HEAT TRANSFER STUDIES OF HIGHLY VISCOUS NON-NEWTONIAN FLUIDS IN VERTICAL TUBES BY FINITE ELEMENT METHOD

A numerical method capable is developed for handling steady laminar flow and heat trans-fer of a highly viscous power-law fluid whose density,viscosity,specific heat and thermalconductivity,vary with temperature.The governing equations are found to be continuity,monmentumand energy expressions.Important effects such as varying viscosity,natural convection and viscousdissipation are incorporated in the theoretical model.These equations are being attracted by employing a decoupled finite element method.Galerkin'sprinciple is used to handle the momentum and continuity equations.Consistent(SU/PG)andnon-consistent(SU)streamline upwind methods are employed for the energy equation.Comparisonof calculated results and experimental data shows good agreement.Similar results are obtained withSU and SU/PG methods.Velocity and temperature profiles which provide insights into the processare also given.     

A MATHEMATICAL MODEL FOR LAMINAR DISPLACEMENT OF ONE NON-NEWTONIAN FLUID BY ANOTHER IN HORIZONTAL CONCENTRIC ANNULI

This paper develops a mathematical model and a computational algorithm, which enable the prediction of laminar displacement efficiency in concentric horizontal annuli. Power-law model is used to characterize rheological properties of both displaced and displacing fluids. This model allows a careful investigation of individual effects of various parameters such as fluid rheology, flow geometry and displacement rate on the displacement efficiency. Simulated results demonstrate the dominant influence of rheological properties of displaced and displacing fluids on the laminar displacement efficiency. The model can be used to optimize fluid flow parameters in chemical process designs.     

A MATHEMATICAL MODEL FOR LAMINAR DISPLACEMENT OF ONE NON-NEWTONIAN FLUID BY ANOTHER IN HORIZONTAL CONCENTRIC ANNULI

This paper develops a mathematical model and a computational algorithm, which enable the prediction of laminar displacement efficiency in concentric horizontal annuli. Power-law model is used to characterize rheological properties of both displaced and displacing fluids. This model allows a careful investigation of individual effects of various parameters such as fluid rheology, flow geometry and displacement rate on the displacement efficiency. Simulated results demonstrate the dominant influence of rheological properties of displaced and displacing fluids on the laminar displacement efficiency. The model can be used to optimize fluid flow parameters in chemical process designs.     

碳纤维缠绕复合气瓶爆破压力的有限元分析

本文主要采用有限元法分析复合气瓶的爆破,按最大应力准则和最大应变准则预测爆破压力,并与《DOT CFFC》标准规定的最小爆破压力进行比较,计算误差百分比,由误差百分比分析得出,按最大应变准则预测爆破压力较为接近最小爆破压力,对工程实践有较大的指导意义。     

卧式双轴T型搅拌器在非牛顿流体中的搅拌功率特性

考察了卧式双轴Ｔ型搅拌在非牛顿流体中的搅拌功率与表观雷诺数（Ｒｅ＾＊）、弗劳德数（Ｆｒ）以及加料量的变化关系,实验结果表明：Ｍｅｔｚｎｅｒ常数Ｋｓ随加料量的减少而急剧增加;在层流区域,Ｎｐ．Ｒｅ＝Ｋｐ关系仍然成立且非牛顿流体功率曲线与牛顿流体重合。对实验数据进行关联得到了非牛顿流体搅拌功率准数关联式。     

波纹管非线性特性的有限元分析

根据波纹管运行状态的非线性特性,在非线性有限元理论的基础上,从几何非线性、材料非线性两方面对波纹管进行应变分析,并与电测值进行比较,得到波纹管非线性特性对波纹管研究的影响。     

A THEORETICAL STUDY OF THE EFFECT OF ROTATION ON ANNULAR DISPLACEMENT OF ONE NON-NEWTONIAN FLUID BY ANOTHER IN HORIZONTAL CONCENTRIC ANNULI

This paper presents a theoretical study of the effect of rotation of inner pipe on the laminar displacement efficiency of one power-law fluid by another in horizontal concentric annuli. Simulated results demonstrate a viscosity-reducing effect of the inner pipe rotation, which implies the possibility of promoting a mechanism for turbulent-flow displacement.     

