International Journal of Engineering Systems Modelling and Simulation (11 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
Abstract: Under the condition of field experiment, 3 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 two estimation models of N2O emission flux of rice in different water management modes in the growing season were established by using test data of 2014. All models were subjected to significance test, and the highly significant level (P<0.01) was met. The models were verified by using test data of 2015, the average prediction error of the models is 17.52%-27.46%, the adjusting correlation coefficient Radj2is within 0.412-0.643, and the model calculation value is relatively well accordant with practical test value. The test shows that: (1) optimal single factor models of N2O emission flux based on nitrate nitrogen concentration of soil are respectively: linear model of control irrigation mode, f= -2.202 N+13.595 (Radj2=0.394); logarithmic model of intermittent irrigation, f= -4.927Ln(N)+ 11.132 (Radj2=0.456); linear model of Flood irrigation, f=-3.099N+12.940 (Radj2=0.442). (2) Optimal single factor models of N2O emission flux based on soil temperature are respectively: logarithmic model of control irrigation mode, f=15.060Ln(T)-37.844 (Radj2=0.359); quadratic term model of intermittent irrigation, f= 0.034T 2-0.471T+1.072 (Radj2=0.462); linear model of Flood irrigation, f= 0.786T-12.563 (Radj2=0.374). (3) For interaction model of N2O emission flux based on temperature and nitrate nitrogen concentration of soil, the optimal model of control irrigation mode is: f=-0.249N 2+14.448Ln(T)-31.909, and the explanatory power is 54.0%; the optimal model of intermittent irrigation is: f= -3.405Ln(N) + 0.014T 2+3.767, and the explanatory power is 63.2%; the optimal model of Flood irrigation is f= -0.140N 2+0.053T 2-1.571N-1.650T+20.183, and the explanatory power is 60.2%. 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 study on speed control of permanent magnet direct-driven system for mining scraper conveyor
by En Lu, Wei Li, Xuefeng Yang
Abstract: A simulation method of speed control based on the load characteristic of the permanent magnet direct-driven system is presented for mining scraper conveyor. Firstly, the mathematical model of permanent magnet synchronous motor (PMSM) is established based on the coordinate transformation theory. Subsequently, the closed loop speed controller of permanent magnet direct-driven systems is designed on the basis of sliding mode control theory and motor model. The chain characteristics of scraper conveyor are described by Kelvin-Vogit model, and the dynamic model of the overall scraper conveyor system is established with distinct element method. Then, according to the coupling relationship between the permanent magnet direct-driven system and the scraper conveyor, the simulation model of the scraper conveyor is established by using MATLAB/Simulink module. The simulation results demonstrate that the permanent magnet direct-driven system can realize smooth starting of the scraper conveyor, and the random load and polygonal sprocket wheel can influence the stability of speed control system.
Keywords: PMSM; Scraper conveyor; Electromechanical coupling; Sliding mode control; Load characteristic.
Modeling, Simulations and Operational Performance of a Stand-Alone Hybrid Wind/PV Energy System Supplying Induction Motor for Pumping Applications
by Mohammed Abuashour, Mohammad Widyan, Tha‘er Sweidan, Mohammed Momani
Abstract: This paper proposes a stand-alone Wind/PV hybrid power system supplying a three-phase induction motor for pumping applications. The nonlinear dynamical mathematical model for all system components is presented which has then been used for numerical simulations at various solar irradiance levels and different motor loading conditions. The system comprises a fixed speed wind turbine driving a Self-Excited Induction Generator (SEIG) terminated by a capacitor bank. A Photovoltaic (PV) array is integrated to the system via DC-DC buck-boost switch mode converter, sinusoidal three-phase inverter and LC filter. The two sources feed three-phase induction motor driving a centrifugal pump. The duty ratio of the DC-DC converter is controlled on the aim of maintaining a constant voltage at the common coupling point of the two generators and the motor. Comprehensive numerical simulations are carried out in order to reveal the robustness and the feasibility of the proposed system. The system performance has firstly been tested by changing the load torque coupled to the motor at certain solar irradiance levels. With a constant load torque coupled to the motor, the performance of the system has been studied after successive step changes of the solar irradiance levels. It is concluded that the system has the ability to run at wide range of solar intensity levels and motor loading conditions. All numerical simulations are executed using MATLAB software.
Keywords: SEIG; Hybrid Wind/PV System; Induction Motor; Dynamical Analysis.
Mathematical Modelling of Morphological Transition and Spot Segregation in Continuously-Cast High Carbon Steel Billets
by Suryanaman Chaube
Abstract: In this work, the Columnar-to-Equiaxed transition (CET) and spot segregation phenomena in continuously-cast (CC) high carbon steel billets are investigated. Casting process is simulated for a 125 mm
Keywords: continuous casting; columnar-to-equiaxed; billet; high carbon; morphology; spot segregation.
Modelling and validation of a novel continuously variable transmission system using slider crank mechanism
by Abd Rahman Muhammad Luqman Hakim, Khisbullah Hudha, Abd Kadir Zulkiffli, Amer Noor Hafizah, Aparow Vimal Rau
Abstract: In vehicle application, transmission system transfers desired torque and speed from the power source to drive the wheels. Continuously Variable Transmission (CVT) system offers a smooth transition of required ratio where it improves the acceleration performance and reduces fuel consumption. Currently, most of the developed CVT system is actuated by an internal hydraulic circuit where compressibility of oil introduces non-linearity to the system causing the difficulty for controlling the response of CVT. Therefore, a new design which is free from hydraulic system is required to overcome the shortcomings in existing CVT without losing its performance. A new type of CVT mechanism is proposed to overcome the drawback in existing CVT design. The proposed CVT system is designed based on belt-driven type which consists of two sets of variable pulley. Each set of variable pulley is actuated by an electric motor using slider crank mechanism. The sectional pulleys are arranged in radial motion which slide inward and outward of the carrier. Then, the mathematical modelling of the CVT mechanism is developed by using Lagrange formulation. The results from this study show that the simulation model of CVT mechanism can produce good performance behavior in following the desired radius position of the real CVT mechanism.
Keywords: model validation; continuously variable transmission (CVT); slider crank mechanism; Lagrange formulation.
Sliding mode control for a wind turbine in finite frequency
by Youssef Berrada, Ismail BOUMHIDI
Abstract: This paper investigates a sliding mode control for a wind turbine in finite frequency (FFSMC). The sliding mode control (SMC) method can be designed for wind energy conversion systems. However, the fluctuations of wind speed perhaps reduce the robustness of the SMC. A dynamic compensator is introduced to design the sliding surface in order to overcome the difficulty of dealing with a fluctuation of wind speed, but the fast change of this fluctuation in certain finite ranges can lead to degrade the compensator performance. In order to solve this problem, a finite frequency approach based on the generalized Kalman-Yakubovich-Popov (KYP) lemma is proposed, and the compensator parameters are obtained in terms of linear matrix inequality (LMI) which can be solved efficiently using existing numerical tools. In the other hand, the reaching law is used to reduce the chattering that is produced by the traditional approach of sliding mode. Finally, the simulation results illustrate the effectiveness of the proposed control strategy compared to a nonsingular terminal sliding mode control.
Keywords: Finite frequency; sliding mode control; reaching law; wind turbine.