磨料浆液除锈系统的研究

本文利用后混合磨料射流的工作原理进行了磨料浆液除锈系统的试验。并分析了压力、靶距、横移速度、磨料供给量、水流量、磨料粒度和磨料种类对除锈效率的影响，为磨料浆液除锈各参数的选择提供了参考。试验表明，压力是影响除锈效率最重要的参数。     

冷态钢材的旋转磨料水射流除鳞除锈能耗研究

作业效率和比能耗是评价冷态钢材水射流除鳞除锈能力的重要因素.本文研制大直径旋转磨料水射流除鳞除锈基本作业单元,以解决传统的超高压纯水旋转射流的高能耗和传统的磨料水射流的低效率的缺点,并进行了三者除锈试验,试验表明旋转磨料水射流除鳞除锈技术的能耗优于传统的水射流除鳞除锈技术.     

钢渣型喷砂除锈材料的研究与应用开发

为开发一种非金属钢渣型喷砂除锈材料,对钢渣的基本性能,及其作为非金属磨料的加工工艺、应用技术、应用性能进行研究分析。祥细分析了钢渣的化学成分、硬度、压碎值和颗粒分布,并提出了加工钢渣成为除锈料的方法。与传统材料铜矿砂、铁丸喷砂进行比对,加工过的钢渣性能与非金属磨料相近,可满足各项除锈磨料的技术要求。钢渣型喷砂除锈料在船厂的除锈工程应用实践中证明,钢渣喷砂除锈可以达到Sa2.0的等级,循环使用次数高于铜矿砂,除锈性能与铜矿砂相近,可以在普通修船厂应用。     

前混合磨料连续水射流钢材除鳞除锈系统分析

钢材在深度加工前有的需要对钢材表面除鳞、除锈及污垢清洗,这对钢材的质量有着重要的影响。介绍一种新型前混合磨料连续水射流除鳞除锈系统,对前混合磨料连续水射流的工作原理、组成、磨料水射流流动原理及前混合磨料连续水射流除鳞除锈系统进行了分析。     

技术市场

经过精细加工后的铜渣,是一种质地优良的钢铁表东面除锈磨料,它具有硬度高、效果好、无毒害、价格低等特点。经造船、桥梁等行业使用表明,这种磨料是船舶、桥梁、石油化工、水电等部门最佳的除锈材料。随着国内     

湿法抛砂除锈理论分析与原理探究

首先分析了国内外带钢表面除锈技术的应用现状,比较了各类除锈方式的优缺点,在此基础上,提出了湿法抛砂除锈的工艺理论,并通过对湿法抛砂的工作原理、浆体磨料的生产方式以及湿法抛砂工艺对带钢表面性能影响的主要参数等几个方面的深入研究分析,得出湿法抛砂除锈是一项非常环保的机械除锈新技术。     

后混合磨料水射流除鳞喷嘴内部流场数值模拟

基于CFD多相流欧拉模型,针对后混合式磨料水射流除鳞喷嘴中磨料与水混合均匀性差、射流能量利用率低的缺点,应用Fluent软件对磨料侧进式、切进式和平行多射流式3种进料方式的喷嘴进行三维数值模拟,通过喷嘴内部流场速度矢量图分析了3种进料方式下高压水与磨料的作用机理,并通过磨料体积分数云图比较了流场的均匀性.结果表明:与磨料侧进式喷嘴相比,磨料切进式和平行多射流式喷嘴能够改善磨料与水的混合效果,使流场内磨料分布均匀.但切进式喷嘴会增加喷嘴内部的磨损,需要采用更耐磨的材料.与前两种喷嘴相比,平行多射流式喷嘴可得到磨料与水最好的混合均匀性,实际应用中还可以根据需要对水射流的流量及作用方式进行调节.     

