Dynamic Modeling and Simulation of 440 t/h Steam-cooled Cyclone Separator for CFB Boiler

A dynamic mathematical model of the steam-cooled cyclone separator in a 440 t/h CFB boiler has been established.Based on the mathematical model,simulation model of the cyclone separator is created with the advanced continuous simulation language(ACSL).The validity of this model has been verified by the simulation experiments and analysis.This model can provide a theoretical guidance for operation and optimal design of the cyclone separator.     

Modeling and Simulation for 440 t/h CFB Boiler Steam/Water System

Dynamic mathematical model,which is based on the character of power-plant boiler system,is established by the means of modularization. On the basis of dynamic mathematical models,simulation model of the object is created with the advanced continuous simulation language(ACSL).The validity of this model has been verified by the simulation experiments and analysis.The simulation model helps to evaluate the influences that the dynamic process in steam/water's side brings to the boiler's operation and have some directive significance to design method of boiler and optimize run.     

Simulation of High Pressure Startu Poil Pum Pof Turbine

Dynamic mathematical model, which is based on the character of the 200 MW tubine lbricating oil system, is established by means of modularization. On the basis of dynamic mathematical models, simulation model of the startu Pprocess of hign pressure startu Poil pum Pis created with the Visual Fortran language. The validity of this model has been verified by the simulation experiments and analysis. The simulation helps to forecast the dynamic characteristic to high pressure startu Poil pum Pand have some directive significance to design method of lubricating oil system.     

二维高炉区域BFC网格生成技术及其Matlab实现

利用数学模型对高炉冶炼过程进行模拟是高炉炼铁新工艺研发的有效方法,网格生成技术是数值模拟过程中重要的前处理过程,是高炉模拟计算的先决条件。生成网格的质量对高炉模型模拟的精度、效率以及收敛性具有重要影响,因此,建立优质的网格对高炉数学模型的求解具有重要意义。文中提出了一种适用于高炉数学模型的适体坐标系(BFC)网格的生成方法,从求解区域的划分、椭圆型方程的转换、椭圆型方程的离散及BFC网格生成步骤等方面进行了研究,并把死料区的边界作为BFC网格计算的边界条件,使数学模型的求解过程得以简化。采用带有源项的泊松方程作为变换方程,网格的正交性和疏密程度便于控制。该网格生成算法原理简单、易于编程、网格生成效率高,生成的网格能够满足数学模型求解的要求。     

Establishment and analysis of dynamic mathematical model for coal gasifier

Based on the analysis of flowing combustion, gasification reaction, and lumped parameter, a three region model is established to predict the temperature and gas components of Texaco coal gasifier. Using mass balance and energy balance equations to each zone, the model takes account of gas solid two phase flow, coal pyrolysis, radiation heat transfer, and heterogeneous and homogeneous kinetic chemical reactions. Based on the model, a program is developed for dynamic and static simulation. After parameterization and simulation analysis, some important trends and conclusions are attained. Because the model can accurately predict the temperature and gas components in jet region, it has widespread engineering application value.     

STATE VARIABLE METHOD FOR DYNAMIC SIMULATION OF HVDC SYSTEMS

A flexible mathematical model used for dynamic simulation studies of HVDC systems which is based on the stale variable method is presented, and the correspongding computer program has been implemented. Generality, easy to use, and suitable to run on microcomputers are the main features of the model and the computer program. Therefore the model is easy to be extended for application. An example is given in the paper to verily the coneclness of the model and the program.     

Modeling and Simulation of a Novel Drive Train for Wind Turbine with Large Capacity

On the basis of a planetary transmission, a novel hydrodynamic speed controlled transmission system for wind turbines with large capacity is presented. The new drive train consists of wind rotors, planet accelerators, hydro-mechanical and synchronous generators. The dynamic mathematical model of the drive train is established. The digital simulation of speed regulation characteristics for hydrodynamic speed controlled system is studied by using Matlab/Simulink. The simulation results show that continuously variable transmission and fixed speed control can be achieved, and the drive train works well in stability and dynamic performances. They can increase the power yield from the wind, smooth the electric power output, and alleviate the load peak in the new drive train .     

