International Journal of Engineering Systems Modelling and Simulation (12 papers in press)
Numerical analysis of non-isothermal walls driven-gas flow
by Mohamed Hssikou, Jamal Baliti, Mohammed Alaoui
Abstract: The gas flow driven by non-isothermal walls effect is studied by both macroscopic and kinetic approaches. In this study, the behaviour of a rarefied and Maxwell gas flow induced by the thermal creep and stresses within a two-dimensional microcavity is investigated using the Direct Simulation Monte Carlo (DSMC) method and the regularised 13-moment equations solution. The upper and bottom walls of the microcavity are linearly heated from the cold and environmental temperature T_- to the hot one T_+. However, the left and right walls are kept at uniform and different temperatures T_- and T_+, respectively. The non-isothermal walls effect, at the vicinity of longitudinal walls, on the macroscopic gas proprieties is clarified for various values of the Knudsen number Kn, rarfaction degree. The agreement between DSMC and R13 results confirms the breakdowns of the classical Navier-Stokes and Fourier (NSF) theory for rarefied gas microflows.
Keywords: R13; DSMC; Thermal creep; microcavity; rarefied gas flow; NSF.
State Dependent Riccati Equation Sliding Mode Observer for Mathematical Dynamic Model of Chronic Myelogenous Leukemia
by Amin Sharafian, Zeinab Ebrahimi Fard
Abstract: In this paper we present a new alternative technique by combination of State Dependent Riccati equation (SDRE) and sliding mode to overcome the problem of state estimation of a natural system. Chronic Myelogenous Leukemia (CML) is one of the most common form of cancer treated with children. The huge number of immune cells impairs the ability of these cells and cause defectiveness of medulla ossium ability to make red blood cells and Platelets. Estimation of effector T-cells and the population of cancer cells in CML could reduce the number and expenses of medical tests for suffering patients. Adopting SDRE technique in line with Sliding mode observer could help us to achieve an optimum observer gain which prevent and reduce the observer system excitation and makes better estimation especially in natural systems such as CML. Moreover, SDRE technique brings certain nonlinear parts of the system to a seemingly linear structure and avoid linearization which reduce the accuracy of system. On the other hand, sliding mode applied to estimate unmodeled nonlinear dynamics, uncertainties and disturbances. Combination of these techniques make a better observer which benefit from both techniques features. Simulation results shows the effectiveness of the proposed observer for state estimation of the CML dynamical model.
Keywords: Chronic Myelogenous Leukemia; SDRE; Sliding Mode Observer; Optimal Observer.
Study on model of greenhouse gas N2O emission flux of rice field in cold region in growing season in water-saving irrigation mode
by Yu Lihong, Wang Mengxue
Abstract: Under the condition of field experiment, three water management modes of control irrigation, intermittent irrigation and flood irrigation were set, a static black-box-gas chromatographic method was adopted for field in-situ observation on N2O emission flux of cold region rice field in the growing season, and optimal single-factor model and interaction model of N2O emission flux of rice in different water management modes in the growing season were established by using test data of 2014. The interaction model can effectively describe the response features of rice field N2O emission flux to soil nitrate nitrogen and temperature coordinated variation better than any single-factor model. The models of the study can be used for estimating N2O emission flux of rice field in the growing season in cold region of China.
Keywords: rice production in cold region; irrigation mode; N2O; model.
Mathematical Modeling and Simulation for Biogas Production from Organic Waste
by Liliana Delgadillo, Mauricio Hernandez, Maximiliano Machado
Abstract: This paper introduces the modelling, simulation of anaerobic digestion process for biogas production from organic waste. Insight on the relevant model parameters is obtained by performing a sensitivity analysis, followed by the estimation of the selected candidates using a Sequential Quadratic Programming algorithm. Calibration and validation of the model is based on experimental data obtained from a pilot-scaled plant, showing that the proposed model is able to correctly predict the Methane production dynamics from few key measurements.
Keywords: Acidogenesis; anaerobic digestion; methanogenesis; sensitivity analysis.
