Wetting front migration model of ion-adsorption rare earth during the multi-hole unsaturated liquid injection

In the process of ion-adsorption rare earth ore leaching,the migration characteristics of the wetting front in multi-hole injection holes and the influence of wetting front intersection effect on the migration distance of wetting fronts are still unclear.Besides,wetting front migration distance and leaching time are usually required to optimize the leaching process.In this study,wetting front migration tests of ionadsorption rare earth ores during the multi-hole fluid injection(the spacing between injection holes was 10 cm,12 cm and 14 cm)and single-hole fluid injection were completed under the constant water head height.At the pre-intersection stage,the wetting front migration laws of ion-adsorption rare earth ores during the multi-hole fluid injection and single-hole fluid injection were identical.At the postintersection stage,the intersection accelerated the wetting front migration.By using the Darcy’s law,the intersection effect of wetting fronts during the multi-hole liquid injection was transformed into the water head height directly above the intersection.Finally,based on the Green-Ampt model,a wetting front migration model of ion-adsorption rare earth ores during the multi-hole unsaturated liquid injection was established.Error analysis results showed that the proposed model can accurately simulate the infiltration process under experimental conditions.The research results enrich the infiltration law and theory of ion-adsorption rare earth ores during the multi-hole liquid injection,and this study provides a scientific basis for optimizing the liquid injection well pattern parameters of ion-adsorption rare earth in situ leaching in the future.

Influence of the Hole Chamfer on the Characteristics of a Multi-hole Orifice Flowmeter

In order to analyze the influence of the hole chamfer on the metering performances of a Multi-hole Orifice Flowmeter and optimize the related orifice structure,a multi-hole orifice flowmeter with DN80 and throttle ratio of 0.45 was considered in the present study.The flow field characteristics were determined in the framework of a CFD technique.The results show that the multi-hole orifice flowmeter with filleting transition around the throttle orifice has higher accuracy in a wide range of the space of parameters,and is more suitable for accurate measurement of fluid in process control.

Single-mode low threshold current multi-hole vertical-cavity surface-emitting lasers

A multi-hole vertical-cavity surface-emitting laser （VCSEL） operating in stable single mode with a low threshold current was produced by introducing multi-leaf scallop holes on the top distributed Bragg-refleetor of an oxidation- confined 850 nm VCSEL. The single-mode output power of 2.6 mW, threshold current of 0.6 mA, full width of half maximum lasing spectrum of less than 0.1 nm, side mode suppression ratio of 28.4 dB, and far-field divergence angle of about 10% are obtained. The effects of different hole depths on the optical characteristics are simulated and analysed, including far-field divergence, spectrum and lateral cavity mode. The single-mode performance of this multi-hole device is attributed to the large radiation loss from the inter hole spacing and the scattering loss at the bottom of the holes, particularly for higher order modes.

A new analytical-numerical method for calculating interacting stresses of a multi-hole problem under both remote and arbitrary surface stresses

Based on the elementary solutions and new integral equations,a new analytical-numerical method is proposed to calculate the interacting stresses of multiple circular holes in an infinite elastic plate under both remote stresses and arbitrarily distributed stresses applied to the circular boundaries.The validity of this new analytical-numerical method is verified by the analytical solution of the bi-harmonic stress function method,the numerical solution of the finite element method,and the analytical-numerical solutions of the series expansion and Laurent series methods.Some numerical examples are presented to investigate the effects of the hole geometry parameters(radii and relative positions)and loading conditions(remote stresses and surface stresses)on the interacting tangential stresses and interacting stress concentration factors(SCFs).The results show that whether the interference effect is shielding(k<1)or amplifying(k>1)depends on the relative orientation of holes(α)and remote stresses(σ^∞x,σ^∞y).When the maximum principal stress is aligned with the connecting line of two-hole centers andσ^∞y<0.5σ^∞x,the plate containing two circular holes has greater stability than that containing one circular hole,and the smaller circular hole has greater stability than the bigger one.This new method not only has a simple formulation and high accuracy,but also has an advantage of wide applications over common analytical methods and analytical-numerical methods in calculating the interacting stresses of a multi-hole problem under both remote and arbitrary surface stresses.

Optimization Design of Multi-hole and Varied Diameter Pipe Based on RAGA

Combining real accelerating genetic algorithm(RAGA) with the optimization design of multi-hole and varied diameter pipe, the authors solved the problem of optimizing multi-dimensional parameters at the same time. In which the advanced convergence and easily to run into partial optimization were avoid. Applied the RAGA to solving the problem in the optimization design of fixed piping sprinkler irrigation system. The optimized parameters, such as diameters and the length of pipe were calculated and the result was reasonable, which provides as a reference to readers who work at related research.

