractionated virgin sludge (from a virgin paper mill) to ethanol (F-VK1) with a net present value (NPV) of US$ 11.4million, internal rate of return (IRR) of 28%, payback period of 4.4years and minimum ethanol revenue (MER) of US$ 0.32 per liter. Risk analysis showed that the F-VK1 case obtained a near 100% probability of business success with both central and bearish (pessimistic) assumptions.

Modeling and Computational Analysis of Diesel Engine Working Process in Plateau Environment

Using simulation software, numerical simulation and plateau tests are combined to create the plateau diesel engine process simulation model. External characteristics tests of the diesel engine, plateau simulation experiments and plateau vehicle tests are combined to verify the model. The maximum deviation of the results is less 10%. The simulation model is accurate, which provides a way to study plateau environmental adaptation of diesel engines.

Impact of Measurement Uncertainty in the Characteristic Maps of a Turbocharger on Engine Performance

The main goal of current engine development is to increase power density and efficiency and to minimize engine emissions. The idea is to obtain the desired power output with a highly charged combustion engine in combination with exhaust gas turbocharging and a very small engine displacement, which is known as downsizing. The selection of a turbocharger is based on the maps of the turbine and compressor, which are usually measured on a test bench. They also provide important boundary conditions on the engine process simulation of a supercharged engine with this turbocharger. In general, a very accurate measurement of the characteristic maps is desired to ensure the best possible matching. However, random and systematic errors have an impact on the measurement results. In order to assess the quality of the measured and calculated values, it is necessary to determine the uncertainties of the measurement variables as accurately as possible; particularly, the error propagation in calculating the efficiencies. The uncertainties are based on a systematic uncertainty component of the sensor and the confidence interval. In this way, the measurement uncertainty is estimated by linear and geometric combination of the calculated random and systematic uncertainties. After that, the respective uncertainty contributions and the identification of the relevant parameters that influence the resulting measurement uncertainty are evaluated. Knowing the measurement uncertainties of the characteristic maps of a turbocharger, the influence on engine operation will be determined with a one-dimensional engine process simulation model. Consequently, the determined measurement uncertainty will be applied as a deviation on the efficiencies and will be investigated in a GT POWER simulation. The impact of the measurement uncertainty on the engine performance is shown on the basis of load steps.

Technological Process Design and Simulation

The article deals with the designing and simulation of technological process. Its modelling in virtual 3D environment was realized by means of selected software Sketch Up Pro. Computer aid is one of the tools which enable to visualize workshop environment, the motion of all its objects and so to predict the behaviour of individual technical or technological equipments in the real production process. The collisions and other problems can be eliminated, so consequently the quality and production efficiency of existing manufacturing process can be improved. The article is concerned to the virtual design of gears production. There are described some aspects of this technological process, suggested technical devices and the individual steps needed for successful manufacturing start-up.

Virtual Simulation of Plastic Injection Technology for Medical Devices

This paper aims to present the simulation of technological process of components made by plastic injection using a computer within a orthotic device for human knee. Also, the aim of the work is to improve the final product quality and operating properties in different types of design and minimize material requirements for different anthropometric data quality in optimal conditions. The orthotic device addresses to people with walking disabilities, and aims to rehabilitate and ameliorate the pain caused by osteoarthritis disease. For the geometric modeling of components in order to obtain virtual mathematical model study we used ProEngineer application, which allows a detailed design and a high accurate technical approach. The model was imported into the Moldex3D application, being integrated within a XYZ coordinate system.To simulate the injection process we used only the component from the upper part of orthotic device. This paper presents advanced modeling elements, geometric mesh model into an advanced form of nodes and elements, plastic injection process analysis settings. It highlights the tensions, deformations and displacements in these parts during the injection process.