Research on Energy Consumption System of iron and steel enterprise with Bottleneck
by Demin Chen, Lu Biao, Chen Guang
Abstract: For improving the energy utilization efficiency of iron and steel enterprises, a systemic energy consumption analysis method was put forward in accordance with the index decomposition method of the e-p (IDM e-p) model. And this analysis method included that data collection of enterprise; the improvement of the IDM e-p (IIDM e-p) model; partial correlation analysis (PCA) of energy consumption influencing factors in bottleneck location; multiple linear regressions (MLR) modelling in bottleneck position. And then, this systemic analysis method was used in an iron and steel enterprise. The analysis of the model showed that blast temperature and blast volume were key parameters on coke ratio in bottleneck location. The coke ratio decreased by 0.48kg/t when the blast temperature was increased by 1% (2.15
Keywords: the IIDM e-p model; PCA; MLR modelling; Bottleneck location.
CFD modeling of Air Temperature Distribution inside Tunnel Greenhouse in Semi Arid Region
by Maher Dhahri, Sami Ameur, Hana Aouinet
Abstract: In the semi arid region of the southern Mediterranean especially the middle east of Tunisia, one of the main problems of climates is the large diurnal amplitude of temperature, with too low temperature during winter nights and too height temperature during summer day for successful plant growth and development the control of greenhouse environmental parameters is very important. In this work, a computational fluid dynamic software (CFX15.0) was used to study the micro-climate in a 6
Keywords: Greenhouse tunnel; natural ventilation; CFD; Climate heterogeneity;.
Simulation of Ship Seismic Wave Field in Shallow Sea Based on Three - dimensional Staggered Grid
by Xufang Zhu, Bing Yan
Abstract: To find the law of ship seismic wave field in shallow sea, Three-dimensional staggered grid method is adopted. Environmental characteristics of shallow sea and the excitation mechanism of ship seismic wave have been fully considered in this algorithm. Firstly, this algorithm is used to compare wave fields in the YOZ and XOZ planes under three-dimensional environment, which shows that the propagation characteristics of them are basically the same. Secondly, it is used to transform focal depth, which shows that the closer the focus is near to the seabed, the more concentrated the seismic wave signal in the submarine interface propagates along the horizontal direction, and the stronger the surface wave in the wave field; the energy ratio near the focus in horizontal direction is the higher, while the vertical energy ratio is higher. When the center frequency of the focus is transformed, it shows that the lower the center frequency is, the stronger the surface wave signal, and when the central frequency is lower than 10HZ, almost only the surface wave can be observed, when the frequency is higher than 50HZ, the seismic wave signal in the seabed is gradually weakened. At last, the far-field law is observed, which shows that P wave and S wave merge into one wave group, the velocity is somewhere between them, and the surface waves still can be clearly observed due to slow attenuation.
Keywords: Shallow sea; Ship seismic wave; Three-dimensional staggered grid; Simulation.
A Mathematical Model for Scheduling of Production Process and Allocation of Automatic Guided Vehicle in a Flexible Manufacturing System
by Mohammad Mehdi Tavakoli, Hasan Haleh, Mohsen Mohammadi
Abstract: Given that material handling in manufacturing systems is very important, many organizations use automatic guided vehicle (AGV). In recent years, many organizations have intended to have access to an optimal scheduling plan for their manufacturing and transportation system. For this reason, a mathematical model is proposed in this study for scheduling of the production process and AGV's allocation. Production time in any process, setup time, loaded/unloaded trip duration, parking spaces, and the discharge time and loading of products at each work station are considered in the proposed model. Finally, a numerical example is used to explore the proposed model and it will be solved using GAMS software.
Keywords: Flexible Manufacturing System; Automatic Guided Vehicle; Mathematical Modeling; Scheduling.
