搅拌槽内的总体泵送能力系数

通过激光多谱勒测速仪对搅拌槽内三维流场的测量，定义了具有三维意义上的总体泵送能力系数，并提出了由切向速度定义的泵送能力系数的概念，这些量较初始泵送能力系数和循环流量更能真正反映搅拌槽内的流动和混合。     

CFD simulation of flow and mixing characteristics in a stirred tank agitated by improved disc turbines

To reduce the power consumption and improve the mixing performance in stirred tanks, two improved disc turbines namely swept-back parabolic disc turbine (SPDT) and staggered fan-shaped parabolic disc turbine (SFPDT) are developed. After validation of computational fluid dynamics (CFD) model with experimental results, CFD simulations are carried out to study the flow pattern, mean velocity, power consumption, pumping capacity and mixing efficiency of the improved and traditional impellers in a dished-bottom tank under turbulent flow conditions. The results indicate that compared with the commonly used parabolic disc turbine (PDT), the power number of proposed SPDT and SFPDT impellers is reduced by 43% and 12%, and the pumping efficiency is increased by 68% and 13%, respectively. Furthermore, under the same power consumption (0-700 W·m^-3), the mixing performance of both SPDT and SFPDT is also superior to that of Rushton turbine and PDT.     

Heat transfer and pressure drop performance of alumina–water nanofluid in a flat vertical tube of a radiator

This work presents experimental investigation on the effects of nanofluid inlet temperature (40–90°C), Reynolds number (12,000–30,000), particle concentration (0–1 vol.%), and air velocity (0.25–0.55?m/s) on thermal and flow characteristics of water-based alumina nanofluids in a flat vertical tube of a radiator. The specific heat capacity, viscosity, density, and thermal conductivity were measured experimentally. The heat transfer coefficient enhanced (up to 31%) with an increase in fluid inlet temperature, particle volume concentration, Reynolds number as well as air inlet velocity. The pressure drop increased with an increase in the particle volume concentration and Reynolds number, while it decreased slightly with an increase in the fluid inlet temperature. The friction factor and pumping power increased with particle concentration. The friction factor decreased, while the pumping power increased with sn increase in fluid flow rate.     

Power draw of a high‐Shear homogenizer

The power draw of a high‐shear rotor‐stator homogenizer has been characterized in laminar, transitional, and turbulent operation. The power draw is comprised of two components — that associated with mixing and that associated with a bushing and bearings in the device. In turbulent operation, the mixing power draw is influenced primarily by pumping mode (up‐ or down‐pumping), and to a lesser extent, by vessel baffling and other geometric parameters. Mixing power draw can be characterized in terms of power number across the Reynolds number spectrum if an empirical Froude number correction is applied.     

游梁式抽油机节能技术综述

在采油成本中,抽油机电费占30%左右,年耗电量的20%~30%,为油田电耗的第二位,仅次于水。游梁抽油机的抽油系统的总效率在国内一般地区平均只有12%~23%,先进地区至今也不到30%,由此可见降低抽油系统高能耗的迫切程度与难度。游梁式抽油机效率低、能耗高的主要原因是动力机与工作机不匹配。为了使之匹配,提高抽油机的效率,抽油机主要通过结构的改进和抽油机节能电控装置两个方面来达到节能的目的。本文从结构的改进和抽油机节能电控装置两个方面归纳了抽油机的节能技术。     

新型上游泵送机械密封的性能研究

针对内径开槽的螺旋槽型上游泵送机械密封易于吸入固体颗粒而产生磨粒磨损的缺陷 ,研制开发出具有内外双密封坝的新型上游泵送机械密封端面结构。实验研究结果表明 ,新研制的双密封坝型上游泵送机械密封在密封性能、摩擦性能等方面明显优于普通的接触式机械密封 ,且与内径开槽上游泵送机械密封相比 ,其防固体颗粒能力大大提高。     

机械抽真空系统在减压蒸馏装置中的应用

在过去与现代的减压蒸馏装置中,具备一、二、三级抽空器的蒸汽抽真空系统始终占据着主导地位。而近年,一种新型的抽真空系统——机械抽真空系统正在慢慢地改变传统的抽真空方式。相对于传统的蒸汽抽真空系统,它的出现和逐步应用将会引领一场减压蒸馏中划时代的变革,通过对这两种抽真空方法的比较,浅析两种方法在减压蒸馏装置中的应用情况。     

