水平松料器布置方式对流场结构的影响

本文就水平松料器的尺寸，布置间距，布置高度对烧结料层中气体流场结构的影响进行了冷态试验研究；确定了松料器的垂直影响范围，展示了尺寸，布置高度，布置间距三者对流场结构的显著影响，认为，只有综合考虑三者的影响才能最大限度地发挥水平松料器改善气流分布，增产，节能的作用。     

等压烧结技术的实验研究与机理探讨

在实验室条件下研究了通过孔隙调控设备－－水平松料器调控烧结料层内部结构的等压烧结技术及其料层中气体流场和势场分布状况。在此基础上，利用流体力学的基本原理，揭示了等压烧结技术和实现等压烧结的气体机理。     

水平松料器对烧结料层中气流分布的影响

本文通过实验室冷态实验研究，分析了水平松料器对烧结料层中气流分布的影响。试验结果表明，水平松料器在横向（水平）４倍于其尺寸左右的有效范围内改变了料层中的气流分布，气流速度增大。这有助于水平松料器的合理布置与应用。     

罩式炉内保护气体流场测试与分析

通过对罩式炉内保护气体的流动静压和动动压的测量，计算出了炉内保护气体的流场分布，分析了引起罩式炉内保护气体流态不稳定、流场分布不均匀的原因，提出了改善炉内保护气体流动状态和流场分布的具体措施，为改善冷轧钢卷罩式炉退火质量提供参考。     

松料器作用的机理探讨

文章通过试验研究,实测了松料器的作用,详细分析了松料器作用的机理,并认为松料器是增产节能的简易而有效的措施,值得推广。     

罩式炉内保护气体流场测试与分析

通过对罩式炉内保护气体的流动静压和动压的测量,计算出了炉内保护气体的流场分布,分析了引起罩式炉内保护气体流态不稳定、流场分布不均匀的原因,提出了改善炉内保护气体流动状态和流场分布的具体措施,为改善冷轧钢卷罩式炉退火质量提供参考.     

工业电除尘器内部电流体场的数值解法

本文基于有限差分法，针对工业电除尘器的工作过程，根据泊松方程和紊流流场双方程模型建模，得到了非均匀场强作用下的流场分布和包括紊流脉动粘性的紊流流场作用下的电场分布，对于优化设计和完善电除尘器的收集理论具有重大意义，为电除尘器在现场的应用提供理论依据和技术支持。     

电极感应熔化气体雾化制粉工艺气体流场模拟研究北大核心

采用计算流体动力学FLUENT软件模拟研究了电极感应熔化气体雾化制粉工艺的气体流场状态,分析了雾化气体压力、气体温度以及熔化室与雾化室气体压力差对气体流场特征的影响规律。结果表明,不同工艺参数下,气体流场均为一系列膨胀波和压缩波形成的“项链状”射流结构;提高气体压力和温度能有效提高气体射流速度,理论上有利于熔体破碎,但气体压力过大会导致气体回流区影响范围增加,并向喷嘴中心孔(熔体下落通道)方向移动,可能会阻碍熔体下落,造成熔体喷溅;提高熔化室与雾化室气体压力差,能明显抑制气体回流区的形成,保证熔体顺利下落,但会使雾化室内气体射流速度下降,降低熔体破碎效果。     

承钢150m^2烧结机布料系统改造

介绍了布料系统改造前存在矿槽斗堵料、五辊布料的偏析性、透气性差、易掉辊、松料器的形状和布置不合理以及无压料器等问题。采取把称量斗和下部漏斗合并为一个斗、改五辊布料为九辊布料，改进联轴器、重新布置松料器、增加压料器等措施。解决了布料系统存在的问题，取得良好使用效果。     

