不同喷吹方式对鱼雷罐脱硫动力学条件影响水模试验研究

通过水力学模型试验,分析了不同喷吹方式下鱼雷罐熔池内的流动状态,研究了不同喷吹方式下鱼雷罐喷吹脱硫动力学条件的差异以及工艺参数对熔池混匀时间的影响规律。结果表明：喷吹方式对鱼雷罐脱硫动力学条件影响较大;试验条件下,相同工况不同喷吹方式下熔池混匀时间相差幅度达37%;不同插入深度下,三种喷吹方式对熔池动力学条件的影响规律不尽相同;研究开发新型喷吹方式,避免喷吹气泡上浮过程中的冲撞融合与缩短喷口至两端死区距离,可以降低熔池混匀时间,改善鱼雷罐喷吹脱硫动力学条件。     

复合喷吹铁水脱硫喷吹系统稳定性研究

结合国内某钢厂120 t复合喷吹脱硫改造项目,对复合喷吹铁水脱硫喷吹系统的稳定性进行了研究。根据现场调试及生产数据,对喷吹罐压力控制方式、粉末流量调节阀控制逻辑、喷吹罐下流化气体流量、助吹气体流量对喷吹稳定性产生影响的因素进行了研究。研究表明,喷吹罐采用恒压控制可以实现喷吹罐与喷吹管道间压差的稳定控制,有利于喷吹速度的稳定控制;粉末流量调节阀采用实时动态调整控制逻辑,能有效提高喷吹速度控制的精度;粉气比控制在32左右,喷吹过程连续稳定,管道及喷枪无堵塞现象,铁水喷溅小。     

底吹布置模式对100t转炉熔池动力学条件的冷态研究

为了探究不同底吹布置模式对熔池的搅拌效果,以某钢厂100 t转炉为研究对象,通过冷态水模拟研究不同底吹布置方式以及不同底吹气体流量对熔池混匀时间的影响。研究表明,四孔矩形底吹布置时,底吹流股对熔池的搅拌更充分,死区面积小,混匀时间最短。熔池混匀时间随着底吹气体流量的不断增大,存在先减小后增大的规律。     

130 t电弧炉熔池吹氧搅拌工艺优化模拟

为有效提高电弧炉熔池液体流动,以130 t电弧炉为模型,基于相似理论,进行了1∶4.35的水模拟试验,研究不同喷吹强度、氧枪角度及氧枪排布方式对电弧炉熔池混匀行为的影响,优化了设计方案。研究结果表明,影响熔池混匀时间的因素主要有氧枪喷吹流量和排布方式,氧枪角度对熔池混匀效果的影响较小。随着氧枪流量的增加,熔池所需混匀时间逐渐减少,当喷吹流量为21 m³/h(标准)和24 m³/h(标准)时,熔池混匀时间比喷吹流量为15 m³/h(标准)分别减少了14%和19.6%;氧枪对熔池的搅拌效果会随着氧枪排布方式的不同而改变,当氧枪排布方式为C时,液体流动可形成大循环,熔池内无死区,熔池混匀状态最好,排布方式D次之,当排布方式为A和B时,由于氧枪数量的减少,对熔池起不到良好的搅拌效果。     

150t提钒转炉底吹元件布置物理模拟研究

通过水力学模拟实验,在1∶6的物理模型上,对承钢150t提钒转炉的底吹元件布置进行优化,运用测电导率法测定了7种不同底吹元件布置方案转炉熔池的混匀时间.实验结果表明:方案3熔池混匀时间最短,为最佳底吹元件布置方案；在本试验条件下,枪位在225 mm,顶吹气体流量为81～83.3 m3/h.,底吹气体流量为1.8 m3/...     

45t电弧炉埋入式氧枪水模拟研究

通过在电弧炉侧壁加入侧吹氧枪向钢液中喷吹氧气,提高熔池搅拌力。对上述模型进行水模拟实验,观察侧吹枪射流形状及熔池内液体的流场,记录钢液的混匀时间,从而确定了最佳的喷吹水平角、侧枪垂直高度,侧枪垂直角,以及侧枪布置位置。     