Using CFD and Ultrasonic velocimetry to Study the Mixing of Pseudoplastic Fluids with a Helical Ribbon Impeller

A commercial CFD package was used to simulate the 3D flow field generated in a cylindrical tank by a helical ribbon impeller. The study was carried out using a pseudoplastic fluid with yield stress in the laminar mixing region. Ultrasonic Doppler velocimetry (UDV), a noninvasive fluid flow measurement technique for opaque systems, was used to measure xanthan gum velocity. From flow field calculations and tracer homogenization simulations, power consumption and mixing time results were obtained. The torque and power characteristics remain the same for upward and downward pumping of the impeller, but the mixing times are considerably longer for the downward pumping mode. Overall, the numerical results showed good agreement with experimental results and correlations developed by other researchers. From the power and mixing time results, two efficiency criteria were utilized to determine the best pumping mode of the impeller.     

方箱泵吸式混合澄清器泵吸力的研究

本文从理论上分析了混合澄清器泵吸力的成因和影响泵吸力的诸因素,利用圆形射流模型导出了二参数的泵吸力方程.在方箱泵吸式混合澄清器中,用六叶平桨和六叶闭式叶轮以水-有机相(磺化煤油+5%正丁醇)和碱性铝液-有机相为实验体系,测定了搅拌转速、搅拌器的安装高度、混合物相比及流体流量对泵吸力的关系.由这些实验数据求得泵吸力方程的参数.该模型与实验数据吻合较好.     

Mixing analysis in a coaxial mixer

The performance of a coaxial mixer in the laminar-transitional flow regime was numerically investigated with Newtonian and non-Newtonian fluids. These mixers comprised two shafts: a central fast speed shaft mounted with an open turbine, and a slow speed shaft fitted with a wall scraping anchor arm. To model the complex hydrodynamics inside the vessel, the virtual finite element method (POLY3D^TM software) coupled with a Lagrange multiplier approach to cope with the non-linearity coming from the rheological model was employed. Co-rotation and counter-rotation mode were compared, based on several numerical criteria, namely, mixing time, power consumption and pumping rate. It was found that co-rotating mode is more efficient than counter-rotating mode in terms of energy, pumping rate and homogenization time.     

R134a/R23-DMF溶液气泡泵输送性能实验

搭建了气泡泵输送性能实验装置,对提升管管径为6、8、12 mm的气泡泵输送不同R134a/R23-DMF浓度溶液的性能进行实验研究。结果表明,在相同制冷剂浓度情况下,三种管径气泡泵的气相流量随着输入功率的增加均呈线性增加趋势,液气比随着气相流量的增加均呈现反向趋势,发生温度随着输入功率增加而线性升高,而输入功率对于系统压力的影响较小。在不同制冷剂浓度情况下,R134a/R23浓度对液气比的影响不明显,但对系统压力影响很大,R134a/R23浓度的增加使得发生温度有微小的升高。8 mm管径气泡泵液气比和稀溶液流量变化幅度居中,而气相流量变化范围最宽,发生温度最低,比较适合用于扩散吸收制冷系统。这些实验结果对扩散吸收制冷系统的气泡泵设计具有重要参考价值。     

双层桨自吸式气-液分散搅拌槽的单相流模拟

运用计算流体动力学(CFD)方法对双层桨自吸式气液分-散搅拌槽进行单相流数值模拟。考察了不同气体分散通道叶片角度、不同下层桨类型、不同桨叶间距对搅拌槽内宏观流动场的影响。研究发现:气体分散通道叶片角度为30°时,流体在上层桨所在平面处的流动没有出现较大的扭曲流动,漩涡较小,能量损耗较少。下层桨为六叶上斜叶桨时,下层桨具有较强的泵送能力,能够将液体有效的泵送到上层桨周围。桨叶间距增大,使槽内轴向循环流动范围增大,但是有可能造成下层桨泵送能力的降低。     

Preparation and Photoproperties of a Transparent Alumina Film Doped with Energy-Transfer-Type Laser Dye Pair

Doping of an energy-transfer-type laser dye pair into an alumina film was tried in order to increase the efficiency of its photoproperties. A transparent alumina film was prepared from an aqeous sol solution by the sol—gel process. Changes in the fluorescence of the pyranine were monitored during the process from aqueous sol solution to the dried gel. The undesirable dye aggregation usually observed in aqueous solution was largely reduced in the film. The laser emission of rhodamine B by N₂ laser pumping can be increased by the addition of rhodamine 6G, which enhances pumping efficiency. It indicates that this doped film operates as a compact dye laser film.     

