混铁炉综合炉衬技术开发及应用

文中论述了混铁炉采用综合炉衬技术并通过实际应用有效地延长了混铁炉的寿命。炼钢厂混铁炉内衬采用综合炉衬技术，是钢铁厂降本增效的有效措施。     

混频器设计中的关键技术研究

混频器已经在诸多领域中得到了广泛的应用,其技术指标的好坏直接影响到整机性能的发挥。从混频器的基本概念出发,分析了混频器设计中的关键技术,如噪声系数、变频损耗、动态范围、隔离度、混频失真等对接收机性能的影响,并从工程角度出发,指出在工程设计中应注意的要点。本文所得结论在工程应用中得到了验证。     

SMX型静态混合器传热特性实验研究

实验测量3种不同组合形式的SMX型静态混合器的传热特性参数,并采用Moffat提出的误差传递理论分析了实验数据的真实性。结果表明,在3200≤Re≤6000范围内,3组不同组合形式的SMX型静态混合器的摩擦因子、努赛尔数均与雷诺数呈对数线性关系,且4板片的斜率大于3板片及2板片;对湍流换热强化作用比较,4板片形式的更为显著,传热效率相较于2板片形式的静态混合器提高约39%,而3板片SMX型静态混合器的传热效率比2板片SMX型静态混合器稍高。     

大型双转子连续混炼机转子混炼段混合性能的研究

对?450大型双转子连续混炼机转子混炼段混合性能和力学性能进行研究。分析啮合间隙、转子导程、转子正反段长度比等几何参数对混炼机剪切应力分布、转子所承受的轴向力和扭矩的影响。研究表明,转子啮合间隙对转子混合性能和力学性能影响最为显著,随着啮合间隙的增大,剪切应力、转子所受的轴向力和扭矩会逐渐下降;转子导程变化对转子力学性能的影响相对明显;转子正反段长度比不仅影响转子所承受的轴向力,而且还影响剪切应力分布,对转子所受扭矩影响不大。     

Development and characterization of micro-dispersed lacquer

本文利用一种特制的搅拌装置来制备微分散生漆。研究了在不同的搅拌速率和搅拌时间下所获得的生漆微粒子的直径和性能的关系。粒度分布测定表明,经过60分钟且每分钟240转搅拌处理的生漆,其粒子直径分布最窄,平均为0.194微米。凝胶色谱(GPC)分析显示生漆中的寡聚体增加的同时单体的百分含量减少了,意味着在搅拌的过程中发生了聚合反应。另外,微分散生漆的粘度、干燥成膜时间、膜亮度、膜颜色、膜光泽以及耐紫外线等特性也作了深入的探讨。     

Scale-up of pump-mix mixers using CFD

Effect of scale on the drop size distribution in a pump-mix mixer has been studied. A network of zones model was developed to predict the drop size distribution at different locations in the mixer. Computational fluid dynamics model was used to obtain the flow patterns in the mixer and to identify zones based on the flow patterns. Population balance equation was solved for all the zones of the mixer. The model was validated with the experimental data over a wide range of parameters as well experimental data from the published literature. The model was further extended for scale-up studies. Two different scale-up criteria were studied. It was observed that equal power consumption per unit mass and geometrical similarity is a better scale-up criterion as compared with equal tip speed criterion for pump-mix mixers.     

Computational-fluid-dynamics study of a Kenics static mixer as a heat exchanger for supercritical carbon dioxide

The thermal efficiency of a Kenics^® KM static mixer used to pre-heat supercritical carbon dioxide, under high pressure conditions, is studied using computational fluid dynamics (CFD). A mesh sensitivity analysis is performed and the CFD model is validated against experimental results on heat transfer with conventional and supercritical fluids. Three turbulent models - standard k-?, RNG k-?, and k-ω - are employed to model the flow and heat transfer under high pressure conditions; the effects of large variations of the physical properties in the pseudo-critical region of the fluid are also studied. The RNG k-? model gives results that are closer to the experimental data than the other two turbulence models. The numerical results show that the static mixer has a thermal efficiency more than three times higher than that of a conventional empty pipe heat exchanger with similar heat transfer area.     

PGSS-drying: Mechanisms and modeling

Micronization of polyethylene glycol from aqueous solutions has been successfully performed with particles from gas-saturated solutions (PGSS)-drying process, producing spherical PEG particles with average particle size of 10 μm and residual water content below 1 wt%. Based on experimental results, an analysis of the fundamentals of the process has been developed, discussing mass and energy balances, phase equilibrium conditions, mass transfer rates and atomization mechanisms. Some discrepancies between experimentally observed moisture concentration in powder and calculations based on the mass balance and the phase equilibrium have been observed, which have been attributed to the kinetic evolution of pressure and temperature along the expansion path. The static mixer used to saturate the solution with CO₂ has been analyzed with phase equilibrium and mass transfer calculations, concluding that a significant fraction of water is extracted to the gas phase already in the static mixer, and high CO₂ concentrations are achieved in the liquid due to the high solubility of CO₂ in PEG. All experimental trends of variation of particle size with process parameters can be explained considering a flash-boiling atomization mechanism dependant on the concentration of CO₂ in the solution after the static mixer.     

一种U 波段鳍线单平衡混频器的设计

本文介绍了一种U 波段鳍线单平衡混频器的设计过程并给出了测试结果。混频器使用M/A-COM 公司的肖特基势垒二极管MA4E2037,整个电路制作在一块厚度为0.127mm 的RT-Duroid 5880 软基片上。射频端口采用鳍线过渡,本振端口通过波导-微带探针过渡,中频通过SMA 接头输出。测试结果显示,鳍线悬置微带线结构的混频器在本振为42 GHz, 射频在40～60GHz 范围内变化时,其变频损耗小于8.71 dB,本振到射频的隔离度大于25dB。