基于Phoenics的稻谷通风过程水分分布模拟初探

通过改进Phoenics软件中的水分、热量和动量控制方程,并引入呼吸产生的水分源项,建立了通风过程中稻谷堆三维水分传递控制方程,可用于研究通风过程中稻谷堆内热湿传递规律。以小型测试平台数据与文献中的高大平房仓通风试验数据为基础,通过编写和导入用户自定义程序(Q1),采用有限体积元法对稻谷堆机械通风过程的水分、热量和动量方程求解。数值模拟研究结果显示,在网格数量较少的情况下,粮堆平均水分预测值仍可与实测值基本吻合,表明机械通风降水过程中稻谷的呼吸作用不可忽略。     

氧气高炉多流体数值模拟与分析

为研究不同氧气高炉操作流程及操作参数对高炉内部过程产生的影响,预测氧气高炉流程各参数的变化规律,基于多流体理论、冶金传输原理、冶金反应动力学与热力学理论以及计算流体力学建立了普通高炉多流体模型,并在此基础上修改边界条件及内部相关参数,建立氧气高炉多流体数学模型。通过建立的模型分别对普通高炉和气化炉氧气高炉(GF-FOBF)流程中的氧气高炉进行了模拟计算,得到两种工艺流程下高炉内温度场、浓度场和速度场等典型参数的分布情况。通过对计算结果的对比,分析了氧气高炉操作条件下炉内状态的主要特征和相对于普通高炉发生的变化,发现氧气高炉内部速度场、温度场均发生变化,特别是气相组分的均匀分布问题明显。本模型可为氧气高炉流程试验及流程开发提供参考。     

三维轴对称功能梯度材料瞬态热传导问题的自然单元法

为了更有效地求解三维轴对称功能梯度材料瞬态热传导问题,对无网格自然单元法应用于此类问题进行了研究,并发展了相应的计算方法。基于几何形状和边界条件的轴对称性,三维的轴对称问题可降为二维平面问题。为了简化本质边界条件的施加,轴对称面上的温度场采用自然邻近插值进行离散。功能梯度材料特性的变化由高斯点的材料参数进行模拟。时间域上,采用传统的两点差分法进行离散求解,进而得到瞬态温度场的响应。数值算例结果表明,提出的方法是行之有效的,理论及方法不仅拓展了自然单元法的应用范围,而且对三维轴对称瞬态热传导分析具有普遍意义。     

槽式太阳能集热器传热模型及性能分析

槽式太阳能集热器一维和二维传热数学模型是一组非线性代数方程,为改进求解的稳定性和计算精度,将槽式太阳能集热器一维和二维传热模型的求解看作有约束优化问题,建立了集热器传热过程求解的有约束优化数学模型,应用MATLAB软件优化函数fmincon进行求解。分析了传热流体入口温度及太阳能辐射热流密度变化对集热器性能的影响。采用fmincon函数求解集热器传热过程,计算速度快,计算过程稳定。分析表明,传热流体温度变化对集热器效率的影响大于太阳能辐射热流密度对集热器效率的影响。     

土体固结与溶质运移三维耦合模型

考虑堆场上覆堆积体自重引起的土体固结与溶质运移的耦合效应已成为环境土工领域中的热点问题。在Biot固结理论和溶质运移理论相结合的基础上,以孔隙率作为耦合参量,将固结方程与运移方程相联系,考虑土体固结对溶质运移模型参数的影响,建立了溶质在固结变形土体中运移的三维耦合模型。采用多场耦合有限元软件COMSOL Multiphysics对模型进行了数值求解。数值模拟结果表明,土体固结变形对溶质运移过程具有较强和持久的阻滞作用,导致溶质运移深度以及污染羽范围的减小,在模拟运移20 a时,运移距离减小率已高达27.75%,且随着时间的增加而逐渐增大;溶质在水平方向的迁移距离不可忽略,随着横向水力梯度的增大而增大。     

苹果花序几何造型及可视化研究

为了实现对苹果花及花序三维形态结构的交互设计、几何建模和真实感现实,提出了精确描述苹果花序三维形态结构的数学模型及可视化方法。通过对苹果花及花序形态结构的观测分析,分别提出了描述花柄、花托、花萼、花瓣、雄蕊和雌蕊三维形态结构的数学模型,并提取了模型的控制参数;进一步整合苹果花及花序的拓扑结构信息,实现了苹果花及花序的三维重建。为了增强花的真实感,提出了花柄、花托和花萼上绒毛的生成方法。结果表明,该方法可控性强,易于操作,可以精确重构出苹果花和花序的三维形态,实现对开花过程的可视化模拟,具有较强的真实感。     

