聚焦超声雾化栽培喷头设计及工作频率对雾化效果的影响研究

气雾培是当下解决植物根系水气矛盾的一种优化栽培模式,为了克服已有的雾化栽培中高频超声雾化器存在雾化量小、雾滴分布不均、雾化可靠性差等缺点,研究了一种新型的聚焦球壳超声雾化栽培喷头,通过理论分析、公式推导设计了聚焦球壳超声雾培喷头的主要结构尺寸,利用有限元分析软件ANSYS对雾培喷头的结构参数进行模态分析和验证,研究其在不同的工作频率下对雾培效果的影响。试验表明该雾化器的雾化效果比较好,基本满足雾化栽培的需要,并且发现超声频率对雾化喷头的雾化效果产生一定影响。     

聚焦超声雾化栽培喷头设计及工作频率对雾化效果的影响研究（英文）

气雾培是当下解决植物根系水气矛盾的一种优化栽培模式,为了克服已有的雾化栽培中高频超声雾化器存在雾化量小、雾滴分布不均、雾化可靠性差等缺点,研究了一种新型的聚焦球壳超声雾化栽培喷头,通过理论分析、公式推导设计了聚焦球壳超声雾培喷头的主要结构尺寸,利用有限元分析软件ANSYS对雾培喷头的结构参数进行模态分析和验证,研究其在不同的工作频率下对雾培效果的影响。试验表明该雾化器的雾化效果比较好,基本满足雾化栽培的需要,并且发现超声频率对雾化喷头的雾化效果产生一定影响。     

大口径厚壁管挤压力理论公式推导、计算机模拟与验证

应用新的力学模型(镦粗式力学模型)推导出大口径厚壁管垂直挤压的挤压力理论计算公式,并与其它力学模型下导出的公式相比较.该公式能够反映挤压力与挤压高度之间的函数关系,而其它公式则不能.同时,还对该公式进行了计算机模拟,模拟表明:利用镦粗式力学模型推导出的公式与模拟结果基本一致,也与生产实际相符.该力学模型更符合大口径厚壁...     

圆孔翻边极限翻边系数的计算

根据板料屈服极限与断面收缩率的关系,推导出圆孔翻边时极限翻边系数的近似计算公式。     

板料拉力下弯曲回弹分析

通过对板料拉力下弯曲应力状态的分析,根据回弹理论,推导了回弹角与拉力之间关系的近似计算公式。     

中厚板轧制展宽新公式推导及其应用

分析了中厚板的轧制过程,建立了变形方程,推导了中厚板轧制展宽新公式。该公式反映了中厚板各轧制阶段间钢板尺寸的关系,其计算精确,有利于轧制过程控制、钢坯安排、压下规程设定,以及板形和平面形状控制。同时,介绍了该公式的使用方法。     

工业用氟化铝中氟含量计算公式的推导及应用

论述了工业用氟化铝的来源及氟化铝中各元素之间的组成关系,并从理论上推导出氟的计算公式和分析了此公式计算时可能存在的几种形式,并讨论了公式在生产分析中的应用。     

板带矫直机辊缝的确定

矫直板带时,其弯曲量和辊缝的关系,迄今国内尚无现成的公式可供计算,也没有详细图表可供查阅。本文推导了一个辊缝值理论公式。作者曾用此公式计算了武钢1700热轧厂IHI摆式飞剪13辊矫直机的辊缝值,其结果与日本给出的操作图表完全相符。     

高孔率金属延伸率的理论计算

运用几何学与力学推导各同性高孔率材料的孔率与延伸率的近似关系。通过对高孔隙率发泡镍的实验,证明了理论公式与实际结果一致。     

超声检测中表面粗糙度引起的声衰减补偿

在超声检测中，被检工件表面粗糙度不同导致耦合损耗不同，往往使探伤灵敏度降低。目前常用的补偿耦合损耗的方法是根据材质制作对比试块，但该方法费时费力。根据大平底回波声压公式推导出了工件表面粗糙度和补偿量之间的关系，可直接通过计算得到表面粗糙度引起的衰减量。制作了具有不同表面粗糙度的对比试块，通过试验验证了推导公式的正确性。     

往复扫描喷射沉积过程中雾化器运动的研究

雾化器运动是雾化器往复扫描喷射沉积过程中一个非常重要的因素。研究了雾化器往复扫描喷射沉积过程中雾化器的运动，总结了不同的喷射距离下，雾化器喷射密度函数的分布以及雾化器在扫描过程中运动速度v与沉积锭坯半径R之间的关系。在雾化器往复扫描喷射沉积过程中，根据对雾化器运动的研究进行数值模拟，实现了喷射沉积过程的工艺优化，为进一步研究喷射沉积过程提供了理论依据，对于工业生产也具有指导意义。     

A 3D simulation of two-phase flow in an effervescent atomizer for suspension plasma spray

In the suspension spray of nanoparticles, where the attempt is to reach nano-scaled uniform coatings, there is a vital demand to produce a controllable and non-pulsating spray. Effervescent atomizers, in which a gas is bubbled into the bulk of liquid through an aerator, have shown to be a technological alternative to the conventional atomizers when liquid atomization with various concentrations of nano-particles is required. Thus, understanding the behavior of gas and liquid flow through the nozzle is crucial to predict the condition of resultant spray. The two-phase flow inside an effervescent atomizer is numerically investigated. Using an incompressible Eulerian/Eulerian approach, the three-dimensional structure of two-phase flow inside an aerated-liquid injector is modeled. The behaviour of liquid film carrying nano-particles in the discharge passage is studied using different Gas to Liquid mass flow Ratios (GLR), ranging from 0.08% to 1.25%. These numerical results are compared with the experimental data available in literature. The effect of nano-sized solid particles concentration on the liquid film thickness at the exit of the atomizer is studied through the change in liquid bulk density and viscosity. The results show that the atomizing gas-to-liquid mass flow ratio (GLR) does play a key role on the flow behaviour inside the atomizer. At low GLRs of 0.15%, the thickness of the liquid film decreases rapidly and as GLR increases to 1.25% the liquid film thickness dependency on GLR reduces. The results also show that there is no significant effect of particle concentrations, varying within the range of Newtonian fluid, on the liquid film thickness. This feature makes effervescent atomizers a technology choice for controllable suspension thermal spray processes.     

