锥形流量计下游支撑及取压位置的试验研究

锥形流量计应用广泛,其国际标准正在起草中。锥形流量计发展过程遇到两个问题：安全性和制造一致性差,具有双支撑结构的锥形流量计可解决此问题。为保证增加的双支撑结构不会影响锥形流量计的测量性能和较短的表体长度,需要研究下游支撑和下游取压位置。根据锥形流量计尾流流场的速度分布和压力分布的状况设计相关的改进试验,选择合适的下游支撑和下游取压位置。试验使用的锥形流量计经过特殊设计：锥体、下游支撑位置、下游取压位置都可以按照要求变换位置。试验得到适用于不同直径管道的下游取压位置和支撑位置的选取规律。不同管径和等效直径比下的锥形流量计试验数据显示：改进后的双支撑形式的锥形流量计样机比悬臂梁锥形流量计具有更好的流出系数不确定度。     

野外组合式软体油罐罐体材料燃烧特性研究

为了研究野外组合式软体油罐在不同辐射强度下的燃烧特性,通过锥形量热仪对软体油罐样本进行燃烧实验,选用25,35,50 kW/m2三种典型的热辐射强度进行研究,得到点燃时间、热释放速率、比消光面积、烟气生成速率、火焰形态等参数的变化规律.结果发现:热辐射强度为50 kW/m2时,点燃时间分别为25,35 kW/m2时的3...     

Double diffusion from a vertical truncated cone in a non-Newtonian fluid saturated porous medium with variable heat and mass fluxes

This paper studies the double diffusion flow over a vertical truncated cone with variable heat and mass fluxes in a porous medium saturated with non-Newtonian power-law fluids. A coordinate transformation is used to obtain the nonsimilar governing equations, and the transformed boundary layer equations are then solved by the cubic spline collocation method. Results for local surface temperature and concentration are presented as functions of power-law indexes, exponents for variable heat and mass fluxes, buoyancy ratios, and Lewis numbers. The local surface temperature and concentration of the truncated cone decrease as the exponents for variable heat and mass fluxes are increased. Moreover, a decrease in the power-law index of fluids tends to decrease the local surface temperature and concentration of the truncated cone.     

Soret and Dufour effects on heat and mass transfer by natural convection from a vertical truncated cone in a fluid-saturated porous medium with variable wall temperature and concentration

This work studies the Soret and Dufour effects on the natural convection heat and mass transfer near a vertical truncated cone with variable wall temperature and concentration in a fluid-saturated porous medium. A coordinate transform is used to obtain the nonsimilar governing equations, and the transformed boundary layer equations are solved by the cubic spline collocation method. Results for local Nusselt number and the local Sherwood number are presented as functions of Soret parameters, Dufour parameters, surface temperature and concentration exponents, buoyancy ratios, and Lewis numbers. Results show that increasing the Dufour parameter tends to decrease the local Nusselt number, while it tends to increase the local Sherwood number. An increase in the Soret number leads to an increase in the Nusselt number and a decrease in the Sherwood number from a vertical truncated cone in a fluid-saturated porous medium. The local Nusselt number and the local Sherwood number of the truncated cones with higher surface temperature and concentration exponents are higher than those with lower exponents.     

湿法磷酸装置中原料的闭路湿磨工艺

根据磨矿分级的原理,采用两段一闭路流程（粗磨-分级-细磨-浓密）,选用湿式棒磨机、湿式球磨机、斜窄流分级机和高效深锥浓密机,成功地运用于云天化国际化工三环分公司（原云南磷肥厂）磷矿磨矿系统,并运用此项技术的原理分别对四家公司以往的工艺进行改进,达到良好的磨矿分级效果。     

优化净化工艺确保高炉顶压稳定及TRT发电达产

介绍了湘钢新1#高炉煤气净化及TRT工艺,对造成高炉炉顶压力波动及TRT发电量低的原因进行分析,通过采取对净化控制系统的调整等系列措施达到稳定顶压、提高TRT发电量的作用。     

简析圆锥齿轮加工用走型板的设计

圆锥齿轮（俗称伞齿轮）的齿形加工一直是机械厂齿形加工的难点,我公司是利用走型板在伞齿刨床上来实现伞齿轮加工。这种加工方法是通过走走型板的齿形来完成伞齿轮的齿形加工,这样既提高了加工精度,又提高了效率,符合现代化生产的需求。通过现场的反馈,走型板设计和使用取得了良好的效果。     

高硬度铜渣综合利用研究

介绍了某种高硬度铜渣的性质,分析了用颚式破碎机和惯性圆锥破碎机两段开路将铜渣破碎到90%以上-8mm的方法,研究和解决了破碎过程中遇到的问题,简介了一段回收铜和铁的新选矿流程。     

Limit analysis of plates using the EFG method and second‐order cone programming

The meshless element‐free Galerkin (EFG) method is extended to allow computation of the limit load of plates. A kinematic formulation that involves approximating the displacement field using the moving least‐squares technique is developed. Only one displacement variable is required for each EFG node, ensuring that the total number of variables in the resulting optimization problem is kept to a minimum, with far fewer variables being required compared with finite element formulations using compatible elements. A stabilized conforming nodal integration scheme is extended to plastic plate bending problems. The evaluation of integrals at nodal points using curvature smoothing stabilization both keeps the size of the optimization problem small and also results in stable and accurate solutions. Difficulties imposing essential boundary conditions are overcome by enforcing displacements at the nodes directly. The formulation can be expressed as the problem of minimizing a sum of Euclidean norms subject to a set of equality constraints. This non‐smooth minimization problem can be transformed into a form suitable for solution using second‐order cone programming. The procedure is applied to several benchmark beam and plate problems and is found in practice to generate good upper‐bound solutions for benchmark problems. Copyright © 2009 John Wiley & Sons, Ltd.