Floating Clamping Mechanism of PT Fuel Injector and Its Dynamic Characteristics Analysis

PT fuel injector is one of the most important parts of modern diesel engine.To satisfy the requirements of the rapid and accurate test of PT fuel injector,the self-adaptive floating clamping mechanism was developed and used in the relevant bench.Its dynamic characteristics directly influence the test efficiency and accuracy.However,due to its special structure and complex oil pressure signal,related documents for evaluating dynamic characteristics of this mechanism are lack and some dynamic characteristics of this mechanism can＇t be extracted and recognized effectively by traditional methods.Aiming at the problem above-mentioned,a new method based on Hilbert-Huang transform（HHT） is presented.Firstly,combining with the actual working process,the dynamic liquid pressure signal of the mechanism is acquired.By analyzing the pressure fluctuation during the whole working process in time domain,oil leakage and hydraulic shock in the clamping chamber are discovered.Secondly,owing to the nonlinearity and nonstationarity of pressure signal,empirical mode decomposition is used,and the signal is decomposed and reconstructed into forced vibration,free vibration and noise.By analyzing forced vibration in the time domain,machining error and installation error of cam are revealed.Finally,free vibration component is analyzed in time-frequency domain with HHT,the traits of free vibration in the time-frequency domain are revealed.Compared with traditional methods,Hilbert spectrum has higher time-frequency resolutions and higher credibility.The improved mechanism based on the above analyses can guarantee the test accuracy of injector injection.This new method based on the analyses of the pressure signal and combined with HHT can provide scientific basis for evaluation,design improvement of the mechanism,and give references for dynamic characteristics analysis of the hydraulic system in the interrelated fields.

High-pressure synthesis,mechanical properties,and oxidation behavior of advanced boron-containingα/β-Si_(3)N_(4)/Si ceramics using polymer-derived amorphous SiBN ceramics

The preparation of dense Si_(3)N_(4)-based ceramics has attracted great attention because of the achievable improvements in their mechanical properties and high-temperature oxidation resistance.In this work,advanced dense boron-containingα/β-Si_(3)N_(4)/Si monoliths were prepared via a high pressure‒high temperature technique in which polymer-derived amorphous SiBN powders were used as raw materials.The crystallization behavior and phase transformation of the polymer-derived amorphous samples were studied in the temperature range from 1400 to 1800℃.The results demonstrate that the incorporation of boron in the Si_(3)N_(4)matrix suppresses the phase transformation fromα-Si_(3)N_(4)toβ-Si_(3)N_(4).Furthermore,the mechanical properties of the as-prepared samples were measured,and the maximum hardness and fracture toughness of boron-rich SiBN samples reached 14.8 GPa and 7.96 MPa·m1/2,respectively.The hardness of the obtained boron-rich SiBN samples is stable up to 300℃.In addition,the oxidation behavior of the samples prepared at 1400 and 1600℃ was investigated at 1400℃ for 50 h.The results show that the incorporation of boron significantly improved the oxidation resistance of the samples because of the formation of borosilicate/cristobalite.This work provides guidance for the synthesis of boron-containingα/β-Si_(3)N_(4)-based ceramics with excellent mechanical properties and oxidation resistance.

High-pressure capacity expansion and water injection mechanism and indicator curve model for fractured-vuggy carbonate reservoirs

Water injection for oil displacement is one of the most effective ways to develop fractured-vuggy carbonate reservoirs.With the increase in the number of rounds of water injection,the development effect gradually fails.The emergence of high-pressure capacity expansion and water injection technology allows increased production from old wells.Although high-pressure capacity expansion and water injection technology has been implemented in practice for nearly 10 years in fractured-vuggy reservoirs,its mechanism remains unclear,and the water injection curve is not apparent.In the past,evaluating its effect could only be done by measuring the injection-production volume.In this study,we analyze the mechanism of high-pressure capacity expansion and water injection.We propose a fluid exchange index for high-pressure capacity expansion and water injection and establish a discrete model suitable for high-pressure capacity expansion and water injection curves in fractured-vuggy reservoirs.We propose the following mechanisms:replenishing energy,increasing energy,replacing energy,and releasing energy.The above mechanisms can be identified by the high-pressure capacity expansion and water injection curve of the well HA6X in the Halahatang Oilfield in the Tarim Basin.By solving the basic model,the relative errors of Reservoirs I and II are found to be 1.9%and 1.5%,respectively,and the application of field examples demonstrates that our proposed high-pressure capacity expansion and water injection indicator curve is reasonable and reliable.This research can provide theoretical support for high-pressure capacity expansion and water injection technology in fracture-vuggy carbonate reservoirs.