Development of a biliary multi-hole self-expandable metallic stent for bile tract diseases: A case report

BACKGROUND Uncovered stents used for malignant obstructions in the biliary tree, especially in the hilar area, are prone to obstruction by tumor ingrowths. In comparison, however, covered stents may block bile duct branches and are at risk of migration. We have developed a multi-hole self-expandable metallic stent (MHSEMS), with a hole in each cell, to prevent the obstruction of bile duct branches. In addition, the holes may prevent migration due to small ingrowths by reducing the tension of the membrane. CASE SUMMARY MHSEMS were placed in five patients with a malignant obstruction and one with post-endoscopic sphincterotomy bleeding. Each MHSEMS was successfully deployed in all cases. Patients showed no complications. Two cases were reviewed. Case 1: A 74-year-old male presented with jaundice and was diagnosed with a sigmoid colon cancer and giant liver metastases in the right liver lobe. A MHSEMS was placed in the left bile duct. The jaundice improved and peroral cholangioscopy was performed. Case 2: A 90-year-old female was admitted to hospital for jaundice and diagnosed with cholangiocarcinoma. A MHSEMS was placed in the left bile duct but after 8 months the stent became obstructed by tumor ingrowth. We treated the patient by ablation therapy. A silicone cover separated the internal bile duct from the surrounding tissue, protecting the latter from thermal injury during treatment by endobiliary ablation of the reobstruction. CONCLUSION A MHSEMS is a new choice of stent for biliary tract diseases.

Effect of an Internal Heat Exchanger on the Performances of a Double Evaporator Ejector Refrigeration Cycle

A theoretical investigation is presented about a double evaporator ejector refrigeration cycle(DEERC).Special attention is paid to take into account the influence of the sub-cooling and superheating effects induced by an internal heat exchanger(IHX).The ejector is introduced into the baseline cycle in order to mitigate the throttling process losses and increase the compressor suction pressure.Moreover,the IHX has the structure of a concentric counter-flow type heat exchanger and is intentionally used to ensure that the fluid at the compressor inlet is vapor.To assess accurately the influence of the IHX on the DEERC performance,a mathematical model is derived in the frame of the dominant one-dimensional theory for ejectors.The model also accounts for the friction effect in the ejector mixing section.The equations of this model are solved using an Engineering Equation Solver(EES)for different fluids.These are:R134a as baseline fluid and other environment friendly refrigerants used for comparison,namely,R1234yf,R1234ze,R600,R600a,R290,R717 and R1270.The simulation results show that the DEERC with an IHX can achieve COP(the coefficient of performance)improvements from 5.2 until 10%.

Stability Analysis of a Multi-holes Shell Under Axial Compression

The paper presents a multi-holes shell with one hundred and eighty circular holes which has been used in engineering. Using a buckling module of the finite element analysis software, stability behavior and destroy mode along geometry parameters are studied. Results show the destroy mode depends on the geometry parameter greatly. Curves of buckling critical load and strength limited load along geometry parameters have a point of intersection. The point implies the multi-holes shell has different destroy mode and the value of point is change in geometry parameters.

基于CFD和响应面法的引射器优化设计

针对质子交换膜燃料电池(Proton Exchange Membrane Fuel Cell, PEMFC)氢气引射器优化研究中优化精度低、忽视多结构耦合作用的问题,采用CFD和响应面法结合优化引射器结构参数。通过单因素仿真试验研究各结构对引射比的影响,在此基础上设计正交试验构建响应面分析多结构参数交互作用。研究结果表明:喷嘴距和等压混合室直径的响应p值小于0.05,存在耦合作用且对引射性能具有显著影响,通过响应面法优化后引射器最大引射比达到3.62,相比于单因素优化结果提升了25.69%并且预测模型误差仅为4.93%。

乏汽供热用大型蒸汽射汽器性能试验与研究

对乏汽供热用大型射汽器的性能进行了全面分析和研究。结合射汽器的固有特性,在300 MW等级机组的乏汽供热系统中对射汽器变工况性能进行了试验研究,得到了不同机组背压、动力蒸汽压力和出口压力下射汽器的性能曲线。建立了一种射汽器全工况特性的性能参数求解方法。结果表明:性能参数求解结果与试验数据吻合度高。