The Research and Simulation of the Fuzzy-PID Control System for Ball Mill Pulverizing of Power Plant

This paper focuses on the main problems in the operation control for ball mill pulverizing system, proposes the dynamic mathematical model for the steel ball mill pulverizing system , simulates and analyzes the dynamic character of the system. A Fuzzy-PID controller with on-line self-tuning parameters based on fuzzy control technology is proposed .The simulation results show that the Fuzzy-PID control system can improve the controlling effect and the ability of suppressing disturbances.     

Performance Simulation of EHE for 300MW CFB

With the development of circulating fluidized bed boiler(CFB),the study field of external heat exchanger(EHE) is greater in extent and degree.In order to research the working process of EHE,the model which deals with flow and heat transfer of EHE for 300MW CFB of Dong Fang Boiler Grou PCo.Ltd.is presented.Based on the cell modeling theory,the EHE is divided into several chamber by heating surfaces.The mass and energy conservation equations of each cell have been developed according to some reasonable assumption.The complete mathematical model has been compiled by Fortran and solved by classical Algorithm of Runge-Kutta.The static test and perturbation experiment of simulating model has been performed.The simulation results show that the model has been reached the steady state rapidly,the dynamic responses are reasonable and the modeling presented in the paper is reliable and appropriate.     

Simulation of the Dynamic Performance of CHANASTAR Minicar with Automatic Transmission

According to the AT minicar project of Changan Automobile CO.Ltd.,the system for simulating the dynamic driving mode of the powertrain with Automatic Transmission is established.The engine and hydraulic torque converter are tested,and the character diagrams are protracted.The two parameter shift rule and the driver fuzzy control module are established.On the basis of dynamical equation,the kinetic model of car is established.With the system,the dynamic and economical performances and ten-mode driving status are simulated.The simulation results show that the system can simulate the actual driving status well,the dynamic and economical performances of the minicar basically meet the technical requirements.The theoretic foundation is provided to the project.The foundation of cruise control is constituted.     

Application of Mathematical Experimentation with Computer in Hydraulic Control

Computer mathematical experimentation technology is applied in pressure hydraulic .The non-linear mathematical model of stage mechanical control system is established by the application of computer mathematical software Maple. The computational results agree with experimental data, and precision is satisfied. The mathematical model is the first apply in the control system of stage mechanical elevator. The method has a wide application in computer auxiliary and simulation of mechanical control system.     

EQUIVALENT CIRCUIT METHOD FOR DYNAMIC DIGITAL SIMULATION OF HVDC CONVERTERS

This paper presents a transient mathematical model of the HVDC converters-Equivalent Circuit Method(ECM), which can describe all possible states of converter valves in a simple and explicit way. With the converter model, programs have been implemented for single and double bridge HVDC systems. The results of simulation to the normal and fault operation of HVDC system show that the method is flexible and reliable, and has the advantages of small calculation amount and less computer storage requirments. The programs based on this paper provide convenient, inexpensive and feasible tools for computer dynamic or transient analysis of the HVDC systems.     

Analytic Solution of Anchor Bolts with Dynamic Detection

Sonoprobe method has been applied in non-destructive inspection of anchorage project. Its fundament is that to use dynamic transient excitation for inducing anchor bar's elastic vibration. The flaws in the bar can be estimated or deduced by determining transient response of anchor bar. Based on the theory of elasto-dynamics, in this paper, a theoretical model of acoustic detection of anchor bar has been built up. On the mechanics field, this method means that if information of disturbance resource, boundary conditions and initial conditions has been given, the dominant equation describing medium motion would be established. That is, it leads to the problem of initial value or initial boundary value of hyperbolic type or hyperbolic-diffusibility type equation. Thereby the dynamic response could be solved. As an example, analytic solution of heterogeneous wave equation is deduced in case of bounded region.     

Application of state feedback and observer inmulti-axle vehicle steering system

A 3-degrees of freedom multi-axle vehicle dynamic model is established.Taking account of the practical difficulties for measuring the sideslip,rolling angles and rolling angle speed,a Luenberger observer is designed,and the simulation and analysis of the Luenberger observer are performed.The results show that the Luenberger observer has excellent characteristics in the considered speed range in tracking path.Then,a state feedback controller is designed on the basis of the Luenberger observer,and simulation of a multi-axle vehicle is also carried out.The results show that the performances of a multi-axle vehicle with the proposed control strategy is better than a multi-axle vehicle with front wheel steering strategy,and its control system has fine dynamic characteristic and strong robustness,so multi-axle vehicle with the proposed control strategy can improve vehicle handling stability and security.     

