Effects of ultrasound on the desulfurization performance of hot coal gas over Zn-Mn-Cu supported on semi-coke sorbent prepared by high-pressure impregnation method

Zn-Mn-Cu/SC（U） sorbent was hydrothermally synthesized by ultrasound-assisted high-pressure impregnation method with semi-coke（SC）as support and the mixed solution of zinc nitrate,manganese nitrate and copper nitrate as active component precursors.The desulfurization performances of hot coal gas on the prepared sorbent at a mid-temperature of 500°C were tested in fixed-bed reactor.Morphology and pore structure of the prepared sorbent were also characterized by TEM,N2adsorption/desorption isotherms and XRD.For comparison,the sorbent of Zn-Mn-Cu/SC prepared by conventional high-pressure impregnation was also evaluated and characterized in order to study the effects of ultrasound treatment.Zn-Mn-Cu/SC（U） sorbent prepared by high-pressure impregnation under ultrasound-assisted condition showed a better desulfurization performance than Zn-Mn-Cu/SC.It could remove H2 S from 1000×10-6m3/m3 to 0.1×10-6m3/m3 at 500°C and maintained for 12.5 h with the sulfur capacity of 7.74%,in which both the breakthrough time and sulfur capacity were about 32% and 51% higher than those of Zn-Mn-Cu/SC sorbent.The introduction of ultrasound during high-pressure impregnation process greatly improved the morphology and pore structure of the sorbent.The ultrasonic treatment made particle size of active components smaller and made them more evenly disperse on semi-coke support,which provided more opportunities to contact with H2S in coal-based gases.However,there were no any difference in compositions and existing forms of active components on the Zn-Mn-Cu/SC and Zn-Mn-Cu/SC（U） sorbents.

Influence of load capacity on hydrostatic journal support deformation in finite element calculation

Based on the application of the four-oil-pad radial hydrostatic bearing in heavy equipments, the deformation of the four-oil-pad radial hydrostatic bearing was calculated by using the finite element method. The formula of film stiffness, film thickness and carrying capacity were established; the influence of the main parameters, such as load, load area and deformation on the supportability was analyzed; and the capacity of the two kinds of bearings was compared. The result shows that the carrying capacity of typeⅠ is prior to that of type Ⅱ . Calculations provide a theoretical basis for the bearing choosing and structure designing in the actual project.

Processing of AM60 magnesium alloy by hydrostatic cyclic expansion extrusion at elevated temperature as a new severe plastic deformation method

Hydrostatic cyclic expansion extrusion(HCEE) process at elevated temperatures is proposed as a method for processing less deformable materials such as magnesium and for producing long ultrafine-grained rods. In the HCEE process at elevated temperatures, high-pressure molten linear low-density polyethylene(LLDPE) was used as a fluid to eliminate frictional forces. To study the capability of the process,AM60 magnesium rods were processed and the properties were investigated. The mechanical properties were found to improve significantly after the HCEE process. The yield and ultimate strengths increased from initial values of 138 and 221 MPa to 212 and 317 MPa, respectively.Moreover, the elongation was enhanced due to the refined grains and the existence of high hydrostatic pressure. Furthermore, the microhardness was increased from HV 55.0 to HV 72.5. The microstructural analysis revealed that ultrafine-grained structure could be produced by the HCEE process. Moreover, the size of the particles decreased, and these particles thoroughly scattered between the grains. Finite element analysis showed that the HCEE was independent of the length of the sample, which makes the process suitable for industrial applications.

Simulation and experimental study on lubrication characteristics of vertical hydrostatic guide rails

In order to improve the cutting stiffness,the paper studies the vertical hydrostatic bearing in the slide when a ram is in feed process.The change of the oil film thickness on hydrostatic guide rail and the curve of the oil film thickness in various cutting forces are calculated and a relation model through theoretical analysis method is derived.The pressure field of the guide rail recess is simulated based on the finite volume method and demonstrated through experiments.The study is of vital theoretical significance for the improvement of machining accuracy of numerical control machines and the entire computer numerical control(CNC) equipment and provides valuable theoretical basis for the design of hydrostatic guide rail in engineering practice.

