浅谈石墨电极压型调速的方法及控制方式

石墨电极生坯生产的压型工序中压型调速方法的选择及其速度控制的稳定性直接影响着石墨电极的产量和质量。一般情况下，压型调速方法有两大类，一类是节流调速，另一类是容积调速，经研究表明，定量泵变频调速的容积调速方法是比较适宜的压型调速方法。     

热像仪替代热电偶测量气化炉壁温的探讨

描述常规铠缆式热电偶测量水煤浆气化炉壁温时存在的问题和原因,探讨利用红外热像仪代替热电偶测量炉壁温度的可行性,对热像仪测温方式的优点和其具体安装测温过程中可能存在的不利因素进行分析,提出相应的解决方法。     

A MODEL OF THE VISCOUS WALL REGION OF TURBULENT SHEAR FLOWS

The viscous wall region of a fully developed turbulent pipe flow is investigated using a nonlinear, time-dependent, three-dimensional model. In the model, the velocity field is assumed to satisfy periodic boundary conditions in the longitudinal and spanwise directions, the velocity vanishes at the pipe wall, the velocity fluctuations are assumed to vanish at large distances from the wall, and a law of the wall profile is imposed on the longitudinal and spanwise average of the longitudinal component of velocity outside the viscous wall region. The model equations are solved using pseudospectral methods and the computed mean velocity profile, fluctuation intensities, and turbulence production rate are found to be in good agreement with experiment in the viscous wall region. It is found that the bulk of turbulence production is generated by length scales larger than 40 in the spanwise direction and 200 in the longitudinal direction.     

低速球磨对多壁碳纳米管球磨特性的影响研究

利用低速球磨机对催化化学气相沉积法制备的多壁碳纳米管进行了球磨。透射电子显微镜实验结果表明。低速球磨机球磨可以使多壁碳纳米管开口和变短，球磨5h后碳纳米管开口和变短效果已经很明显；球磨20h后，发现碳纳米管变短到出现明显的团聚现象。X射线衍射实验结果表明，球磨20h后仍为多壁碳纳米管，每一层碳管仍为规则的石墨化结构。     

THE CONVECTIVE VELOCITY OF HEAVY PARTICLES IN TURBULENT AIR FLOWS

This paper examines the influence of the “crossing trajectories” effect on the convective velocity for heavy particles suspended in a turbulent air flow. The fluid energy spectrum “experienced” by a falling particle is deduced from experimental data and is used to evaluate the turbulent component of the convective velocity. The results indicate a significant increase in the rms value of the turbulent component due to the “crossing trajectories” effect.     

粗糙肋面上湍流热量传递中场协同关系的数值分析

用数值模拟的方法将湍流流动的传热分为传热层流底层和湍流层,来考察传热层流底层中温度梯度矢量与速度夹角对湍流流动换热的影响,用场协同理论分析了湍流条件下粗糙肋面的传热强化问题.     

PREDICTION OF A GAS-PARTICLE TURBULENT JET WITH THE FLUCTUATION-SPECTRUM-RANDOM-TRAJECTORY MODEL

A numerical treatment for determining the particle velocity and the trajectories in a two-phase flow is described herein and this new fluctuation-spectrum-random-trajectory (FSRT) model is proposed to account for the turbulent diffusion of particles. It is predicted for the flow of a turbulent axisymmetric gaseous jet laden with spherical solid particles of nonuniform size. The particle velocity and the concentration field are obtained by the revised volume average method. The predictions are compared with experiment.     

