Numerical Simulation of Frost Characteristic on Refrigeration System Evaporator

In order to analyze the running performance of refrigeration air conditioning system and confirm thaw periods in reason, frost process and change process of frost thickness of evaporator surface are studied. Based on basic theory and experiential formula of heat transfer process and mass transfer process, the math model of mass transfer of vapor on evaporator outside and growth process of frost are established. Aiming at a sort of finned-tube evaporator, frost process and change process of frost thickness are simulated numerically. The influence of environment parameters is analyzed.     

Self Excitation Simulation for Hydro-Synchronous Generators

The capacity,voltage,and length of modern electric power system are increasing ceaselessly.Synchronous generators will cause self excitation with the help of armature reaction,its stator current and voltage will increase.The self excitation conditions and the transient process are two aspects for studying self excitation.Now,self excitation conditions are mathematical formulas under certain postulate.The model of transient process of self excitation is linear.The conditions of self excitation are presented based on simulation,and the results of self excitation effected by the electromagnetic parameters of hydro generators operating extra high voltage long transmission line are simulated,based on a saturation model of hydro generators.The conclusions are very helpful for operation and design of hydro generators.     

Model Building and Simulation for Subcritical Pressure Boiler

In order to meet the demand of large scale boiler design and operating optimization, this paper establishes the dynamic mathematic model for domestic 600MW subcritical pressure boiler. MMS software is adopted in the whole process from modeling to simulation. This software make process simple and quick. This model is based on modulariza- tion and the comprehensive physical and chemical process in boiler is considered. Simulation result shows that the re- sponses of this model under different disturbance are coincident to mechanics analysis. The simulation result under ste Pdisturbance can be used to analyze unit changes and provide some guide and it also can supply performance reference data to boiler design.     

Forging Process Development of Thrust Cone Based on Simulation Technology

以藁城、黄骅、沾化冬枣为试材,研究了不同产地冬枣采后贮藏过程中的品质变化.试验结果表明,藁城、黄骅、沾化冬枣的冰点分别为-3.5℃、-4.2℃、-3.9℃;在0℃贮藏条件下,随着贮藏时间的延长,不同产地冬枣硬度均随着贮藏期的延长而下降,VC含量逐渐减少,可滴定酸含量在贮藏过程中整体上呈下降趋势,沾化冬枣酸含量最高,藁城冬枣还原糖含量最小,在贮藏过程中变化较大.贮藏结束后各地冬枣硬度差异极显著(P＜0.01),VC含量差异显著(0.01＜P＜0.05),可滴定酸含量差异极显著(P＜0.01),还原糖含量差异极显著(P＜0.01);黄骅地区土壤中平衡的氮、磷、钾配比,适宜的气候条件,导致黄骅冬枣耐贮性优于藁城、沾化冬枣.     

Extensive Noise Control Model for Plastic & Rubber Sulfuration and Simulation

For the problem of precision and real time control in the process of sulfuration,a new control model is put forward.All the noise existing in the sulfuration process are unified as one kind noise named as extensive noise,and the control system is self-adaptive in the process.The purpose of this strategy is to solve the problem preferred.The model comprises of two parts: one is Neutral Networks which deals with the advance sort,the other is dynamic self-adaptive system which is used to find the system's factors.The simulation result of dynamic self-adaptive system shows that this extensive noise controlled model is valid in the process.     

Temperature Filed Ansys Simulation in QuenchingProcess of 45 Teel Part

Nonlinear thermophysics parameters are considered in ansys finite element software, so it can be used to compute temperature in the quenching. The temperature field in quenching process of 45 steel part is simulated by ansys finite element software, and the relationship between temperature of part and quenching time is obtained. Simulation result is correspondent with real process, this method has quick computing speed, and it can optimize quenching technology and select quenching bath. The most of all,this method can supply the temperature condition in computation of thermal stress and residual stress of quenching process.     

Numerical Simulation on Whole Construction Process of High-Rise CFST Structures

The time-changing analysis model for concrete filled steel tubes was established based on the time-changing concrete model of CEB-FIP MC90, in which the interaction between steel tube and concrete core was considered by the restraint conditions of master and slave nodes. The numerical simulation method was developed for analyzing the whole construction process of high-rise CFST structures. A real structure was taken as numerical example, in which the influence of concrete creep and shrinkage as well as construction process was considered. The results of numerical simulation are compared with those obtained from on-site monitoring. It is shown that the concrete creep and shrinkage as well as construction process have big influence on high-rise CFST structures, which should be taken into account in designs and constructions.     