COMBINED FORCED AND FREE CONVECTION IN BOUNDARY LAYER FLOW OF NON-NEWTONIAN FLUID ON A HORIZONTAL PLATE

An analysis is presented to study the effects of buoyancy-induced streamwise pressure gradients on laminar forced convection heat transfer to non-Newtonian fluids from a horizontal plate. Numerical solution of the transformed boundary layer equations has been carried out for different values of the flow behavior index and the buoyancy parameter by means of the local nonsimilarity method. A discussion is provided for the effect of the buoyancy force on the friction factor, the dimensionless heat transfer rate and the details of the velocity as well as temperature fields.     

FINITE ELEMENT ANALYSIS OF ADHESIVE JOINTS IN FOUR-POINT BENDING LOAD

Nonlinear finite element analysis (FEA) was applied to the adhesively bonded Single Lap Joint (SLJ) in bending load. Two adhesives, one stiff and one flexible, with very different mechanical behaviors, and hard steel as adherend with four different thicknesses, were analyzed for the joint configuration. For comparison, experimental work was also undertaken. It was shown that adherend thickness played an important part in the joint performance; while the stiff adhesive gave stronger joint strength when using thick adherends, the opposite was the case for the flexible adhesive when using thin adherends. These results were related to the mechanical behaviors of the adhesives used. It was shown that the results from the FEA and the experimental works were in a good agreement.     

复合材料层合板孔边应力场的有限元计算

纤维增强复合材料具有较高的比强度、比刚度和比模量,在航空航天领域得到越来越广泛的应用.层合板是当前复合材料在工程结构中应用的主要形式.对于含孔的层合板结构,由于材料的各向异性以及孔的影响,其应力分布比较复杂,采用数值解是较好的选择.本文基于层合板的可设计性特点,综合考虑铺层角度、铺层顺序等对层合结构的影响,设计出了一种二十四层对称层合板.以有限元方法为基础,借助ANSYS分析工具,对该层合板含孔结构的孔边应力重点分析,得出了不同铺层角度铺层中应力分布的云图和孔边应力分布曲线.本文结论对复合材料层合板优化设计和带孔层合结构的应力计算具有较好的参考价值.     

用有限元法研究短纤维／橡胶复合材料内应力传递

采用有限元法对短纤维／橡胶复全材料内应力传递和分配规律进行了初步探讨。结果表明：纤维末端的界面剪切应力和纤维中部的拉伸应力均最大，纤维末端仍传递一定的拉伸应力；纤维体积分数越大，纤维末端端应力集中越严重；纤维长径比越大，纤维上的最大拉伸 力也越大，但增幅越于平缓；纤维模量增加，纤维上的拉伸应力集中也增加，但增减缓，基南模量增加，界面剪切应力集中和纤维拉伸应力集中均下降，但剪切应力和拉伸应力的红色     

对FRP筋混凝土桥梁面板承载力性能的非线性有限元分析

为了研究FRP筋混凝土梁面板的承载能力,采用了大型商用软件ABAQUS对Sherif EI-Gamal等的钢混桥梁模型进行了数值模拟。将非线性有限元计算结果同试验结果进行对比分析,非线性有限元的计算结果与试验结果吻合良好。基于数值模准确的分析结果,对结构体系中的压缩薄膜效应进行了分析,并开展了一系列的参数学习,包括混凝土强度、支撑梁刚度以及横隔梁。分析结果表明,压缩薄膜效应对FRP筋混凝土桥面板的承载能力有显著的影响。     

