CFD Simulation of Hydrodynamic Characteristics in Stirred Reactors Equipped with Standard Rushton or 45°-Upward PBT Impeller

The hydrodynamic characteristics generated by the standard Rushton or 45°-upward pitched-blade-turbine (PBT) impellers in a baffled reactor are numerically simulated for different off-bottom clearances (C = 1/3H and 1/2H) and agitator speeds (100, 150, 200, 250 and 300r·min-1) by using FLUENT code (Version 5.4). The results are compared with the experimental and simulated data in the published papers and good agreement is observed. The shapes of the profile of mean velocities seem independent to the speed of agitators under the experimental conditions (100-300r·min-1).     

Hydrodynamics Research on Amphibious Vehicle Systems： Modeling Theory

For completing the hydrodynamics software development and the engineering application research on the amphibious vehicle systems, hydrodynamic modeling theory of the amphibious vehicle systems is elaborated, which includes to build up the dynamic system model of amphibious vehicle motion on water, gun tracking-aiming-firing, bullet hit and armored check-target, gunner operating control, and the simulation computed model of time domain for random sea wave.     

Influence of top‐section design and draft‐tube height on the performance of airlift bioreactors containing water‐in‐oil microemulsion

The mixing and mass transfer characteristics of draft‐tube airlift bioreactors (DTAB) for a water‐in‐kerosene microemulsion, as a cold model of petroleum biodesulfurization, were studied. Incomplete gas disengagement at the top‐section of the DTAB and hence high gas recirculation were obtained with the microemulsion system for all the top‐section configurations employed in the present study especially at the high airflow rates. The ratio (S) of the volumes of the riser and the downcomer to the top‐section together with the gas disengagement abilities of the gas separator were both found to affect the mixing performance of the DTAB employed for the microemulsion system. Increase in the draft‐tube height resulted in significant increase in the mixing time (t_m) and a slight increase in the overall volumetric oxygen transfer coefficient (k_La). Increase in the diameter of the top‐section and the height of the liquid above the draft‐tube led to a decrease in k_La, the latter effect being less prominent. New correlations were developed that predicted the mixing time and oxygen transfer coefficients obtained in the present work with reasonable accuracy. Copyright © 2004 Society of Chemical Industry     

对鱼雷水动力学技术的再认识

通过对鱼雷水动力学技术发展的回顾,认定鱼雷水动力学技术现状已可满足常规鱼雷型号研制的需求,但又清醒地认识到其与世界水动力学技术发展的差距,据此根据新型鱼雷技术发展的需求和水动力学学科前沿技术发展的推动,提出鱼雷水动力学技术如何实现自主创新和跨越发展的原则和途径。     

Improvement of the Operating Processes in Boiler Furnaces of TÉTs-21 with the Help of Numerical Simulation of Thermal Gas Dynamic Processes

The use of numerical simulation and advanced means of computational hydrodynamics (domestic FlowVision software) for simulating the processes of flow and combustion in the systems for air and gas feeding, mixers, burners, and boiler furnaces has made it possible to advance the recirculation system and burners of the TÉTs-21 cogeneration plant and considerably reduce the NO_x emissions.     

流体力学在煤矿中的应用

叙述了流体力学在煤矿中的应用,阐述了流体力学的重要性。分析了流体力学在采掘机械中灭尘及液压系统、通风机械、选矿机械,尤其是在新型选矿机械中的应用。     

Evaluation of Diluted and Undiluted Trickle-Bed Hydrotreating Reactor with Different Catalyst Volume

In this work, a comparative study on the combined effects of hydrodynamics and kinetics on the hydrodesulfurization (HDS) of a straight-run gas oil (SRGO) using a trickle-bed reactor with and without diluent (SiC) and different catalyst volume (0.1, 0.07, and 0.050 × 10^-3 m³, respectively) was carried out. The tests were conducted in a pilot plant under conditions close to those used in industrial-scale units (5492 kPa, 445.4 m³(STP)/m³ H₂/oil ratio, 623-643K, 0.9 and 2.5 h^-1 LHSV values). The catalyst used was a commercial CoMoP/Al₂O₃ formulation shaped as tri-lobed extrudates (1/20 in, nominal size) or as crushed particles (d_p = 1.2 × 10^-3 m). Contrarily to that usually claimed, the undiluted systems showed better performance than those comprising small diluent (SiC) particles (d_p ~ 5 × 10^-5 m). Calculations to evaluate hydrodynamic variables (plug-flow behavior, wall effects, wetting, and back-mixing) were carried out in order to explain the observed facts. The possible influences of the size of the diluent particles used are discussed.     

消声滤波器栅板的流体动力学计算

本文对消声滤波器栅板的流体动力学计算问题．以级数周期解的形式及采用了保角映射方法．求得了流体的速度分布及作用在栅板上的阻力．并求得了通过栅板后流体压力降的表达式．为能量损失的计算提供了理论依据。     

Suspension codeposition in electrowinning cells: The role of hydrodynamics

Electrolytic codeposition of particles suspended in a plating bath constitutes a novel method for producing certain alloys. The suitability of this approach for the manufacture of copper-phosphorus alloy from a suspension of red phosphorus in acid copper sulphate solution was assessed in a scaled, full-depth, transparent electrowinning cell operated continuously. The suspension was maintained both by the jetting of recirculated electrolyte and by the natural flows of electrolyte and anodic bubbles. Smooth thick deposits of copper containing acceptably uniform, optimal levels of phosphorus were produced. The vertical variation of phosphorus in the cathode is explained by a detailed consideration of hydrodynamic flow near the cathode.