The comparative research on two equivalent mechanical models of liquid sloshing into tanks
by Di Yu, Jiangwei Chu
Abstract: Using Quasi-Static model, move trajectory of mass center of liquid in the tank was used to solve, found that mass center of liquid trajectory is the same as the tanks length-width ratio of the ellipse. According to the principle of mechanical equivalence, two kinds of impact equivalent mechanical model of liquid sloshing into tank is established, the spring - mass model and the pendulum model, and the two models of relevant model parameters are derived. The simulation result is that the equivalent mechanical model can more accurately describe linear motion phenomenon of liquid sloshing. For tank liquid vibration frequency division, the fluid dynamics simulation results compared with ANSYS FLUENT software under the condition of the corresponding test results, it is concluded that the equivalent mechanical model is more suitable for liquid vibration frequency range. Using the simulated test bench to verify two kinds of equivalent mechanical model, the results show that both equivalent mechanical models can be used to describe tank liquid sloshing phenomenon, but the pendulum model is more suitable.
Keywords: tank truck; roll stability; liquid sloshing; Equivalent mechanical model.
Finite Element Simulation Analysis of Reinforced Concrete Bifurcated Pipe and Surrounding Rock
by Wen-liang MA, Ke-lun WEI
Abstract: Based on finite element method, the calculation model of Luojiao river hydropower station's reinforced concrete bifurcated pipe structure is established, and the finite element simulation analysis of reinforced concrete bifurcated pipe and surrounding rock is carried out. The calculation model takes into account the influence of geological conditions on the structure stress of bifurcated pipe, according to the stress characteristics of bifurcated pipe in construction and operation, ten cases are considered. In order to study reliability and accuracy of calculation model, results of the finite element are compared with the classical analytical solutions, which proves the validity of the finite element model. The results show that the maximum tensile stress of bifurcated pipe is 4.648 MPa in the normal operation, and the stress value is reasonable as the design basis of reinforced concrete bifurcated pipe structure; the maximum circumferential tensile stress of bifurcated pipe's surrounding rock is from 0.2 MPa to 0.8 MPa, the tensile stress value is low, cover thickness of surrounding rock is enough, Luojiao river bifurcated pipe uses reinforced concrete structure is safe and reliable.
Keywords: Hydropower station; Bifurcated pipe; Surrounding rock; Finite element method; Stress distribution.
Study on nonlinear friction compensation control in the electro-hydraulic servo loading system of triaxial apparatus
by Yong Sang, Weiqi Sun, Xudong Wang
Abstract: Nonlinear friction and uncertain disturbance are two of the most important factors affecting the tracking performance and the robustness in the electro-hydraulic servo loading system of triaxial apparatus. In this paper, an Iterative Learning Control (ILC) based Sliding Mode Control (SMC) has been proposed to solve such a problem. A P-type learning function is used to compensate the model of nonlinear friction. The state-space model of the triaxial apparatus is established and the corresponding controller is designed. The controller employs an ILC based SMC of Input-Output Feedback Linearization (IOFL) method to determine the control rule and accomplish the compensation for the nonlinear friction. A Lyapunov method is applied to analyze the condition of convergence in the finite time and the impact acting on the system caused by the control parameters. The simulation results indicate that the tracking performance and the robustness of the system have been remarkably improved.
Keywords: nonlinear friction; triaxial apparatus; uncertain disturbance; Iterative Learning Control (ILC); Sliding Mode Control (SMC).
Electrical Control System of Power Plant Simulation Based on Modular Analysis
by Fan Jing
Abstract: Since the electric of power plant contains unit plant DCS and NCS, the electrical part of power plant simulation can be extended to be simulation under DCS+NSC environment. However, the single-machine of unit plant simulation is longer applicable to infinite system model. Simultaneously, traditional simulation system based on fixed unit is inefficient and difficult to meet the actual needs of users. This article performs intensive study on the electrical modeling and simulation of power plant and establish corresponding mathematical model. Modular analysis is adopted and the core parts of simulation are provided including generator, excitation system and transformer. For different actual problems and analysis tools the generator model gets simplification and practical models of generator are finally established. Using these algorithms, the logic of functional components and the logic of the subsystem are established, and the model of the entire electrical system can also be constructed. By the system model running on simulators, we use related software to simulate electrical system. The data of system model is stable and vivid by parameter adjustment and optimization, so our model is proved to be feasible and to provide theoretical reference for electric running and maintenance.
Keywords: power plant simulation; mathematical model; generator; excitation system; modularization.