高压水射流技术的应用前景

高压水射流技术的基本原理就是高压泵产生具有一定压力的水流,通过增压元件和高聚能喷咀的作用,转化为不等能量和不同形状的高压射流,以达到满足清洗、切割、破碎、穿透等作业的应用要求。如果在水射流中掺入细磨料颗粒形成磨料射流,则可大大提高水射流的压力和冲击力。     

无酸除鳞技术在冷轧宽带应用的探索与实践

通过对无酸清洗技术进行研究,结合高压射流在窄带除鳞、金属除锈等方面的应用情况,探索无酸除鳞清洗技术在冷轧宽板生产的应用。     

前混合磨料水射流除鳞喷嘴混合腔内部流场

基于计算流体动力学多相流混合物模型,应用FLUENT软件对前混合磨料水射流除鳞喷嘴高压水与磨料混合腔内部流场进行数值模拟.比较了不同进料方式对流场均匀性的影响.分析了两侧为高压水入口条件下,磨料入口直径、高压水入口直径、高压水入口位置和角度以及收缩段锥角对流场混合均匀性的影响,得到了影响混合腔内部流场混合均匀性的合理结构参数.数值计算结果表明:入口速度一定的条件下,磨料中进式喷嘴混合腔的混合均匀性优于磨料侧进式喷嘴混合腔.随磨料入口和高压水入口直径增加,混合腔出口的射流速度均增加,但随高压水入口直径增加导致出口磨料浓度呈先增后减的趋势,磨料入口与高压水入口合理的质量流量比值约为3∶4,两侧高压水入口位置对流场混合均匀性影响较小,高压水入口角度和收缩段锥角均为30°时流场性能更佳.      

热镀锌机组沉没辊轴套磨损机理分析

通过光学、电子金相等手段分析了热镀锌机组上曾使用过的低碳合金钢及耐热钢轴套的腐蚀与磨损状况，发现轴套材料表面受锌腐蚀而形成高硬度的Ａｌ－Ｆｅ－Ｚｎ块状相，推断轴套因受腐蚀和磨粒磨损的联合作用而失效。     

Frictional properties of materials based on dense modifications of boron nitride

Conclusions For all of the dense modifications of boron nitride under conditions of loading by friction upon reaching the critical sliding rate a qualitative change in the frictional characteristics is observed. On the working surface of the abradant a film is formed, which obviously is an indication of transformation of the sphalerite and wurtzite phases into the graphitelike one with subsequent oxidation of it and the formation of low-melting iron borates.By changing the ratio of the content of dense modifications of boron nitride (BN_sph and BN_w) it is possible to control the critical value of V within a wide range of sliding rates, thereby obtaining the optimum combination of frictional characteristics, which is of significant value in practical machining of materials.Translated from Poroshkovaya Metallurgiya, No. 9(261), pp. 82–87, September, 1984.     

Effect of methane-hydrogen mixtures on flow and combustion of coherent jets

Coherent jets are widely used in electric arc furnace(EAF)steelmaking to increase the oxygen utilization and chemical reaction rates.However,the influence of fuel gas combustion on jet behavior is not fully understood yet.The flow and combustion characteristics of a coherent jet were thus investigated at steelmaking temperature using Fluent software,and a detailed chemical kinetic reaction mechanism was used in the combustion reaction model.The axial velocity and total temperature of the supersonic jet were measured via hot state experiments.The simulation results were compared with the experimental data and the empirical jet model proposed by Ito and Muchi and good consistency was obtained.The research results indicated that the potential core length of the coherent jet can be prolonged by optimizing the combustion effect of the fuel gas.Besides,the behavior of the supersonic jet in the subsonic section was also investigated,as it is an important factor for controlling the position of the oxygen lance.The investigation indicated that the attenuation of the coherent jet is more notable than that of the conventional jet in the subsonic section.     