基于微观机理的页岩气运移分析

认识气体在页岩孔隙中的运移机理对页岩气开采具有重要的科学意义.页岩作为一种致密岩石,孔隙尺寸分布主要集中在几纳米到百纳米之间,小孔隙尺寸与气体的平均分子自由程在同一个数量级,气体与孔隙边壁的碰撞对流动起到控制作用.本文针对页岩气开采过程中孔隙中气体流动过程,建立了考虑气体滑移、Knudsen扩散、Langmuir等温吸附、孔隙压缩等过程的多场耦合控制方程.分析了流态变化对滑移效应的影响,得到了考虑滑移效应的临界孔径,并针对实际中不同页岩储层有机质含量的差异,分析了解吸机制对页岩气产气率、产气量的贡献.研究还表明孔隙压缩性对产气率影响显著,通过考虑开采过程中孔隙压缩,可以更真实地反映页岩气运移过程.      

The Effects of Sample Position and Gas Flow Pattern on the Sintering of a 7xxx Aluminum Alloy

The effects of sample position and gas flow pattern on the sintering of a 7xxx aluminum alloy Al-7Zn-2.5Mg-1Cu in flowing nitrogen have been investigated both experimentally and numerically. The near-surface pore distribution and sintered density of the samples show a strong dependency on the sample separation distance over the range from 2?mm to 40?mm. The open porosity in each sample increases with increasing separation distance while the closed porosity remains essentially unchanged. A two-dimensional computational fluid dynamics (CFD) model has been developed to analyze the gas flow behavior near the sample surfaces during isothermal sintering. The streamlines, velocity profile, and volume flow rate in the cavity between each two samples are presented as a function of the sample separation distance at a fixed nitrogen flow rate of 6?L/min. The CFD modeling results provide essential details for understanding the near-surface pore distribution and density of the sintered samples. It is proposed that the different gas flow patterns near the sample surfaces result in variations of the oxygen content from the incoming nitrogen flow in the local sintering atmosphere, which affects the self-gettering process of the aluminum compacts during sintering. This leads to the development of different near-surface pore distributions and sintered densities.     

承钢150 m2烧结机布料系统的改进

为了提高烧结料层的粒度偏析和透气性，降低边缘效应，改善布料质量，对承钢150m^2烧结机布料系统进行了改进，包括：布料矿槽容积和形状的改进；五辊改九辊；重新布置松料器；增加压料器和九辊拦板等。改进后，取得了满意的效果。     

Factors influencing the production rate and quality of lead sinter

The sintering characteristics of a typical Missouri lead concentrate were determined for two types of raw sinter mix: conventionally prepared and pelletized. The important sintering characteristics are sulfur elimination, sinter strength, production rate of sinter, permeability of the sinter bed, and bed temperature. These characteristics were analyzed statistically, and are described by an empirical model, in which proportion of returns, moisture content, air flow, bed height, size distribution of returns, and ignition time are the independent variables. The characteristics of a conventionally prepared sinter mix are most strongly affected by the moisture content of the raw mix. The characteristics of a pelletized sinter mix are not strongly affected by any of the independent variables. However, a pelletized charge gave a much higher production rate and a higher sinter quality as compared to a conventionally prepared charge. Recycle of off gas has a large deleterious effect on sinter production rate and quality. The results provide suggestions for improved operation of sinter plants.     

烧结热风循环罩数值模拟与结构优化

为解决热风分布不均与罩内回流的问题,以首钢京唐500 m2烧结机热风循环系统的热风循环罩为研究对象,应用计算流体力学方法对其进行分析和优化.对热风循环罩原结构的流场数值模拟结果表明,热风从水平方向进入罩内后集中在来流方向远端一侧,来流方向近端一侧出现低速回流区,罩内热风分布严重不均,进入料面热风的最大速度达到了6.36...     