搅拌釜中泵送能力系数的研究

简要分析了圆盘涡轮搅拌釜中泵送能力系数的研究情况及存在的问题。通过激光多谱勒测速仪对搅拌釜内三维速度的测量。定义了三维意义上的总体泵送能力系数，并提出了由切向速度定义的切向泵送能力系数的概念。总体泵送能力系数较初始泵送能力系数和循环充量更能真实反映搅拌釜内的流动。叶安装刘度为搅拌釜直径的１／３时，轴向或径向总体泵送能力系数约为１．９；叶轮安装高度为搅拌釜直径的１／２时，轴向戏向总体泵送能力系数的为     

PET缩聚过程脱挥方式比较——抽真空及通氮气

抽真空及通氮气是 Ｐ Ｅ Ｔ缩聚过程脱除小分子的两种方式， Ｐ Ｅ Ｔ 间歇缩聚实验研究表明：通氮气脱挥时聚合度一直上升，而抽真空脱挥时聚合度趋向某定值；脱挥速度与通氮位置有关；通氮气脱挥得到的聚合物比抽真空脱挥得到的色泽白。     

Oxidation of methane over platinum in a solid proton-conducting electrolyte cell

Studies of the complete oxidation of methane on a Pt electrode-catalyst in the cell with a solid proton-conducting electrolyte (CH₄ + O₂, Pt ¦ SrCe_0.92Dy_0.08O₃ ¦ Pt, H₂O + N₂) were carried out. The non-Faradaic effect of electrochemical hydrogen pumping on the rate of methane oxidation has been demonstrated. The induced change in the reaction rate at anodic polarization of a Pt electrode-catalyst was over two orders of magnitude higher than the rate of hydrogen pumping from the reaction zone through the electrolyte.     

多泥砂地区城市污水泵站的除砂设计

介绍了青岛昌乐路泵站和厦门第二污水处理厂厂外泵站的除砂设计,对两种除砂方式进行了分析和比较,并提出了两种除砂方式的适用场合。     

高黏度齿轮泵径向力的消除

将谐波齿轮传动原理引入齿轮泵领域,提出了一种高黏度齿轮泵,分析了高黏度齿轮泵的结构及其径向力平衡的原理,对高黏度齿轮泵的径向液压力进行了分析。结果表明,高黏度齿轮泵有效地消除了齿轮泵的径向力,在下游阻力增加时,不会出现随着泵压力的增加而出现径向力变大的现象,高黏度齿轮泵的两个高压腔在一个转动周期内完成两次排料,提高了泵的输送效率和压力稳定性。     

相变对螺旋槽液膜密封性能的影响

为了探究液膜相变现象对螺旋槽液膜密封性能的影响。基于质量守恒定律,以赫兹方程推导质量源项并建立非接触式液膜密封相变模型。使用有限体积法对控制方程进行离散,分析了液膜相变现象对非接触式机械密封性能的影响。结果表明：相变现象对密封性能的影响与密封功用密切相关,且动压槽开槽位置及槽内相态分布对密封性能与端面压力分布影响显著;液膜发生相变后,下游泵送型密封开启力增大且泄漏量减小;上游泵送型内槽式密封开启力先增大后减小,泄漏量先减小后增大再减小,外槽式密封开启力呈线性增大,泄漏量先减小后增大;相变发生在槽区时,会导致动压效应明显减弱,对端面压力分布影响较大。     

上游泵送机械密封的基本原理分析

上游泵送机械密封是利用低压流体实现对高压流体密封的一项新的密封技术,它的典型特征是在一密封端面开有起上游泵送作用的浅槽,利用流体动压效应使得两完整的流体膜分开,这极大地改善了密封端面的润滑状态。本文介绍了分析了该类机械密封的基本原理。