基于流固耦合的静压转台底部支撑优化

静压转台油腔的变形会降低静压转台的承载能力,底部支撑点的布局会显著影响油腔的变形量和底部支撑点的应变量。为了提高静压转台的工作能力,提出一种基于流固耦合的静压转台底部支撑布局重构方法。建立静压转台流固耦合模型,基于有限元方法得到静压转台在额定负载下油腔的变形量和底部支撑点处的应变量,利用MATLAB拟合底部支撑点半径和间距对变形和应变的影响规律,得到底部支撑布局的最佳参数。最后对静压转台底部布局进行重构,并通过试验验证其可靠性。结果表明:重构后油腔变形降低了约19.25%,底部支撑点处应变降低了约29.80%。

基于AMESim的大型磨齿机静压支承转台特性研究

为提升大型数控磨齿机的加工精度,研究了磨齿机静压支承转台的整体结构和工况以及分析了求解油膜厚度和输出流量的理论模型,初步得出了偏载对油膜厚度具有较大影响。为了进一步验证,在分析现有参数设计方法的基础上,利用AMESim软件建立系统模型,对不同工况和结构参数进行系统动态仿真分析。仿真结果表明:静压支承转台结构参数可以保证转台产生足够的承载力,流量脉动对油膜厚度变化率的影响不到0.4%,偏载对油膜厚度变化率的影响最大为13%,静态和动态仿真结果均与实际数据相符,性能测试结果满足磨床设计要求。

Impact of impregnation pressure on desulfurization performance of Zn-based sorbents supported on semi-coke

High-pressure impregnation, a new preparation method for sorbents to remove H2S from hot coal gas, is introduced in this paper. Semi-coke （SC） and ZnO is selected as the support and active component of sorbent, respectively. The sorbent preparation process includes high-pressure impregnation, filtration, ovendry and calcination. The aim of this research is to primarily study the effects of the impregnation pressure on physical properties and desulfurization ability of the sorbent. The desulfurization experiment was carried out in a fixed-bed reactor at 500 ~C and a simulated coal gas used in this work was composed of CO （33 vol%）, H2 （39 vol%）, H2S （300 ppm in volume）, and N2 （balance）. Experimental results show that the pore structure of the SC support can be improved effectively and ZnO active component can be uniformly dispersed on the support, with the small particle size of 10-500 nm. Sorbents prepared using high-pressure impregnation have better desulfurization capacity and their active components have higher utilization rate. P20-ZnSC sorbent, obtained by high-pressure impregnation at 20 atm, has the best desulfurization ability with a sulfur capacity of 7.54 g S/100g sorbent and a breakthrough time of 44 h. Its desulfurization precision and efficiency of removing H2S from the middle temperature gases can reach 〈 1 ppm and 〉99.7%, respectively, before sorbent breakthrough.

基于CNN-SVM的飞机EHA故障诊断算法研究

针对飞机电动静液作动器(electro-hydrostatic actuator,EHA)系统集成度高、工况复杂、故障种类多的特点,为了对其典型故障进行有效诊断,提出一种基于卷积神经网络(convolutional neural networks,CNN)和支持向量机(support vector machine,SVM)的故障诊断算法。使用CNN对故障数据进行自适应特征提取,再利用SVM对CNN全连接层输出进行分类。为提高SVM分类性能,使用带动态惯性权重的自适应粒子群优化算法(dynamic inertia weight adaptive particle swarm optimization,IWAPSO)实现对SVM参数的优化选择。引入Ramp损失函数降低SVM的噪声敏感性。结果表明:经过参数优化后的SVM准确率比标准SVM提升了12.6%,比传统CNN方法提升了17.3%;当使用含噪声信号的测试集时,基于Ramp损失函数的SVM表现出了更好的鲁棒性。

精密磨床电主轴静压滑动轴承的设计和优化研究

针对磨削精度的提升问题,对精密磨床电主轴静压支撑轴承进行设计和优化。设计的静压轴承为四油腔结构,节流方式为小孔节流,主要的设计参数包括节流比、半径间隙、回油槽宽度和封油面宽度等。建立了小孔节流静压滑动轴承的刚度计算模型,分析了节流比、半径间隙、回油槽宽度和封油面宽度对静压轴承支撑刚度的影响。采用正交实验的方法对轴承的节流比、半径间隙、回油槽宽度和封油面宽度进行优化设计,并通过极差分析获得以上四项参数对轴承刚度影响的主次顺序,从而获得最优的参数组合。研究结果表明:为半径间隙0.04mm,小孔节流比为1.8,回油槽宽度为12mm,封油面宽度为20mm,此时轴承的油膜刚度为最大值。文章的研究成果可为提升高精密加工机床的精度提供参考。