电弧炉炼钢出钢过程在线喷粉水模拟优化研究

通过水模拟实验研究不同试验方案下的熔池混匀时间,分析喷枪角度、喷枪枪位、喷枪流量对出钢过程中钢包熔池搅拌效果,确定最佳的喷吹工艺参数,为现场生产提供理论指导。     

电弧炉埋入式喷吹熔池搅拌水模拟优化研究

通过水模拟实验研究不同实验方案下熔池混匀时间及流场分布情况,重点探究了两支埋入式喷枪在不同喷吹流量、布置方式、垂直角大小、垂直高度时对电弧炉熔池的搅拌效果,从而确定出最佳的埋入式喷枪安装方式,为现场生产提供了理论指导。     

65t电弧炉复合吹炼的水模拟研究

本文在相似原理的基础上利用1:4的水力学模型对某钢厂65t电弧炉各吹炼参数进行模拟研究,重点研究不同侧吹、底吹流量以及不同底吹位置布置方案对熔池搅拌效果的影响。在此基础上,分别研究底吹流量、侧吹流量和底吹位置布置对熔池混匀时间的影响。实验结果表明,侧吹、底吹流量对熔池混匀时间均有显著影响,侧吹流量较底吹流量影响更显著,底吹位置分布对熔池混匀时间影响较小。工业试验结果表明,与无底吹条件相比,复合吹炼能更好的搅拌熔池,提高脱碳速率,降低钢铁料消耗。     

120t铁水复合喷吹脱硫工艺设计及应用

通过对喷吹管路和L1控制系统的优化,以及对粉末调节阀和喷吹罐底部流化装置的优化设计,使得该铁水复合喷吹脱硫系统在某厂的实际应用中取得了良好的效果,各项性能指标均达到了设计的预期目标。     

150t提钒转炉模型中炉壁冲刷现象的研究

通过6:1水力学模型,对150t提钒转炉中的炉壁冲刷现象进行研究.试验中,使用电导率仪连接压力探头直接测试在纯顶吹、顶底复吹和顶底复吹增加侧枪三种状况下的炉壁上的压力变化.试验结果表明,氧枪喷孔之间的炉壁受到的压力更大,相对的区域受到的压力相对较小;底枪集中布置能降低顶吹气流对相应区域炉壁的冲刷,但底吹气流量不宜过大;...     

Investigation of two‐phase flow mixing between two subchannels

The cross flow between subchannels in a BWR fuel assembly has been typically analyzed using three types of mixing models, namely, pressure difference, turbulent mixing, and void drift which are expressed by time‐averaged flow parameters. However, in our previous paper, we expressed the above cross flow phenomenon simply by a fluctuating pressure model and confirmed its validity experimentally. In this present study, we examine the relationship between the fluctuating pressure difference and the cross flow rate more precisely by using a short mixing zone with no steady pressure difference. Results show that the experimental cross flow data agree well with the calculations using this model. Furthermore, we tried to express the fluctuating pressure difference by using a sinusoidal wave as a new cross flow model. This model is shown to have no dependence on frequency. We verify that the cross flow can be analyzed using only the pressure difference amplitude. © 2000 Scripta Technica, Heat Trans Asian Res, 29(5): 412–426, 2000     

Experimental and numerical study of thermal stratification in a mantle tank of a solar domestic hot water system

The simulation and the optimisation of the mantle tank of solar domestic hot water systems needs dynamic simulation over long periods of time (e.g. 1 year). A model for such a mantle tank was developed by using the zonal approach. The dimensions of the zones are determined based on physical considerations. A mixing coefficient is identified to model the water flow in the mantle heat exchanger. Comparisons of the results of temperatures distribution of the model and of experiments show a difference <7% for three positions of the inlet water flow in the mantle heat exchanger.     

高压气体引射器的试验研究和仿真

以一个高压气体引射器试验台为基础，开展了一系列高压引射试验，研究高背压条件下引射器的工作特性。同时，利用计算流体力学方法对引射器引射，混合过程进行了详细的研究。系列试验表明引射系数对引射气流的压力变化不敏感，但高背压的确对引射气流和被引射气流在混合管内的混合，扩散和流动产生影响。数值仿真克服了试验设备的限制，并显示了引射流动的详细情况。数值仿真结果表明：在一定的工况下，总存在一个最佳面积比和最佳相对位置以对应最大引射系数(即使引射器达到最大工作效率)，而其物理表现为引射器喉管壁面压力最低。正是它们之间的内在关系决定了气体引射器的工作特性。     

Numerical investigation on mixing behavior of fuels inreacting and non-reacting flow condition of a cavity-strut based scramjet combustor