Analysis of shifting control for dry dual clutch system

Aiming at the dry Dual Clutch Transmission (DCT) system, the motor driven dry dual clutch actuator is studied; the characteristic of distortion load for diaphragm spring and the dynamic transient process of the clutch are analyzed. The mathematical model is established for the system using fuzzy control and PI (Proportion Integration) control, and the simulation is carried out for the DCT shifting process. Simulation results indicate that the motor driven dry dual clutch system can meet the need of the shifting process control requirements and guarantee the high performance of DCT system.     

Building Model of Road Roughness

The input model of road roughness is one key element in the study of comfortable performance of vehicle. A model of road roughness, named Partial Wave Adding model, is theoretically analyzed and studied in detail. Based on the mathematical model, digital simulation of road roughness is studied. The simulation results show that the model is an easily actualized model and has universal adaptability.     

Simulation of the penetration rate (ROP) of the air percussion drilling

It is difficult to calculate the penetration rate (ROP) of percussion drilling. In the early research, the empirical or semiempirical formulae of the ROP are derived from the laboratory or field data collected by the researchers. However, the ROP value of the formulae is not as accurate as that in the field. Benefiting from the dynamic model, the geometric structure model and the theory of the roller cone bit, the mathematical model of the hammer bit, the mathematical model of the true bottom hole and the mathematical model between the tooth and the rock of the hammer bit are established. Hence the ROP of the air percussion drilling can be predicted by simulation. Field tests show the models are reliable and the results are coincident with that in the field. The research can help to redesign the hammer bit and optimize the drilling parameters.     

Transmission model of higher-order elliptical bevel gearing and motion simulation for interference checking

Higher-order elliptical bevel gear is a typical form of the noncircular bevel gear transmission.Space spherical coordinate system of the bevel gear meshing is set up based on the meshing theory of space transmission.The varying relationship among the pitch curve,tooth profile and mesh lines are analyzed,and the equation of the gear tooth surface is developed with matrix method based on space coordinate transformation.The basic parameters of the noncircular bevel gear such as transmission ratio,modulus and the number of teeth are designed,and detailed analysis of the influence of the eccentricity on the relevant parameters is carried out as well.By using discrete numerical method and three-dimensional software,the mathematical model of the tooth profile and virtual physical model of the noncircular bevel gear are established,and then simulation on its motion and interference checking are performed.Finally,the approach for design,calculation and generation of the tooth profile is obtained and its correction has been verified by experiment.     

The Numerical Simulation Commercial Software for Secondary Cooling Process in Billet Continuous Casting

A numerical simulation commercial software has been developed by the object-oriented Visual Basic programming language on the basis of the 2D mathematical model of secondary cooling Process in billet continuous casting. Thereby an effective experimenting tool for computer simulation of continuous casting process is gained. By simulation with the software, the caster structures and operating parameters in continuous casting can be designed and optimized. The simulating calculation examples on several casters and its production applications indicate that the commercial software developed has more accuracy, practicability and commonality, as also as simpler operating capability. The simulated results have been successfully applied to the design and production of the high-efficiency modification for several billet casters interiorly.     

春谷种植密度与产量的数量关系及其分析

为了科学预测谷子的适宜种植密度,探索谷子种植密度与籽粒产量的数学预测模型。采用田间小区试验和非线性回归分析的方法,对主要的密度与作物产量的经验模型进行模拟和比较。结果表明,春谷种植密度对籽粒产量具有重要影响。谷子籽粒产量随着种植密度增加呈先升后降的趋势。二次曲线模型是模拟谷子密度与产量关系的最优模型。春播‘冀谷19’与‘冀谷31’的方程式分别为yj19=2725.528+86.885x-0.701x2与yj31=1289.529+131.318x-1.023x2,理论最适密度分别为61.97万株/hm2与64.18万株/hm2。由此得出,本研究确定的数学预测模型,将为春谷生产提供理论依据。