水稻叶曲线特征的机理模型

通过对水稻叶片的受力分析，推导了叶曲线方程，并进行了影响系数的参数化和方程求解。对叶曲线方程的灵敏度分析表明，方程较好地体现了叶长、叶宽、叶形、比叶重和叶片形变系数等参数对叶曲线的综合影响，与生产中水稻株型特征变化相一致。进一步利用三维数字化仪获得的不同品种类型水稻拔节期和孕穗期叶脉空间坐标试验数据对叶曲线方程进行了模拟分析，结果表明叶曲线方程可以合理而可靠地定量描述水稻叶曲线特征的动态变化规律。     

冷却干燥通风过程中粮仓内热湿耦合传递的数值模拟

基于多孔介质传热传质的理论,建立了一种冷却干燥通风过程中粮仓内热湿耦合传递的数学模型。借助数值模拟的方法,对冷却干燥通风过程中粮仓内温度和水分的变化进行了模拟研究,得到了冷却干燥通风过程中粮堆内部热量传递和水分迁移的基本规律。     

洪泽湖农场土壤速效钾含量的地统计学和GIS分析

为了探索江苏省洪泽湖农场土壤速效钾的空间分布规律,精确衡量其土壤速效钾的供应能力,通过网格取样方法、利用GPS定位取得该农场的180个耕层（0~20 cm）土壤样品,应用地统计学分析方法进行实验变差函数的计算和最适合模型的拟合,得出土壤速效钾最好的理论模型为球状模型,随后用普通克立格估值方法绘制了土壤速效钾的空间分布图。通过对不同阶数趋势的土壤速效钾克立格（Kriging）插值误差的综合比较,表明其趋势效应参数应选取二阶。克立格估值标准差（KSD）作为内插象素值的标准差,为提高速效钾的制图精度提供了有用的信息。应用地统计方法和GIS技术研究土壤养分的空间分布规律、衡量土壤养分的供应能力,其方法和结果对于在农业生产中合理施肥、探索发展精确农业、农业可持续发展等方面都有重要的参考价值。     

考虑谷物呼吸的仓储粮堆热湿耦合传递研究

粮食作为生物性多孔介质,具有呼吸特性。一般粮食收获后,大部分时间在密闭不通风状态下存储。以粮堆内局部热湿耦合传递过程作为研究对象,分析了不通风状态下的圆筒形粮仓在自然对流条件下由于温度梯度影响而产生近似冬夏季工况的温度分布和水分转移,借助多物理场数值模拟软件(COMSOL)进行数值模拟,将粮食呼吸作用产热、产湿量以热源、湿源项考虑在数学模型中,通过对温度场、水分场的描述指导工程实践。     

A mathematical description of the liquid flows inside blast furnaces

The knowledge of liquid flows in blast furnaces may play an important role in controlling the blast furnace process. Appropriate assumptions are given to represent the main characteristics of the liquid flow in blast furnaces, such as liquid streams being composed of unwetting liquid droplets, inertial force having little effect on the liquid flows, and mass exchange existing along the direction perpendicular to liquid flow. A mathematical model is built to predict the distribution of the liquid flow rate and the liquid flow range in packed beds. The scale of the numerical grid used to solve this model may not necessarily be reduced to the particle level. The predicted results of this model accord well with the observed data. This model is an alternative theory for the simulation of blast furnaces     

氧气高炉工艺研究进展及新炉型设计

从氧气高炉的数学模型、实验室实验以及工业试验角度系统分析了氧气高炉工艺的发展现状及趋势,同时讨论了氧气高炉炉型的设计依据。论述了氧气高炉的静态工艺模型研究需要计算合适的直接还原度和热空区温度,同时应考虑氧气高炉工况下生产率的变化、热损失的变化、风口煤粉的喷吹上限以及N₂的循环积累等问题。指出了多维动力学模型和多目标优化模型中尚需解决的问题,以及氧气高炉数学模型的主要发展方向。结合文献研究中的氧气高炉特点,从炉身高度设计、炉腹角和炉身角设计以及风口设计3方面综述了氧气高炉炉型设计的变化规律。     

Recent Research on Supervision Running State of the Tuyere and Raceway in Blast Furnace

The manipulators pay fully attention to the running state of raceway looked into tuyere peehole in blast furnace in its production process. And it is important for judgement and control the blast furnace. The pulverized coal feeding and burning cases can be supervised by peehole in tuyere. Temperature distribution can be studied by brightness and numerical simulation of pulverized coal combustion. The recent research of temperature examined and supervision technique of the tuyere and raceway in blast furnace are set forth at home and abroad. A method settling supervision and control the state of tuyere and raceway in blast furnace is put forward by coalescent numeric image process technique to numeric simulate two dimensional imaging technique.     