The present study discusses the effects of reacting and non-reacting flow conditions on the flow physics of a scramjet combustor. A cavity based supersonic combustor with a triangular strut is used to analyze the mixing behavior of fuels namely, hydrogen and ethylene, numerically. In this context, the influence of Mach number on static pressure distribution, mixing efficiency and the mole fraction of hydrogen and ethylene is analyzed. Our study reveals that there is a strong interplay between flow conditions viz., reacting and non-reacting and Mach number on flow field characteristics. It has been observed that the ignition delay time is very less for hydrogen fuel as compared to ethylene fuel. Further, the mixing efficiency is found to be maximum at Mach 2.5 and Mach 3.5 for hydrogen and ethylene, respectively for reacting flow conditions. Moreover, it was observed that additional igniters are required to enhance the rate of mixing in case of ethylene since the complete mixing of ethylene and air occurs at higher Mach number. It is seen that the deviation in the static pressure and mixing efficiency for reacting and non-reacting flow increases with the increase in Mach number. Further, this deviation is found relatively higher for hydrogen as compared to ethylene.     

Enhancement of Interphase Transport in Mini-/Microscale Applications Using Passive Mixing

Structured mini-/microscale reactors continue to receive attention from both industry and academia due to their low pressure drop, high heat and mass transfer rates, and ease of scale-up relative to conventional reactor technology. Commonly considered for reactions such as hydrogenations, hydrodesulfurization, oxidations, and Fischer–Tropsch synthesis, the performance of these systems is highly dependent on mixing and the interfacial area between phases. While existing literature describes the initial flow patterns generated by a broad range of two-phase contactors, few studies explore the dynamic impacts of downstream passive mixing elements. Experimental and computational methodologies for characterizing two-phase flow pattern transitions, pressure drop, and heat and mass transfer are discussed, with relevant examples for serpentine and Venturi-based passive mixing designs. The efficacies of these two configurations are explored in the context of pressure drop, conditions leading to significant interface renewal, and design considerations for optimizing mass transfer. Challenges associate with the characterization of multiphase flow through these systems are highlighted, and strategies suggested for both experimental and computational analysis of dynamic flow patterns and fluid–fluid interactions.     

NUMERICAL SIMULATION OF GAS FLOW AND MIXING IN A MICROCHANNEL USING THE DIRECT SIMULATION MONTE CARLO METHOD

The direct simulation Monte Carlo (DSMC) method was employed to investigate gas flow and mixing in a microchannel at near-atmospheric pressure conditions. Simulations for pressure-driven flows were first carried out for a single-component gas flow in a microchannel. Mixing of two parallel gas streams (H 2 and O 2 ), separated by a splitter plate and then entering a microchannel, was considered. The effects of the inlet velocities, the inlet-outlet pressure difference, and the pressure ratio of the incoming streams (H 2 and O 2 ) on the mixing behavior were considered. The effect of the "accommodation coefficient" of the solid wall of the microchannel on the mixing behavior was also examined. The simulation results indicate that mixing decreases with the increase of inlet-outlet pressure difference. When the two streams enter the microchannel with different inlet pressures, mixing is found to decrease with the increase of the pressure ratio. The mixing process is found to be much slower for nearly specularly reflected walls compared to the mixing in a microchannel with completely diffuse walls.     

硫化亚铁自然氧化倾向性的研究

含硫油品储罐中，由于硫腐蚀形成的主要硫化产物硫化亚铁的氧化放热是引起油品自燃的主要原因，对硫化亚铁的自然氧化进行了跟踪实验，考查了硫化亚铁自然氧化的温度变化特征，绘制了不同条件下硫化亚铁的氧化升温曲线，分析了水分、油品及空气流量对氧化升温特征的影响，为实际生产提供了有利的理论依据。     

A Thermally Stratified Solar Water Storage Tank

Thermal stratification and fluid motion in solar water storage tanks have been investigated theoretically and experimentally. Transparent glass test sections were used in the experiment to permit visual observation of the flow fields. An electric water heater was used to simulate solar collectors. Experiments were conducted under different conditions in which a solar system is likely to operate. Altogether, about 130 test runs were conducted at various temperatures and flow rates of water at the inlet to the store. It was found that the location of the inlet/outlet ports has considerable effect on the mixing of incoming fluids with those in store

Equations have been developed to predict temperature distribution in the store. Time dependent boundary conditions, which use finite mixing zone concepts, have been used to solve the equation. The predicted temperature distribution within the store shows good agreement with the experimental results.