自动去冒口装置的多执行器液压系统设计

介绍了实现去浇铸件冒口装置的工作原理,根据设计原理和设计要求,提出了一种多执行器顺序动作的液压系统控制方法。分析了液压控制系统各个执行器的控制要求,合理选择及改进设计了顺序控制回路、速度控制回路、锁紧回路、阀控液压缸伺服控制回路等其他的液压回路,各个回路之间相互联系、同时又相互独立。该设计不仅大大提高了系统的自动化程度、稳定性、可靠性,而且提高了系统的可维护性。     

Derivation and validation of a binary multi-fluid Eulerian model for fluidized beds

The paper presents a multi-fluid Eulerian model derived from binary kinetic theory of granular flows, free path theory and an empirical friction theory. The effects of the inter- and inner-particle collisions, particle translational motions and particle–particle friction are included. As the effects due to fluiddynamic particle velocity differences and particle–particle friction are considered, some unconventional terms are produced compared with the previous models. Model validation using the data from Mathiesen et al. (2000) shows that the coupling terms give a stronger and more realistic particle–particle coupling because the effects due to the fluiddynamic velocity differences are considered. The model gives reasonable predictions of the particle volume fraction, particle velocities and velocity fluctuations. The model analysis reveals that the basic particle velocity fluctuations constitute 2 terms: the velocity fluctuations of the discrete particles, and the velocity fluctuations of the continuous fluid flow. Furthermore, the simulation results show that the velocity fluctuations of the continuous fluid flow are dominant in a binary riser flow.     

NUMERICAL SIMULATION OF THE GAS-PARTICLE FLOW IN RISERS I: THE MACRO FLOW BEHAVIOR

The steady gas-particle flow in risers under variant operating conditions was predicted based on a k-ε-k_p-ε_p-Θ two-fluid model, which describes the dense turbulent gas-particle flow by the Eulerian method, considering the turbulence of both gas and particles as well as the particles' collisional effects. Much information on the macro flow behavior in risers, such as the profiles of local particle axial velocity, solids volume fraction, and solids mass flux in different operating regimes was obtained, and the predicted results show satisfactory agreement with experimental data. Further analysis of the predictions gives the comprehension of flow characteristics on the macro scale.     

论乙烯装置裂解炉辐射段炉管整体更换

对乙烯装置裂解炉辐射段炉管的结构、换管原因、整体更换方法及施工程序等方面进行了较为全面的阐述。     

Φ6400mm超大铸钢齿圈制造

拉法基都江堰水泥设备Φ4.8m×52m回转窑Φ6400mm超大铸钢齿圈是目前国内生产的最大的调质齿圈之一。该齿因采用GS—34CrMo4V钢,为三幅板单齿圈结构,其制造不但难度大,而且涉及工序多。本文根据大齿圈热加工制造过程,分析了如何保证内部质量、尺寸精度、铸造及调质变形等技术难点,采取了适当的铸造、热处理工艺和各工序质量保证措施,成功制造了一套特大型齿圈。所生产的齿圈满足拉法基公司、洪堡公司、唐山安装工程公司三方的技术要求。该齿圈的生产技术达到了国内先进水平,为集团公司今后生产同类产品提供了宝贵的技术经验。     

轮形铸铁件浇注系统与冒口联合补缩设计

采用半环形横浇道、内浇道径向引入.在浇注系统的对面安放侧冒口.直浇道、横浇道、侧冒口的大小采用模数计算法确定.用这种浇注系统和冒口联合补缩的工艺形式,生产中型(重85 kg)灰铸铁制动轮和球铁齿轮,消除了铸件缺陷.获得了内在和外在质量都高的轮类铸件,铸件合格品率98%～100%,铸件出品率85%以上.     

利用AutoCAD—AME软件进行铸钢件冒口设计

开发了一套对铸钢件进行冒口设计的软件，此软件利用ＡｕｔｏＣＡＤ—ＡＭＥ软件建造的铸钢件三维几何图形，对铸钢件各个部分的模数、重量、体积和表面积进行计算，并以模数法进行铸钢件冒口ＣＤＡ。此软件的开发对进行基于三维的铸造工艺ＣＡＤ／ＣＡＥ的研究起到了积极的作用。     

铸钢件冒口离开热节动态顺序凝固补缩特性的研究

采用正交设计现场浇注，试验研究了铸钢件冒口离开热节动态补缩特性。结果表明，冒口位置对补缩效果影响显著，铸钢件冒口在离开铸件的几何热节处，实施动态顺序凝固补缩，提高了冒口补缩效率和工艺出品率。在试验条件下，冒口离开何热节的距离为一倍热节圆直径时，补缩效果良好。     

铸件热节变化与冒口位置的分析

热节是铸件凝固慢的节点或区域,可分为几何热节、物理热节、接触热节和流动热节.热节的位置、大小受铸件结构、铸型材质和浇冒口系统的开设位置所影响.冒口的开设应使接触热节、流动热节与几何热节分离.     

Numerical simulation of flow behavior of particles and clusters in riser using two granular temperatures

Cluster in CFB riser significantly affects performance of circulating fluidized beds. To model hydrodynamic behavior in CFB risers, three phase flows were assumed in the riser, the gas phase, the dispersed particle phase, and the clusters phase. The gas-solid multi-fluid model is extended to give the macroscopic averaged equations with constitutive equations for both particle phases from kinetic theory of granular flow. The clusters and the dispersed particles have their own fluctuating energy or two individual granular temperatures. Interactions between the cluster and its surrounding dispersed particles were obtained from kinetic theory of granular flow. Drag force for gas to dispersed particles and the clusters are empirically determined. The momentum exchange between dispersed particles and clusters is modeled using the concept of molecular dynamics. Cluster properties are predicted with the cluster-based approach. The distributions of volume fractions and velocities of gas, dispersed particles and clusters are predicted. Computed solid mass fluxes and volume fractions agree with Manyele et al. [S.V. Manyele, J.H. Parssinen, J.X. Zhu, Characterizing particle aggregates in a high-density and high-flux CFB riser, Chemical Engineering Journal, 88 (2002) 151-161.] and Knowlton [T.M. Knowlton, Modelling benchmark exercise. Workshop at the Eighth Engineering Foundation Conference on Fluidization, Tours, France, 1995.] experimental data.