对FRP筋混凝土桥梁面板承载力性能的非线性有限元分析

为了研究FRP筋混凝土梁面板的承载能力,采用了大型商用软件ABAQUS对Sherif EI-Gamal等的钢混桥梁模型进行了数值模拟。将非线性有限元计算结果同试验结果进行对比分析,非线性有限元的计算结果与试验结果吻合良好。基于数值模准确的分析结果,对结构体系中的压缩薄膜效应进行了分析,并开展了一系列的参数学习,包括混凝土强度、支撑梁刚度以及横隔梁。分析结果表明,压缩薄膜效应对FRP筋混凝土桥面板的承载能力有显著的影响。     

ADAPTIVE AND STOCHASTIC FINITE ELEMENT ANALYSIS IN DRYING

The focus of this paper is on the use of new advances in the finite element method to model and analyze drying problems, with emphasis on biological, food and grain materials. It presents the current status of the use of numerical analysis for such process, and emphasizes the need and advantages of incorporating adaptive and stochastic strategies into the finite element analysts. The existing literature on the application of the adaptive and stochastic finite elements is reviewed in conjunction with the relevant advances in this area. A new perturbation-based stochastic methodology far nonlinear and transient drying problems is formulated and presented in detail. The specific application of this new methodology to drying is under development. In conclusion, tracks for future research in this field are proposed.     

ADAPTIVE AND STOCHASTIC FINITE ELEMENT ANALYSIS IN DRYING

ABSTRACT

The focus of this paper is on the use of new advances in the finite element method to model and analyze drying problems, with emphasis on biological, food and grain materials. It presents the current status of the use of numerical analysis for such process, and emphasizes the need and advantages of incorporating adaptive and stochastic strategies into the finite element analysts. The existing literature on the application of the adaptive and stochastic finite elements is reviewed in conjunction with the relevant advances in this area. A new perturbation-based stochastic methodology far nonlinear and transient drying problems is formulated and presented in detail. The specific application of this new methodology to drying is under development. In conclusion, tracks for future research in this field are proposed.     

基于非线性本构关系的有限元计算复合材料层合板的强度

复合材料的桥联模型本构理论考虑了基体材料的非线性特性.本文根据联模型理论编制出用户自定义材料库程序,与有限元软件ABAQUS实现接口,以方便地分析计算复合材料层合板结构的非线性响应与极限强度问题.在限元计算中荷载采用逐步加载的方式施加,最终得到复合材料层合板极限坏时的内力包罗图和应力应变曲线.有限元模拟的结果与桥联模型解析解结果吻合得很好,并且与实验结果相一致.     

玻璃钢板加固混凝土梁界面应力有限元分析

本文对玻璃钢板加固混凝土梁界面应力进行了有限元分析,研究了不同玻璃钢板长度、厚度对界面应力的影响,得到了界面应力随玻璃钢板长度、厚度变化的规律.有限元计算结果与试验结果吻合较好.     

陶瓷全自动液压压砖机有限元分析

本文对陶瓷全自动液压压砖机架（ 包括上梁、立柱、底座） 进行了整体有限元应力分析和单独分析,两者分析结果表明,危险部位的应力吻合,得出的全场应力分布比传统的计算方法更精确更详细,为压机结构整体强度分析提供了重要依据。     

FINITE ELEMENT ANALYSIS FOR LAMINAR FLOW AND HEAT TRANSFER IN FINITE ROD BUNDLES

This investigation deals with the application of finite element method to solve the thermohydraulic problem of laminar fully developed flow in the interior and wall sub-channels of finite fuel rod bundles. A variational principle has been used for the solution of the momentum and energy equations. Wall shear stress and temperature distributions, ƒRe and Nusselt numbers are obtained for the sub-channels of different configurations. The results are compared with solutions generated by collocation and finite difference methods.     

FINITE ELEMENT ANALYSIS FOR LAMINAR FLOW AND HEAT TRANSFER IN FINITE ROD BUNDLES

This investigation deals with the application of finite element method to solve the thermohydraulic problem of laminar fully developed flow in the interior and wall sub-channels of finite fuel rod bundles. A variational principle has been used for the solution of the momentum and energy equations. Wall shear stress and temperature distributions, ?Re and Nusselt numbers are obtained for the sub-channels of different configurations. The results are compared with solutions generated by collocation and finite difference methods.