冷却通道对引射器红外辐射特性影响的研究

为降低燃气轮机排气系统中的引射器排气温度,从而减少排出燃气的红外辐射强度,本文提出了一种具有冷却通道的亚音速引射器结构,并提出了评价冷却通道引射器的综合系数。在原有的引射器喷嘴内增加冷却通道,使冷气直接与主流中心位置的高温气体掺混,破坏排气包覆性分布,达到提高主流温度均匀性、降低中心温度的目的。本文运用数值模拟的方法,研究引射器内冷却通道数量、冷却通道进深和排气通道的排布对引射器内阻力特性、换热特性、出口温度分布特性的综合影响。研究结果表明:单排冷却通道排布时,通道数量与换热特性成正比,与阻力损失成反比;双排冷却通道排布时,阻力损失降低。双排12通道引射器可有效降低出流总温,均匀主流温度,综合系数最高。

改良成人经口气管插管机械通气患者口腔护理方法及应用

目的探讨改良成人经口气管插管机械通气患者口腔护理方法的应用效果。方法便利抽样选取2021年1月1日至2021年12月30日四川省人民医院神外监护室经口气管插管机械通气患者220例为对照组,口腔护理方法为冲洗+擦拭+吸痰管连接负压吸引;2022年1月1日至2022年12月30日经口气管插管机械通气患者163例为观察组,口腔护理方法为擦拭+冲洗+吸唾管连接负压吸引。比较两组患者口腔异味发生率、口腔污垢残留、操作时口腔内污液溢出及吸唾管/吸痰管滑出情况、呼吸机相关性肺炎发生率。结果两组患者呼吸机相关性肺炎发生率比较差异无统计学意义(P>0.05);两组口腔异味发生率、口腔污垢残留、操作时口腔内污液溢出及吸唾管/吸痰管滑出、操作耗时等比较,差异有统计学意义(P<0.05);100%操作人员愿意选择观察组的吸唾管连接负压吸引口腔护理废液(P<0.05)。结论改良成人经口气管插管机械通气患者口腔护理方法,能提高口腔护理质量、提高患者舒适度,节约成本、提高工作效率,有一定的推广应用价值。

结构参数对气液下喷式喷射器性能的影响研究

喷射环流反应器是一种新型的气液或气液固接触反应装置,其中的喷射器结构会对反应器性能产生重要影响。文章采用计算流体力学方法,建立了文丘里型喷射器的数学模型,分析了吸气室、喉部和扩散段等结构对喷射器吸气量的影响规律。模拟结果表明:吸气室直径和气相入口方式对吸气量影响不大;喷嘴与喉部之间距离越小,喉部长度越短,吸气量越高;扩散段扩散角度在2~4°之间时吸气量存在最大值。

异形分流管热流道家族注塑模具设计

介绍了某款异形分流管零件热流道注塑模具的设计过程。模具设计中,首先,分析了注塑件的零件特征和生产要求,确定了模具的基本结构方案;再利用Moldflow软件分析模具注塑成型过程,预测零件的成型时间、翘曲变形量、熔接痕位置等,最终完成整套模具的设计。模具采用两板式热流道冷浇口注塑成型,浇口选择潜伏式点浇口形式,开模时自动拉断与注塑件分离;模具定模型腔设计了1个弹性脱模镶件,保证了开模时塑件紧贴型芯侧;模具分型面上共分布了5个侧抽芯滑块结构,由弯销导向并延时开模。对常用型弯销滑块机构进行了改进,将两段式弯销改进为三段式弯销,有效地避免了常用弯销滑块机构容易出现卡死和锁闭不紧的问题。模具经过实际生产验证可知,结构合理可靠,制备得到的零件尺寸精度满足设计要求。

基于夹点的带喷射器CO_(2)热泵系统性能分析

为了研究带喷射器的跨临界CO_(2)内部过冷热泵系统(TCISE),基于夹点建立了TCISE的热力学模型,分析了冷却水进出水温度及流量对系统性能的影响。研究表明:冷却水进水温度从25℃降低到15℃时,最优高压压力从9.3 MPa降至8.8 MPa,降低了5.4%,最大COP从3.83提升至4.27,提高了11.49%;TCISE存在临界冷却水出水温度和临界冷却水质量流量,当冷却水进水温度一定时,在出水温度低于临界出水温度或质量流量高于临界质量流量时,系统COP保持不变。

引射器真空度的设计与研究

为满足大型电解槽精准出铝、减少电解槽散热要求,需要提高引射器的真空度。本文参考了目前理论研究的最新结果并结合经验数据,设计出引射器的内部结构。根据减少动能损失而提高真空度的原理提出了调整压缩空气压力、喷嘴至收缩段的距离和喷嘴直径这三个主要参数值的方法,按此最佳参数值设计出的引射器经试验测试当进口压缩空气压力为0.65 MPa时,真空度最大达到-0.068 MPa。