数据化计量控制提高电极加工质量

提出了数据化计量控制对提高电极加工质量的必要性，介绍了国产石墨电极专用环规的测量功能和使用方法，阐述了利用环规检测的数据调整控制电极加工参数的一些做法，说明通过数据化计量控制可明显提高电极加工精度和联接质量。     

液滴群速度场的激光粒子成像测速法

应用前向散射激光粒子成像测速法，测量了油滴群在水中的浮升速度。测试表明液滴群的浮升速度同单液滴有显著不同。应用片光束的侧向散射激光粒子成像测速法，测量了液滴群在流动液体中的速度分布，并观察到高浓度的速度扰动。     

AN EXPERIMENTAL AND NUMERICAL INVESTIGATION OF TURBULENT RECIRCULATING FLOW IN A CAVITY WITH AN INLET WALL JET

Recirculating turbulent flow within a cavity with an inlet wall jet was examined. In steady water flow profiles were constructed with measurements taken with a Laser Dopplcr Anemometer system mounted on a traversing mechanism for two different inlet velocities. The results are presented in terms of mean velocities and turbulent kinetic energy distributions. Comparisons are then made with results obtained using a finite difference computational scheme based on the k-ε turbulence model. In general, good agreement was obtained between the computer code predictions and the experimental data. However, the agreement between measurements and the code predictions was much better for the mean velocity field as compared to the turbulent kinetic energy field.     

VELOCITY MEASUREMENTS OF TURBULENT TWO-PHASE FLOW IN A HIGH-PRESSURE HOMOGENIZER MODEL

The effect of disperse phase volume fraction on the turbulence in a scale model of a high-pressure homogenizer was studied experimentally. Velocity fields of the continuous phase were measured using particle image velocimetry. Refractive index matching combined with digital filtering enabled measurement with disperse phase present. Geometry and physical properties were carefully scaled in order to ensure turbulent flow and disperse phase modulation comparable to that of a technical high-pressure homogenizer. The results show a widening of the jet downstream of the gap and increased Reynolds stresses in the region of high turbulence intensity. This is consistent with previous experiments under similar conditions. Furthermore, the spectra of turbulent kinetic energy were investigated, indicating that the increase in turbulent kinetic energy is mainly due to an increase in energy of eddies of large length scales.     

A METHOD FOR SEPERATING VELOCITY FLUCTUATION AND TEMPERATURE FLUCTUATION IN THE COURSE OF MEASURING TURBULENT PARAMETERS

A double hot-wire method is adopted to separate the mixed signal of temperature fluctuation and velocity fluctuation appearing in high temperature turbulences. The relationships among the various coefficients in the sensitivity equation for measuring turbulent fluctuations with constant temperature hot wire anemometer are deduced. Once these equations are being related to the temperature fluctuation sensitivity equation of a constant current hot wire anemometer, the temperature fluctuation signal may be taken out from the mixed signal, then the turbulent velocity fluctuation signal and other main turbulent parameters may be obtained.     

超细粉对石墨电极性能的影响

对加超细粉和不加超细粉的石墨电极试体进行了对比分析。结果表明,在配方干料中加入适量的超细粉能明显提高电极的机械强度,其抗折强度和抗压强度分别提高了９ ．７ ％ 和１０ ．６ ％ 。     

SIMULTANEOUS DEVELOPMENT OF VELOCITY AND TEMPERATURE PROFILES IN THE ENTRANCE REGION OF A PARALLEL PLATE CHANNEL: LAMINAR FLOW WITH UNIFORM WALL HEAT FLUX

Available boundary layer type solutions to the combined hydrodynamic and thermal entrance region problem are known to exhibit a discontinuity in the gradients of the velocity and temperature distributions in the entrance region. A new solution is presented which alleviates this shortcoming. The new solution is based on the hydrodynamic inlet-filled region concept originally proposed by Ishizawa (1966) and later adopted by Mohanty and Das (1982) to hydrodynamically developing flow in a channel. This concept is extended to the combined entry length problem by dividing the thermal entrance length into two lengthwise regions, a thermal inlet region and a thermally filled region. In the former, the effect of heat transfer between fluid and wall is confined within the thermal boundary layer developing along the wall. At the end of the thermal inlet region, the thermal boundary layers meet at the duct axis but the temperature profile is not yet developed. In the thermally filled region, the heat effects propagate throughout the entire cross section and the temperature profile undergoes adjustment in a fully thermal region to finally attain the fully developed form. A thermal shape factor is also introduced in the thermally filled region which ensures that all thermal quantities attain their fully developed values asymptotically. The new model is used to obtain solutions to the combined entry length problem for laminar flow through a parallel plate channel under the constant wall heat flux boundary condition. The analysis gives considerably better results for the local Nusselt number and thermal entrance length than previously available.     