Mathematical Model of Oxygen Blast Furnace with Preheating Gas Injection into Upper Shaft

An One-dimensional mathematical model,based on oxygen blast furnace with preheating gas injection into upper shaft,has been developed to describe the variation of innerdiameter of blast furnace,13 chemical reactions,the heat losses through the furnace wall,the heatexchange and pressure losses between gas phase and solid phase.The characters of oxygen blastfurnace are discussed,The simulated results indicate that the tem perature of burden in creasesthroughout the upper shaft with the incrcasement of the flow and the temperature of preheating gasinjected,and that the effect of the heating-up of burden is not so large when the com positions ofpreheatin8 gas injeetion are changed.The model is contributed to obtain a deeper understanding ofthe oxygen blast furnace process.     

Pretreatment of Coke Oven Waste Water with Blast Furnace Sludge Method and Blast Furnace Sludge Plus Scrap Iron Method

Coke oven waste water is respectively pretreated by blast furnace sludge method and blast furnace sludge plus iron scrap method, the effects of pH and the quantity of materials and treatment time on the removal efficiency of COD are analyzed. The results indicate that blast furnace sludge plus iron scrap method is superior to blast furnace sludge method .The treatment time and pH can greatly affect on the removal efficiency of COD using blast furnace sludge plus iron scrap method. The treatment time after 30 minutes and pH have no remarkable effects the removal efficiency of COD using blast furnace sludge method. The removal efficiency of COD increases with the increase of blast furnace sludge and iron scrap, but the increase rate decreases gradually.     

Optimization and Realization for Sinter and Ore Blending for Blast Furnace

In the ironmaking process, it is essential that sinter and feed of blast furnace are established economically and reasonably. Taking some steel company for example, the best economical condition for feed of blast furnace is comprehensively considered from technologic demand and economic efficiency. According to LP and based on practice and trial, aimed function and confined condition is confirmed, computation programs are made by Matlab while realizing optimization feed. The blast furnace material balance and heat balance are calculated by program with visual interface. Thus, we can directly judge rationality of optimization. The results show that LP is effective method to realize feed of blast furnace.     

Simulation research on oxygen blast furnace ironmaking process

A system simulation mathematical model on oxygen blast furnace ironmaking process is established. Provided that the material composition and the values of necessary process parameters are given, the model can predict the consumptions of raw material, fuel and flux, the quantity and composition of slag, the quantities and components of all kinds of gases, etc. At the condition of 90% stack ore metallization, the calculated results of the model show that when more circulating gas are introduced into the stack, the heat controls the total gas for the stack ore reduction, while when more circulating gas are introduced into the hearth, the reductive components control the total gas for the stack ore reduction. At normal operations with coke rate fixed, the coal consumption linearly increases with the output top gas. When the coke rate is fixed at 200 kg, the minimum value of calculated coal rate is 200 kg or so.     

Advance in Mathematic Model of Solidification Heat Transfer Process in Continuous Casting

The mathematic model of solidification heat transfer process in continuous casting strand is useful for quantitatively analyzing heat transfer in continuous casting process, quality control and process control. The heat transfer in continuous cast strand in crystallizer and secondary cooling zone have been analyzed. The attention has been paid to basic logic and methodology in model building up. Typical methods determing solution condition and parameters for the model have been discussed. Some numerical methods at the present time for solving solidification heat transfer model, such as finite difference method, finite-element method and boundary element, have been investigated comparatively. In the future, working on solidification heat transfer model, which is more practical, and the integration of the control model will play an important role in the development of high efficiency continuous casting technology.     

Mathematical Model of Selective Catalytic Reaction of Nox in Reactor and Its Simulation

As the domestic technology of selective catalytic reduction(SCR) has not been mature.A assembled-parameter dynamic mathematical model is established for the primary chemistry reaction process in SCR reactor.The mass balance equation of the NH3 adsorption-desorption on the catalyzer surface and six gas components,and total energy balance equation in SCR reactor are set up respectively.A dynamic simulation model has developed by using MATLAB simulation tool.The steady calculation for model is carried on.Based on the established dynamic simulation model,two dynamic simulation experiments have been done,which include the simulation experiment of step disturbance about NOx concentration and temperature.The simulation results current is correctl.The analyzed results indicate that the established dynamic mathematical model for SCR reactor is credible,and prove that the simulation model is practical.