A novel method for simulating nuclear explosion with chemical explosion to form an approximate plane wave: Field test and numerical simulation

A nuclear explosion in the rock mass medium can produce strong shock waves,seismic shocks,and other destructive effects,which can cause extreme damage to the underground protection infrastructures.With the increase in nuclear explosion power,underground protection engineering enabled by explosion-proof impact theory and technology ushered in a new challenge.This paper proposes to simulate nuclear explosion tests with on-site chemical explosion tests in the form of multi-hole explosions.First,the mechanism of using multi-hole simultaneous blasting to simulate a nuclear explosion to generate approximate plane waves was analyzed.The plane pressure curve at the vault of the underground protective tunnel under the action of the multi-hole simultaneous blasting was then obtained using the impact test in the rock mass at the site.According to the peak pressure at the vault plane,it was divided into three regions:the stress superposition region,the superposition region after surface reflection,and the approximate plane stress wave zone.A numerical simulation approach was developed using PFC and FLAC to study the peak particle velocity in the surrounding rock of the underground protective cave under the action of multi-hole blasting.The time-history curves of pressure and peak pressure partition obtained by the on-site multi-hole simultaneous blasting test and numerical simulation were compared and analyzed,to verify the correctness and rationality of the formation of an approximate plane wave in the simulated nuclear explosion.This comparison and analysis also provided a theoretical foundation and some research ideas for the ensuing study on the impact of a nuclear explosion.

车用燃料电池引射器设计及测试评价方法研究

在研究开发车用燃料电池引射器时,湿氢流量监测困难、台架技术难度大、试验成本高,并且存在安全隐患和能源浪费问题。为此,在推导空气与氢气、空气与100%RH的氢在相同工作条件下的流量变化关系式的基础上,针对110 kW燃料电池,试制引射器进行空气和氢气测试,并结合数值仿真分析。结果发现:车用燃料电池引射器引射流体中水蒸气质量分数达到40%~50%;在相同工作条件下,空气与氢气的体积和质量流量分别等于其气体常数比值的平方根和比值倒数的平方根,其中空气与氢气的体积和质量流量之比分别为3.786和0.2641。工作、引射和混合流体质量流量的空气实测与仿真数据之间的平均相对误差分别为4.48%、4.54%和2.78%;空气实测数据经折算后与氢气测试数据相吻合,与湿氢的仿真数据平均偏差率分别为5.4%和6.11%;氢气测试数据经折算也与湿氢仿真数据相吻合。因此,空气测试数据经处理可以用于车用燃料电池引射器特性研究。

-30至50℃车辆工况下CO_(2)喷射器的适应性研究

为推动喷射器回收膨胀功技术的实车应用,本文开展了-30~50℃宽温区运行工况下车用压缩-引射式CO_(2)热泵系统制冷制热性能及喷射器膨胀功回收特性研究,重点分析了工作喷嘴对固定尺寸喷射器变工况适应性的影响。结果表明:制冷工况下随着环境温度升高,喷射系数递减,而升压比递增;制热工况下随着环境温度降低,喷射系数和升压比均先增大后减小;制冷工况下喷射器回收膨胀功占最大可回收膨胀功的16.7%~37.2%,制热工况下为9.9%~41.3%;以高温制冷工况设计的固定尺寸喷射器难以适应低温制热工况,偏离设计工况时,喷嘴出口过膨胀会造成激波能量损失,而低温制热工况下喷嘴出口因欠膨胀会导致喷射器无引射效果。

应用于新型环路热管的两相引射器数值模拟

环路热管是一种高效被动式相变传热装置,广泛应用于高热流电子器件散热等领域。前期研究发现将小型两相引射器与平板式环路热管耦合,可大幅提高传热性能。然而,小型两相引射器内部流动及传热机理尚不清晰,难以对新型环路热管进行正向设计与理论建模。通过数值模拟研究了汽水参数和混合腔结构对两相引射器性能及内部流场分布的影响。结果表明,喉部下游存在凝结激波,随着背压增加,其位置逐渐向喉部移动;其强度与背压、蒸汽产量、混合腔长度呈正相关,与水温呈负相关。引射器最大工作背压在40~125 kPa,与蒸汽产量和水温呈正相关,与混合腔长度呈负相关。通过大量模拟,得到了设计功率下水温和混合腔长度对引射器工作模式和压比的影响规律。