喷雾热分解法制备超细银粉及其形貌控制

采用超声雾化热分解装置,对喷雾热分解法制备超细银粉进行了系统研究。考察了炉子温度、硝酸银水溶液浓度、超声雾化装置功率、硝酸银溶液及载气流量等因素对产物粒子形貌、粒度分布的控制行为。研究结果证实,喷雾热分解制备微米级球形金属银粉技术具有广泛应用前景。     

新型喷涂涡轮永磁轴承结构设计与力学特性

针对轿车覆盖件高速离心喷涂涡轮机的开发,设计了一种新型的双环径向永磁轴承,建立了力学模型,提出了一种磁力和刚度的计算方法,并进行了模拟仿真和实验验证,为涡轮的进一步理论分析以及设计开发提供了理论指导依据.     

覆砂铁型铸造工艺的铁型冷却装置

通过特制的喷嘴，利用压缩空气的喷射在出水口形成负压，把水吸出后使水雾化，用来冷却热铁型。水的喷射强度和流量大小可通过阀门调节。这种冷却装置可有效地降低铁型温度，铁型冷却均匀，延长使用寿命，改善工作环境。     

Reheat response and accelerated cooling of a microalloyed steel with an air/water atomizer: Effect on microstructure and mechanical properties

The use of an atomizer for accelerated cooling is discussed. An atomizer is an effective tool for controlling the microstructure and properties of a microalloyed steel because of its flexibility of operation and control of cooling rate over a broad range of temperatures. Some basic issues regarding heat transfer in pool boiling and in spray cooling also are presented. Reheating response studies were conducted in addition to studies of the effect of accelerated cooling on the microstructure and properties of a low- carbon steel microalloyed with niobium and vanadium. This steel produces a tempered martensitic microstructure on quenching and a predominantly bainitic microstructure at slower cooling rates. The yield, tensile, and fracture strengths can be tailored by controlling the cooling rate, which in turn can be controlled by the air/water ratio and flow rates in the atomizer. Impact toughness is a function of cooling rate and reaches a maximum followed by a decrease,probably due to the formation of upper bainite at lower cooling rates. Fractographic studies indicated that tensile fracture occurred by microvoid coalescence, with the dimple size decreasing as the cooling rate decreased. Charpy impact fracture studies indicated that the primary mode of failure was by quasi- cleavage, with the number of secondary cracks also decreasing as the cooling rate decreased.     

种分法制备超细氢氧化铝过程中的粒度控制

超细氢氧化铝具有许多优点,应用广泛。超细氢氧化铝的粒度分布和颗粒形貌对产品的性能有很大影响。根据湿化学法颗粒成核与生长机理从理论上分析了超细氢氧化铝制备过程中需控制的工艺条件,研究了二段分解工艺中晶种添加量和温度等对分解产品粒度分布的影响,得出了温度和种子添加量对氢氧化铝粒度分布的影响规律。     

三水铝石矿溶出指标优化的探讨

进口三水铝石矿用于拜耳法生产氧化铝,以其低能耗,低成本为国内氧化铝生产行业所青睐。本文通过对矿石成分、溶出工艺等研究分析,得出相对合理经济的溶出条件。     

Simulation of Effervescent Atomization and Nanoparticle Characteristics in Radio Frequency Suspension Plasma Spray

In this paper, a comprehensive model was developed to investigate the suspension spray for a radio frequency (RF) plasma torch coupled with an effervescent atomizer. Firstly, the RF plasma is simulated by solving the thermo-fluid transport equations with electromagnetic Maxwell equation. Secondly, primary atomization of the suspension is solved by a proposed one-dimensional breakup model and validated with the experimental data. Thirdly, the suspension droplets and discharged nanoparticles are modeled in Lagrangian manner, to calculate each particle tracking, acceleration, heating, melting and evaporation. Saffman lift force, Brownian force and non-continuum effect are considered for nanoparticle momentum transfer, as well as the effects of evaporation on heat transfer. This model predicts the nanoparticle trajectory, velocity, temperature and size in the RF suspension plasma spray. Effects of the torch and atomizer operating conditions on the particle characteristics are investigated. Such operating conditions include gas-to-liquid flow ratio, atomizer orifice diameter, injection pressure, power input level, plasmas gas flow rate, and powder material. The statistical distributions for the multiple particles are also discussed for different cases.     

雾化器往复扫描喷射共沉积制备6066/SiCp坯锭技术

提出了雾化器往复扫描喷射共沉积制备6066／SiCp的装置和方法，并与传统的喷射共沉积装置进行了比较。采用了螺旋给料陀螺负压引流乏气送粉装置和分离式双环缝雾化器来加入SiC颗粒增强相，制备了大规格的6066／Sicp复合材料坯锭。