Experiments on Vertical Turbulent Plane Jets in Water of Finite Depth

Detailed experiments on vertical turbulent plane jets in water of finite depth were carried out in a two-dimensional water tank. The jet velocities were measured with a laser Doppler velocimeter (LDV). The LDV measurement covers the entire flow regime: the zone of flow establishment (ZFE), the zone of established flow (ZEF), the zone of surface impingement (ZSI), and the zone of horizontal jets (ZHJ). From the experimental results, the following conclusions are reached. First, the jet flow is independent of the Reynolds number if the Reynolds number is sufficiently large to produce a turbulent jet. Second, in the initial ZFE, the jet flow is nonsimilar and is characterized by the two free shear layers along the two edges of the jet orifice. Third, the jet flow in ZEF is self-similar. Both mean and fluctuation velocities are scaled with the mean jet centerline velocity. The turbulent shear stress is predictable by Prandtl's third eddy viscosity model. The spreading of the confined vertical jets is larger than that of a free jet, so is the faster decay of jet centerline velocity. Fourth, in ZSI the jet flow is nonsimilar and high turbulent intensities were found. The vertical turbulent jet transforms into two opposite horizontal surface jets after the impingement. And finally, the maximum velocity of the horizontal surface jet in ZHJ decays according to a power law.     

Dispersion of Neutrally Buoyant Horizontal Round Jet in Wave Environment

The behavior of a neutrally buoyant turbulent round jet located at the middepth discharging horizontally into a shallow water wave environment was investigated. Regular progressive waves with relatively small wave amplitudes were used in the study. The instantaneous velocity field of the turbulent jet was measured using the particle image velocimetry (PIV) technique. Phase average was used to extract the mean velocity from the PIV measurements. The jet longitudinal and cross-sectional profiles were used to demonstrate the effect of wave dispersion on jet diffusion. Five different wave amplitudes were used to show the effects of wave amplitude, while three different wave phases were also used to check the phase effect on the jet. The results suggest that the influence of wave amplitude on jet diffusion is very significant while the influence of wave phase is relatively small.     

环境温度对超音速氧气射流特性影响的数值模拟

通过数值模拟的方法研究了不同环境温度条件下超音速氧气射流的特性,并与前人的实验结果进行了对比分析.研究结果表明:与低温环境条件相比,高温环境条件下超音速氧气射流的速度衰减受到抑制,射流核心段长度得到延长;不同环境温度条件下,氧气射流的温度随着氧气射流的扩散不断升高,最终趋于环境温度;射流的压力分布趋势与射流速度分布趋势一致.数值模拟得到的射流速度、温度和压力结果与实测值吻合度较高.      

环境压力对超音速氧气射流特性影响的数值模拟

超音速氧气射流技术是炼钢精炼过程中的重要环节,关于常压条件下超音速氧气射流的特性已进行了大量的研究,但对真空精炼过程中低压环境下的超音速氧气射流特性目前研究较少。通过数值模拟的方法研究了不同环境压力条件下超音速氧气射流的特性,并与试验结果进行了对比分析。研究结果表明：低压环境条件与高压环境条件相比,超音速氧气射流速度的衰减受到抑制,射流核心段的长度得到延长;不同环境压力条件下,射流压力与射流速度分布趋势一致,均沿轴向不断降低,但压力衰减程度大于速度衰减的程度;不同环境压力条件下,氧气射流的温度随着氧气射流的扩散不断升高,最终趋于环境温度。     

存在倾角的平面射流收缩及运动轨迹

通过理论推导和水力学模型实验给出了存在倾角的平面射流收缩计算模型及运动轨迹,得到了平面射流在宽度方向上的收缩角与出口速度、射流初始厚度的关系。这不仅对平面射流反应器的研究开发很有意义,而且对薄板坯连铸的研究也有一定的借鉴作用。     

Field Measurements of Mean Velocity Characteristics of a Large-Diameter Swirling Jet

Full-scale field acoustic Doppler velocimeter measurements of the radial, axial, and tangential flow components were undertaken in a large-diameter turbulent swirling jet generated by a raft-mounted axial flow-mixing propeller discharging through a draft tube during isothermal and stratified conditions. The results were compared with classical jet theory and showed significant differences in the zone of flow establishment though similar behavior in the zone where established flow was found. It was concluded that the efflux from the axial flow-mixing propeller could not be described adequately by conventional jet theory due to the jet size and swirling characteristics.