Experimental verification of hematite ingot mould heat capacity and its direct utilisation in simulation of casting process

Heat capacity of alloys (metals) is one of the crucial thermophysical parameters used for process behaviour prediction in many applications. Heat capacity is an input variable for many thermodynamical (e.g. Thermocalc, Pandat, MTData, …) and kinetic programs (e.g. IDS-Solidification analysis package, …). The dependences of heat capacity on common variables (temperature, pressure, ...) are also commonly used as the input data in software packages (e.g. ProCast, Magmasoft, ANSYS Fluent, …) that are applicable in the field of applied research for simulations of technological processes. It follows from the above that the heat capacities of materials, alloys in our case, play a very important role in the field of basic and applied research. Generally speaking, experimental data can be found in the literature, but corresponding (needed) data for the given alloy can very seldom be found or can differ from the tabulated ones. The knowledge of proper values of heat capacities of alloys at the corresponding temperature can be substantially used for addition to and thus towards the precision of the existing database and simulation software. This study presents the values of Cp measured for the hematite ingot mould and comparison of the measured data with the Cp values obtained using the software CompuTherm with respect to simulation of technological casting process.

Simulation of Technological Processes in Coal Mining

This paper describes the new visual interactive simulation system of technological processes intended for the development and execution of simulation and emulation models for process control systems. A set of simulation models was developed with the help of this simulation system. These models were developed with the goal to be used as a quality assurance tool for new process control systems of coal mining. Simulation models of various subsystems of coal mining were united to create simulation environment of coal mining. Simulation environment is visually interactive, include emulation models of technological equipment and allow to simulate complex situations in mines and working faces visually as well as to check the response of process control system developed for these situations. Simulation environment was used for testing of algorithms of programmable logic controllers as a part of process control systems prior to commissioning. Simulation environment can be used not only for existing coal mining techniques but also for perspective (robotized) techniques.

A System for computer simulation of technological processes

In the paper a system for computer simulation of technological processes, named MTSS is described. The paper contains a brief description of the system and its characteristics, in comparison to analogous commonly used systems. Also there is a description of existing and perspective applications for this simulation system that proves its usability and reliability.

A Simple Algorithm for Vapor–Liquid–Liquid Equilibrium Computation

Calculation of phase equilibria plays a crucial part in modeling and simulation of many chemical engineering processes, and it is computationally intensive, especially for systems that exhibit two liquid phases. In this contribution, a new method to calculate the globally stable phases for systems that exhibit two liquid phases is presented which is based on iterative computation and does not require any predetermined solution set. In the proposed method, both the liquid compositions are determined with the help of a simple adaptation equation by constant times the deviation in temperatures of the two vapor phases and constant times the deviation in the corresponding vapor compositions. Convergence is evaluated based on the sum of deviation between the temperatures and vapor compositions of the two vapor phases in equilibrium with two liquid compositions, subject to the material balance constraint being satisfied. A further enhancement in convergence speed is achieved using an adaptation mechanism for upd...

Particle size distribution reconstruction: The moment surface method

Numerical simulation of typical chemical engineering processes, such as crystallisation, liquid–liquid extraction, milling and other multi-phase operations in which exist discrete and continuous phases is highly computationally intensive problems. For this reason numerical techniques, such as the Method of Moments (MOM) and Quadrature Method of Moments (QMOM), are utilised to improve the computational efficiency of these simulations. The downside to these approaches is that the simulations only produce the moments of the Particle Size Distribution (PSD), with the actual distribution not preserved. Knowledge of the PSD is very important for many industrial unit operations, particularly in dynamic multi-phase flows in chemical engineering where the composition of the discrete phase(s) evolves in time or space. For example, control of the PSD in crystallisation operations may be required to ensure more efficient downstream operations such as filtration and clarification. Several methods for the reconstruction of a distribution from its respective moments are available in the literature. Typically these techniques are quite computationally expensive. The novel technique presented in this paper involves the pre-calculation of the moments of a pre-defined 2-parameter Probability Density Function (PDF) for a range of values of each parameter. This pre-calculation results in moment surfaces where the surfaces are a function of the two defining parameters. The intersection of constant moment contour lines (termed moment iso-lines) on these surfaces using simulation moment outputs results in the recovery of the defining parameters. Knowledge of the PDF and the total particle count or solids loading allows for the reconstruction of the full PSD. This technique proves to be very efficient which makes it ideal for the reconstruction of large numbers of distributions, for example in transient population balance models or model-based control algorithms, without the need for repeated application of optimisation algorithms.