Microstructure and mechanical properties of high-strength high-pressure die-cast Mg–4Al–3La–1Ca–0.3Mn alloy

A new high-pressure die-cast(HPDC) Mg–4 Al–3 La–1 Ca–0.3 Mn(ALaX431) alloy with high strength has successfully been fabricated. This HPDC alloy in peakaged state exhibits tensile yield strength(TYS) of 220 MPa at room temperature and TYS of 145 MPa at 250 ℃,higher than the corresponding strength of HPDC Mg alloys reported so far. These high strengths are mainly due to the formation of fine grained structure, semi-continuous reticular structure consisting of stable Al_(3)La and(Mg,Al)2 Ca particles along grain boundaries and numerous nanoscale Al_(2)Ca precipitates within grains. Due to its higher strength than existing HPDC Mg alloys, the new developed alloy has great application potential.

Application of high-pressure technology in exploring mechanical properties of high-entropy alloys

In recent years,high-entropy alloys(HEAs) have developed a lot as the new style of materials,which have become a research focus in the materials fields.It breaks the normal procedure of traditional alloy design(based on one/two elements as the main component,and adds some other elements to improve the micro structure and required related performance of the alloy),and consists of five or more equal or nearly equal elements,with multiple principal elements.Therefore,HEAs have many excellent mechanical properties compared with traditional alloys,which have aroused great research interest of researchers.The rapid development of high-pressure technology makes it a powerful tool to modulate the structures of HEAs,and brings new chance for the study and optimization of mechanical properties of HEAs.In this paper,the application of high-pressure technology in exploring and improving the mechanical properties of HEAs is reviewed,which could deepen the understanding of high-pressure technology and provide a new avenue for further exploration of HEAs’ mechanical properties.

Microstructures and mechanical properties of a newly developed high-pressure die casting Mg-Zn-RE alloy

A newly developed Mg-4Zn-2La-3Y alloy with high strength was fabricated by high-pressure die casting method,and its microstructures were thoroughly studied using transmission electron microscopy.The results demonstrate that it owns fine grains and approximately highly interconnected intermetallic phase skeletons,and exhibits ultra-high strength at both room and high temperatures.Interestingly,the eutectic intermetallic skeleton of this alloys is consisted of numerous fine particles,which are mainly consisted of two intermetallic phases,namely W and Mg12RE.Multiple{101}twins and SFs were found in the Mg12RE phase while a few of SFs in the W phase.Additionally,minor long-period stacking ordered phase was observed in the eutectoid phase,and it probably nucleated on the Mg12RE phase following a certain OR as(0002)14H//(110)Mg12REand[1120]14H//[111]Mg12RE,or(0002)14H//(211)Mg12REand[1120]14H//[111]Mg12RE.This special intermetallic skeleton with many interfaces and planar faults can efficiently transfer dislocations across grain boundaries,and this is the key factor for the outstanding mechanical properties of the studied alloy.