Numerical Simulation of the Solidification Process Under the Effect of Nature Convection

The process of solidification is numerically simulated with control volume method. The authors study the nature convection in the liquid phase and flow pattern of nature convection during the process of solidification. The result of simulation shows that there are the global flow cells inside the liquid phase, and the local circumfluence exists in the global cells. Especially, the authors analyze transformation of the interface between phases under the effect of free convection on the process of solidification.     

Design of Simulation System for Logistics in Steel-making Process

A simulation system for logistics in steel-making process has been developed by analyzing the state of logistics in steel plant, integrating the approach of coloured Petri nets with time and queuing network and using object-oriented methodology. The software functions for building-up simulation model, executing simulation, managing simulations, playing demo, analyzing statistics and online help. The objectives and principles of the simulation software have schematically been introduced. At last, the software is visually validated with measured input data of primary logistics in Vanadium-extracting, Steel-making Plant of Panzhihua Iron and Steel Corporation. A Gantt diagram and statistics of simulation case are included in simulation results and can be used to assist decision-making for scheduling in steel-making process.     

Simulation of nonstationary stochastic earthquake ground motion based on orthogonal Hilbert spectrum

A new method is proposed for the simulation of nonstationary stochastic earthquake ground motion based on orthogonal Hilbert-Huang transform (OHHT) spectra of its sample observations. Orthogonal EMD method is introduced to treat with IMF. OHHT avoids leakage of energy compared with conventional HHT, and it can be used for analysis of nonstationary signal. The average of the Hilbert spectra over the samples is defined as the Hilbert spectrum of the earthquake motion process and used as the target in the simulation of the process. Random Phase is also introduced to simulate nonstationary earthquake. The statistic characteristics function of stochastic process is given in the paper. Simulations of two earthquake ground motion are carried out. The results show that the samples can accurately reflect amplitude and frequency nonstationary of records. Samples and record of same earthquake ground motion process have same statistic characteristics.     

固液混合油辣椒多相流灌装的数值模拟

以固液混合油辣椒多相流的灌装过程为主要研究对象,采用流体力学计算软件Fluent对其灌装过程进行数值模拟,分别对直径为36、48、60 mm的计量缸在灌装过程中的密度场、各相体积分数的分布状况进行研究。数值模拟结果表明:随着灌装机构计量缸直径的增大,灌装流场的密度均匀性变好,高密度和低密度区域明显减少,直径为60 mm的计量缸其固液混合油辣椒多相流流体的各相体积分数和密度分布比其他两种较好,体积分数与初始设定基本吻合,研究结果为灌装装置的结构设计和灌装工艺提供了理论依据。     

Analysis of Numerical Simulation of Seepage Failure and Seepage Feature of Seawall

In order to analyze seepage feature and seepage failure mechanisms of seawall under flood infiltration, a numerical model for saturated-unsaturated and unsteady seepage flow analysis considering soil permeability variation with seepage failure process was established. And the corresponding finite element computation program was made. Numerical simulation of flood seepage for typical section of real seawall was carried out by use of the program. The computed results were compared with the measured results of field test, which shows good agreement. Based on the numerical simulation results, it can be seen that flood seepage of seawall is a saturated-unsaturated and unsteady seepage flow process and seepage failure of seawall is caused by long time flood infiltration under large seepage gradient. Therefore, upon the flood infiltration, seepage failure of the seawall is a very complicated process, which involves soil permeability variation with seepage failure process and saturated-unsaturated/unsteady seepage flow. It is questionable to use the steady seepage analysis method to simulate seepage failure process of seawall.     

Numerical Simulation on Drying Characteristics of a Combined Microwave-convection Process

Combined microwave-convection drying characteristics are investigated by numerical simulation. Combined microwave-convection drying has advantage of swift drying and sterilization. Based on qualitative analyses on the mechanism of combined microwave-convection drying, the differential equations are established and the numerical simulation method is described. The humidity, vapor pressure and temperature, along the radius in a spherical pill, are calculated by the numerical simulation during drying process. The calculation results show the relationship between humidity, vapor pressure, temperature and drying time, and that drying process is greatly influenced by input microwave power. The calculation results are good consistent with the experimental datum.     