烧结矿孔洞结构对烧结强度的影响

通过微型烧结研究了3种精矿粉造成烧结矿粘结相中孔洞结构形成差异的原因,测试并分析了孔洞的尺寸和分布对烧结矿强度的影响。结果表明:烧结矿强度与孔洞形态、数量和尺寸有关;液相扩展能力过大或太差的矿粉都会在烧结过程中引起烧结矿内孔洞尺寸和数量的增加,从而影响其强度。     

分层供热富氢烧结关键技术探索与研究

 中国提出2030年碳达峰、2060年碳中和的“双碳”战略以缓解温室效应带来的环境问题。钢铁是仅次于火电的国内第二碳排放大户,作为钢铁行业中的核心环节,烧结工序的碳减排已是必然趋势。常规烧结工艺中,料层中固体颗粒燃料难准确满足“自蓄热效应”要求的“上多下少”的分布要求,导致料层内部供热不均、成矿质量差、能效低下,且易出现微观局部还原性气氛,对烧结成矿和烟气中CO增多造成负面影响,制约了烧结节能减碳水平的提升。对此,作者研究了燃料形态、燃料分布对烧结的影响规律,提出了“分层供热富氢烧结”理念,阐述了厚料层烧结条件下料层上、中、下各层不同的气固组合供热方法,即顶层依靠富氧点火耦合固体燃料供热、上中层依靠富氢燃气喷加耦合固体燃料供热,下层依靠水蒸气喷加耦合固体燃料供热,同时探明了对应该方法的分层供热低碳烧结机理,详细阐述了富氧点火耦合固体燃料顶层供热、富氢燃气喷加耦合固体燃料中上层供热、水蒸气喷加耦合固体燃料下层供热等关键技术及其技术效果,并对应用上述技术可能出现的烧结过湿层恶化问题提出了解决办法。通过这些技术的集成应用,可以大幅降低烧结工序能耗,减少烧结工序碳消耗、碳排放及其他污染物排放,并改善烧结矿质量。     

Variation of Flow Pattern with Sinuosity in Sine-Generated Meandering Streams

The effect of channel sinuosity on flow pattern in meandering streams is investigated. The centerlines of the idealized meandering streams under consideration follow sine-generated curves, and the banks are rigid; the flow is turbulent and subcritical. This study focuses on the vertically averaged flow over a flat (horizontal at any cross section) bed formed by a granular material. The “flat bed” is viewed as the initial surface of a moveable bed at the beginning of an experiment (at time t = 0). A series of laboratory flow measurements involving the systematic variation of the deflection angle θ0 from 30 to 110°, is used. It is found that every different sinuosity (every different θ0) has its own convective flow pattern, i.e., its own distribution in plan of (the L/2 long) convergence–divergence zones of flow. As θ0 increases, a gradual change in flow pattern is observed. Two expressions defining the observed θ0 variation of the convective flow pattern are introduced. It is shown, with the aid of the sediment transport continuity equation, that the geometry of the developed bed at the end of an experiment is strongly related to the convective behavior of the vertically averaged (initial) flow over the flat bed at t = 0. In particular, information on the θ0 variation of the convective pattern of the initial flow can be used to estimate the location of erosion–deposition zones and the location(s) of the most intense erosion–deposition corresponding to any θ0.     

Density Functions for Entrainment and Deposition Rates of Uniform Sediment

A model has been developed for the prediction of the density functions of bed-elevation and entrainment and deposition rates of sediment in sand bed streams within the lower regime flow condition. The model incorporates both statistical and deterministic parameters in its form. A total of 46 experimental runs have been carried out in a recirculating tilting flume under the equilibrium flow condition using three grain sizes of uniform gradation to validate the model and estimate its parameters. The model parameters are related to the hydraulic conditions of flow and fluid and sediment properties through dimensional and regression analyses. The study has shown that the density functions of bed elevation and entrainment and deposition rates can be approximated quite satisfactorily with the normal distribution curve. Transformation of the density functions into the standardized normal distribution curve provides a unique pattern for all the experimental runs regardless of the sediment grain size, flow condition, and shapes and dimensions of the bed forms. The developed density functions have been utilized to provide a closure for the probabilistic Exner equation for uniform sediment.