Research on thermal insulation materials properties under HTHP conditions for deep oil and gas reservoir rock ITP-Coring

Deep oil and gas reservoirs are under high-temperature conditions,but traditional coring methods do not consider temperature-preserved measures and ignore the influence of temperature on rock porosity and permeability,resulting in distorted resource assessments.The development of in situ temperaturepreserved coring(ITP-Coring)technology for deep reservoir rock is urgent,and thermal insulation materials are key.Therefore,hollow glass microsphere/epoxy resin thermal insulation materials(HGM/EP materials)were proposed as thermal insulation materials.The materials properties under coupled hightemperature and high-pressure(HTHP)conditions were tested.The results indicated that high pressures led to HGM destruction and that the materials water absorption significantly increased;additionally,increasing temperature accelerated the process.High temperatures directly caused the thermal conductivity of the materials to increase;additionally,the thermal conduction and convection of water caused by high pressures led to an exponential increase in the thermal conductivity.High temperatures weakened the matrix,and high pressures destroyed the HGM,which resulted in a decrease in the tensile mechanical properties of the materials.The materials entered the high elastic state at 150℃,and the mechanical properties were weakened more obviously,while the pressure led to a significant effect when the water absorption was above 10%.Meanwhile,the tensile strength/strain were 13.62 MPa/1.3%and 6.09 MPa/0.86%at 100℃ and 100 MPa,respectively,which meet the application requirements of the self-designed coring device.Finally,K46-f40 and K46-f50 HGM/EP materials were proven to be suitable for ITP-Coring under coupled conditions below 100℃ and 100 MPa.To further improve the materials properties,the interface layer and EP matrix should be optimized.The results can provide references for the optimization and engineering application of materials and thus technical support for deep oil and gas resource development.

Preparation of Fe-As alloys by mechanical alloying and vacuum hot-pressed sintering:microstructure evolution,mechanical properties,and mechanisms

Arsenic materials have attracted great attention due to their unique properties.However,research concerning iron-arsenic(Fe-As) alloys is very scarce due to the volatility of As at low temperature and the high melting point of Fe.Herein,a new Fe-As alloy was obtained by mechanical alloying(MA) followed by vacuum hot-pressed sintering(VHPS).Moreover,a systematic study was carried out on the microstructural evolution,phase composition,leaching toxicity of As,and physical and mechanical properties of Fe-As alloys with varying weight fractions of As(20%,25%,30%,35%,45%,55%,65%,and 75%).The results showed that pre-alloyed metallic powders(PAMPs) have a fine grain size and specific supersaturated solid solution after MA,which could effectively improve the mechanical properties of Fe-As alloys by VHPS.A high density(> 7.350 g·cm^(-3)),low toxicity,and excellent mechanical properties could be obtained for FeAs alloys sintered via VHPS by adding an appropriate amount of As,which is more valuable than commercial Fe-As products.The Fe-25% As alloy with low toxicity and a relatively high density(7.635 g·cm^(-3)) provides an ultra-high compressive strength(1989.19 MPa),while the Fe-65% As alloy owns the maximum Vickers hardness(HVo.5 899.41).After leaching by the toxicity characteristic leaching procedure(TCLP),these alloys could still maintain good mechanical performance,and the strengthening mechanisms of Fe-As alloys before and after leaching were clarified.Changes in the grain size,micro structure,and phase distribution induced significant differences in the compressive strength and hardness.

磁共振增强扫描专用注射器的应用及护理体会

目的 探讨磁共振专用注射器的使用操作及护理。方法 本组共 172例 ,年龄 15～ 70岁 ,平均 43 .8岁 ,使用美国Medrad Spectris磁共振增强扫描专用注射器和GD DTPA造影剂 ,规范操作规程。 结果 本组一次成功 165例 ,不同原因失败 7例 ,扫描过程及 2 4h内 167例无任何异常 ,5例出现各种不适。结论 磁共振专用注射器推注造影剂配合磁共振增强扫描是准确、安全、可靠的。规范操作 ,熟练掌握机器性能 ,提高护理质量是检查成功的关键。

光谱技术仿真分析发动机沉积物生成的化学机理

尝试利用所建立的实验室尺度沉积物生成仿真装置模拟不同壁面温度下的喷嘴沉积物生成过程,并用傅里叶转换红外线光谱仪(FTIR)分析沉积物生成的化学机理,探讨汽油中组成物质与抗沉积物添加剂在不同含量下对沉积物生成机理的影响。结果证实本仿真分析方法可快速有效的预先评价添加剂的作用,并且筛选出汽油成分中可能生成沉积物的物质。