Torsional Vibration Simulation Analysis of Drilling String and Rock Bit

In this paper,the method of establishing the torsional vibration model of drilling string and rock bit and the process of simulation analysis are introduced.The interaction between bit and rock and elastic deformation of drilling string in the process of petroleum drilling which caused the torsional vibration of the drilling string and rock bit is main considered in establishing the model.The torsional model is solved by difference method.Based on the models,the simulation analysis software of drilling string and rock bit is designed,and simulation calculation and analysis of the tortional vibration of drilling string and rock bit under different conditions are computed,and the dynamic behavior and kinetics regularity of drilling string and rock bit in drilling are obtained.     

Transient Simulation of Steam-turbine Generator Based on Time-domain

For achieving the high-fidelity simulation of steam-turbine generator on the real-time simulator of coal fired plant, the paper establishs a group of state equations based on Parkg equation, which can accurately describe its transient process. Then a kind of time-saved numerical solution in terms of four-order Runge-Kutta method is proposed through the modified processing to the time-dependent system matrix A and control matrix B. Finally a program is coded to simulate the emergency load process of one 360MW steam-turbine generator, the result indicates that the method of this paper can exactly apply on the generator model of real-time simulator.     

Production Planning Method for Steelmaking-continuous Casting Process Based on Time Backward and Process Simulation

Reasonable production planning effectively ensures smooth operation. According to the analysis of the characteristics of steelmaking-continuous casting production process, a production planning method for steelmaking - continuous casting process based on time backward inference method and process simulation is presented. Production plan meeting certain criteria is rapidly gained by time backward inference method, and is regarded as input of simulation model in steelmaking process. Considering time randomicity in production process and transporting equipment restriction, production plan meeting more restrictive conditions, such as no equipment conflict, continuous casting, and etc, is acquired through simulating. It assures that the plan is carried out in practice. The instance demonstrates the feasibility of the method.     

Design Process Simulation Based On Information Dependency

A modeling method based on DSM is introduced. In circumstance of iterative task, the ways concerning about the input of data,the generation of stochastic variables and the set of the simulation clock are dipicted. While considering the learning curve of activities, the way is studied express the movable process of a single project and then list the corresponding Monte Carlo simulative block diagram .The program based of EXCEL VBA is also written. The result of a given simulative example shows that the method can simulate complex design activities and plan the project in terms of scientific basis.     

Numerical Simulation and Analysis of Control Rod Dropping of Qingshan 300 MW Nuclear Reaction

This paper provides a theoretic basis to analyze the mechanism of control rod dropping and a solution method to solve the process of dropping. The authors analyze the effect of different forces acting on the control rod in detail. A mathematical model is built and a program is written to solve the process of downward motion. Finally, the model and relative coefficients of the model are modified according to the experimental data. The modified model can well simulate the process of dropping of the control rod, which gives a powerful proof to the accuracy of the model.     

Computational Simulation on Temperature Field of Slab Continuous Casting Mold

On the core concepts that the distributing of temperature and solidified slab shell in mold are a stable process, a new method to calculate the temperature field in mold has been promoted. Consequently, a coupling model on fluid filed and temperature field in stable state has also been established. The concept of effective heat capacity is introduced to deal with the latent heat source term from phase transformation. During the programming for computation, the dynamic updating method is also applied to simulate the influence of solidification on physical properties. The resolution results of this model are analyzed and compared with the tested thickness of solidified shell from casting broke out slab, which demonstrates the correctness and applicability of this model to the practical continuous casting process. Additionally, the thickness distribution of solidified shell in slab mold are also studied in detail.     

砂田降雨入渗过程的模拟实验研究

砂田是一种具有综合效能的旱作技术,在干旱半干旱地区得到了不同程度的应用。为了研究砂石覆盖下降雨入渗的规律,笔者进行了室内模拟实验,对土壤水分的动态变化过程进行了研究。结果表明：在模拟降雨过程中,砂石覆盖下土壤的累计产流量一直低于裸土,说明砂石覆盖有利于减少土表降雨产流。砂石覆盖的土壤的各个深度土壤含水率均比裸土对照组要高,表明砂石覆盖有降雨入渗到土壤中。在经过一定时间的降雨后,砂石覆盖土柱中不同深度的土壤含水率变化会趋于稳定,且数值接近,表明砂石覆盖的土壤比裸土更快地进入稳渗阶段。