粉煤水冷壁气化炉点火成功率探讨

介绍粉煤水冷壁气化炉在中试研发过程中点火系统出现的一些问题,初期点火成功率较低,从工艺、检测方式等方面进行改造后效果明显,点火成功率大大提高。     

导向管喷流床的最小喷动速度的研究

在内径９２ｍｍ的有机玻璃床内,使用四种没的物料,以空气作为喷动相流气体,综合考虑了床层的几何尺寸,以及气体和固体本身的物性,研究了导向管喷流床的最小喷动速度,得出了导向管喷流床的最小喷动速度的经验公式,以便对其设计和操作提供参考     

EFFECTS OF SURFACE TENSION ON LAMINAR FILMWISE CONDENSATION ON A HORIZONTAL PLATE IN A POROUS MEDIUM WITH SUCTION AT THE WALL

The problem of two-dimensional, steady-state film condensation on an isothermal finite-size horizontal plate embedded in a porous medium is studied for the case in which the plate faces upward into a region of dry saturated vapor. Due to surface tension effects, a two-phase zone is formed between the liquid film on the horizontal plate and the vapor zone. The effects of surface tension are shown to reduce the thickness of the liquid film and hence to increase the heat transfer performance of the horizontal plate. Furthermore, the results show that the dimensionless heat transfer coefficient depends on the Darcy number Da, the Jacob number Ja, the effective Rayleigh number Ra_e, the effective Prandtl number Pr_e, the wall suction parameter Sw, and the surface tension parameter Bo_c. When the surface tension effects are neglected and there is no suction at the wall, a closed-form correlation for the Nusselt number can be established.     

EFFECTS OF SURFACE TENSION ON LAMINAR FILMWISE CONDENSATION ON A HORIZONTAL PLATE IN A POROUS MEDIUM WITH SUCTION AT THE WALL

The problem of two-dimensional, steady-state film condensation on an isothermal finite-size horizontal plate embedded in a porous medium is studied for the case in which the plate faces upward into a region of dry saturated vapor. Due to surface tension effects, a two-phase zone is formed between the liquid film on the horizontal plate and the vapor zone. The effects of surface tension are shown to reduce the thickness of the liquid film and hence to increase the heat transfer performance of the horizontal plate. Furthermore, the results show that the dimensionless heat transfer coefficient depends on the Darcy number Da, the Jacob number Ja, the effective Rayleigh number Ra_e, the effective Prandtl number Pr_e, the wall suction parameter Sw, and the surface tension parameter Bo_c. When the surface tension effects are neglected and there is no suction at the wall, a closed-form correlation for the Nusselt number can be established.     

二次焙烧温度制度对电极焙烧结焦率的影响

为提高炭──石墨制品的质量，炭素生产采用一次浸渍和二次焙烧（或多次浸渍多次焙烧）生产工艺，隧道窑作为先进的二次焙烧技术具有焙烧温度低、周期短、能耗少等特点，是生产高质量电极重要的工艺技术装备，其焙烧温度制度是影响浸渍电极焙烧质量的关键因素．概述了浸渍坯料二次焙烧温度制度和沥青结焦率的关系。     

染料电极的光电转换效应研究

应用一种简便的旋转涂布方法,制备了卟啉/SnO_2,酞菁/SnO_2以及卟啉/酞菁/SnO_2单层和双层电极,在双层电极研究中发现,卟啉和酞菁层的涂布次序对形成的双层电极是否出现叠加现象有很大影响。对所出现的现象进行了初步的讨论。