静压支撑单点渐进成形厚向应变分布研究

采用单点渐进成形技术单道次成形复杂形状的薄壁零件时,厚度分布不均匀及过度减薄易于引起板材的断裂和成形失效。将静压支撑引入单点渐进成形中,形成一种静压支撑单点渐进成形工艺;通过促进材料流动和厚向应变分布来提高板材厚度分布的均匀性。选用初始厚度为1 mm的1060铝板,以静压支撑单点渐进成形的圆锥台件为研究对象,通过数值模拟和实验研究分析了静压参数对厚向应变分布和材料流动规律的影响。结果表明:0~0.18 MPa的静压支撑有利于过渡变形区Ⅱ的快速成形,有利于主变形区Ⅲ的厚向应变分布;在有利压力范围内,静压压力越大,由Ⅱ区流向Ⅲ区的材料越多,厚向应变分布越均匀,制件成形性能越好。

Simulation and experimental analysis of supporting characteristics of multiple oil pad hydrostatic bearing disk

To study the heavy hydrostatic bearing with multiple oil pads, a reasonably simplified model of the pad is put forward, and the mathematical model of the bearing characteristics of the multiple oil pad hydrostatic bearing is built with consideration of variable viscosity. The pressure field in the clearance oil film of the hydrostatic bearing at various velocities is simulated based on the Finite Volume Method （FVM） by using the software of Computational Fluid Dynamics （CFD）. Some pressure experiments on the hydrostatic bearing were carried out and the results verified the rationality of the simplified model of the pad and the validity of the numerical simulation. It is concluded that the viscosity has a great influence on the pressure in the heavy hydrostatic bearing and cannot be neglected, especially, in cases of high rotating speed. The results of numerical calculations provide the internal flow states inside the bearing, which would help the design of the oil cavity structure of the bearing in engineering practice.

一种离心式压缩机的水压试验设计方案

阐述了一种离心式压缩机的水压试验方案。首先设计了水压密封工装与蜗壳装配使其形成密封空腔,随后确定了各结合面的密封方式以及连接方式,最后通过软件模拟了水压试验过程中工件的受力情况。结合工件结构及材质进行分析,对水压试验支顶方式进行了改进,解决了该产品因水压试验过程中工件变形导致尺寸超出图纸要求的问题,就该水压试验方案在实际生产中得到了应用和验证,为同行业生产制造大型离心式压缩机进行压力试验提供了实践依据。

水垫带式输送机的研究

在气垫带式输送机的基础上，提出了一种新型带式输送机——水垫带式输送机，与普通托滚式输送机相比，它具有运行阻力小、承载能力大、输送平稳、防火、安全可靠等特点，有很好的应用前景．对水垫静压润滑机理，水垫装置等关键零部件设计进行了详细的分析，并借助ＣＡＤ技术对水垫带式输送机进行了模拟设计，为实际应用提供了参考依据．

大型精密数控转台关键技术分析与应用

简要介绍了一种大型精密数控转台的主要结构特点,大型精密数控转台承重高达25t,可以实现连续回转、任意角度定位,分度精度高,可保证调头镗孔的同轴度。在开发过程中突破了精密传动和静压支撑两项关键技术,解决了传统数控转台定位精度和承载能力不高的技术难题。详细分析和论述了开发过程中突破的精密传动和静压支撑两项关键技术,解决了传统数控转台定位精度和承载能力不高的技术难题。

新型波形钢腹板支架结构平面内弹性屈曲性能分析

针对近年来提出的一种适用于软岩隧道(巷道)中的新型波形腹板金属支架支护结构,采用正交设计方法分析了静水压力下腹板厚度、腹板高度、翼缘宽度和厚度等截面参数对支架结构弹性屈曲性能的影响,得到了截面参数与支架结构1阶弹性整体屈曲荷载之间的函数关系。分析表明:翼缘宽度相同的情况下,随着波形腹板构件长细比的增加,支架整体屈曲荷载整体呈现减小趋势,且构件长细比的2次方与整体屈曲荷载呈反比;同一长细比下,随着构件翼缘宽度的增加,支架整体屈曲荷载基本呈现增长趋势;在此基础上分析马蹄形断面各半径对支架整体屈曲荷载的影响,进而推导出支架结构在静水压力下一阶弹性整体屈曲荷载的计算公式。

非静水压力条件下巷道围岩偏应力场分布特征与围岩破坏规律

通过理论分析对受三向应力非静水压力条件下的巷道围岩偏应力场与应变能密度分布规律进行了深入研究,以此来探究巷道围岩破坏规律,巷道塑性区数值模拟结果与现场工程实例验证了理论结果的正确性。研究结果表明:①非静水压力条件下,不同的主导型应力场中,巷道围岩偏应力场分布规律差异较为明显。σ_(x)主导型应力场中,巷道顶底板偏应力大于两帮;σ_(y)主导型应力场中,巷道顶底板与两帮偏应力大小差别不大;σ_(z)主导型应力场中,巷道两帮处的偏应力大于顶底板。主导应力值的变化会引起巷道围岩偏应力分布数值上的变化,不引起偏应力分布形态的改变。②等p、等q时,在σ_(x)与σ_(y)主导型应力场中,巷道顶底板应变能密度大于两帮,而在σ_(z)主导型应力场中,巷道两帮应变能密度大于顶底板。等p、不等q情况下,3种主导型应力场中,巷道顶底板与两帮应变能密度均随偏应力比M的增大而增大;等q、不等p情况下,巷道顶底板与两帮应变能密度均随偏应力比M的减小而增大。③三向应力状态下,巷道围岩应变能密度分布规律可以反映塑性区形态。M<1时,任意主导型应力场中,巷道围岩应变能密度呈椭圆形分布,M>1时,巷道围岩应变能密度呈“8”字形或“X”形分布。处于σ_(x)主导型应力场中的巷道需注重巷道顶底板的支护;对于σ_(y)主导型应力场,巷道在围岩条件较差时,应注重全断面支护;对于σ_(z)主导型应力场,需注意围岩塑性区出现“X”形扩展。④回坡底1021巷围岩偏应力场与应变能密度均呈倾斜的“8”字形分布,工程现场与巷道围岩偏应力场及应变能密度分布规律相互验证。基于理论分析结果,对回坡底1021巷提出非对称性支护技术,现场应用效果良好。

4m口径SiC反射镜原位检测用静压支撑系统

研制了一套用于4m SiC反射镜原位检测的静压支撑系统,以降低超大口径SiC反射镜离线检测的风险,提高其制造效率。首先,推导了单元刚度的解析式,确定了其中关键因素;然后,对支撑单元进行抽样测试,结合解析式预测了支撑群组中单元的工作刚度。最后,通过密封性测试和反射镜原位检测,验证了支撑系统的稳定性;通过有限元模拟,计算了系统的重力卸载面形精度。结果表明:5个单元连组时,单元刚度约为1.9kN/mm,刚度值分布在±3%误差区间;独立单元刚度可高至15kN/mm;3种分组单元刚度预测值分别为1.7,1.1和0.8kN/mm。支撑系统空载时管路压强变化缓慢,表明密封性良好;用该系统支撑4m反射镜时,11天内高度绝对变化量小于50μm,相对变化量小于20μm。54个单元刚度随机分布时,镜面面形高阶残差(RMS)为20nm。提出的系统基本满足原位检测的稳定性和精度要求。

4.5GPa静水压活塞圆筒式高压装置的应力检测分析及压力校正

本文提供了提高现有活塞圆筒式高压装置流体静压强的一种实验方法。成功地制做了锰铜丝压力计,并利用铋丝相变准确地做了压力校正。各箍的应力检测分析和相对位移测量都表明:无论压腔空载或充液时,在0.0001—3.08GPa均不显示出同步箍紧作用;上下缸的压强差偏大带来高压爆露的危险。为把流体静压强提高到 3.08 GPa以上,建议改进设计:(1)内箍中箍合二为一,外箍分为上下二层,将增加箍力;(2)调整各箍之间接触圆锥面的面积,将有助于同步箍紧;(3)增大密封套圈的无支承面,将减少上下缸压差,有利于安全运行。

内啮合齿轮泵内齿轮静压支撑研究

在分析内啮合齿轮泵发生胶合失效的形成机理的基础上,详细分析了内齿轮在运行过程中的受力情况,推导出了作用于内齿轮内壁的液压与啮合力所产生的合力在x、y两方向上的分力公式,通过MATLAB计算在一个受力周期内的内齿轮内壁受力情况,得到作用于其内壁的合力摆动中心线角度和平均合力大小。以此为基础,计算得到在泵体内壁开设静压支撑槽的位置。最后进行样机试验,试验结果表明,在输出液压力达到20MPa且主轴转速为1500r/min时齿轮泵工作正常,无胶合发生。

静压支承系统油膜特性分析

以静压支承系统中常见的矩形静压油垫为研究对象,计算并简化了其负载能力的理论公式,可近似等效为油液等压分布在由密封边中线围成的矩形区域上。在此基础上对油膜刚度进行了分析,发现其是油源参数、结构尺寸等相关的复杂函数,且设计状态参数ηo存在一个理论最优值,使得油膜刚度最大。