连续管作业注入头夹持机理研究

对连续管作业注入头夹持机理进行了分析,将夹持力简化为沿周向正弦分布的压力,利用级数形式的应力函数、应力边界条件和位移连续条件得到不规则外压作用下的应力分布,给出了连续管内、外表面关键点处的等效应力随着夹持力、轴向拉力、内压、连续管壁厚和外径变化而变化的规律:①等效应力随着夹持力的增大而迅速增大;②除了轴向拉力很小的情况以外,等效应力随轴向拉力F的增大而增大;③在连续管的不同位置,内压对等效应力的影响趋势不同。在内表面θ=0点和外表面θ=π/2点的等效应力随内压的增大而减小;而内表面θ=π/2和外表面θ=0点的等效应力随内压的增大而增大;④随着壁厚的增大连续管内、外表面的等效应力均有所减小;⑤在壁厚和夹持力一定时,等效应力随外径的增大出现先减小后增大的趋势;⑥随着内压由小逐渐增大,屈服极限曲线出现先外移后内移的现象,且弹性区的范围随着内压的增大逐渐减小。

高压涡旋喷油器喷雾撞壁机理研究

为了研究直喷式汽油机高压涡旋喷油器喷雾撞壁机理,测量了撞壁喷雾的高度、喷雾半径及喷雾远端速度,分析了不同喷射压力、环境背压、喷嘴到壁面的距离、壁面倾角等因素对撞壁喷雾的影响。随着喷射压力、喷嘴到壁面的距离及壁面倾角的增加,喷雾的贯穿距离增大;环境背压的增大导致喷雾的贯穿距离减小。较高的喷射压力和较低的环境背压增大了撞壁燃油与壁面的接触面积,在壁面上形成的薄膜加速了燃油的蒸发。由经验公式计算得到的撞壁喷雾贯穿距离与试验测量值在一定范围内具有一致性,为燃烧室的设计、进气道形式的选取、喷油器和火花塞的布局提供了试验依据。

大港复杂断块油藏港西油田套损机理及预防对策

截至2008年底，港西油田发现套损井578口，严重影响了油田开发效果，套损已经成为制约油田正常生产的重要因素。为搞好港西油田二次开发，完善注采井网，采用统计分析、理论研究和综合对比方法，系统研究套损机理，并提出预防对策。以港西五区为研究对象，开展了套损基本形态研究，统计分析了油水井套损名义寿命、套损程度、套损深度与套损点数的规律。并研究该区的地质特征，通过建立套损综合分析图，构建了11种套损分析地质模型。同时，分析了钻井“狗腿”、固井质量、套管钢级等工程因素以及油田开发方式、注水压力、综合含水等开发因素与套损的关系。通过系统研究，搞清了套损形态和套损规律，确定了港西油田套损的主控因素为泥岩水化，以此提出了有效的套损预防措施，为港西油田二次开发和生产管理提供了科学依据。

连续油管注入头夹紧机构力学分析

浮动压板和链条滚子是注入头夹紧机构中两个主要的受力零件,在使用过程中常出现损坏的情况。对夹紧机构进行了ADAMS多刚体动力学分析,得到了链条滚子质心和浮动压板铰接孔处的载荷变化规律。计算得到链条滚子质心处垂直于浮动压板方向上出现最大载荷时,浮动压板和链条滚子的相对位置。对浮动压板和链条滚子进行了ANSYS有限元接触分析,得到了二者接触区域的应力分布情况,找到了链条滚子和浮动压板各自最大应力出现的位置及原因。以上分析结果,为夹紧机构的优化设计提供了一定的理论依据。

气藏型地下储气库建库注采机理与评价关键技术

气藏型地下储气库是目前全球最主要的地下储气库类型,其工作气量约占全球各类储气库总工作气量的75%。为了提高气藏型地下储气库(以下简称储气库)建库地质方案设计的科学性和可靠性、优化储气库运行参数,从储气库多周期大流量强注强采的基本特点出发,综合采用物理模拟和数值模拟两种技术手段,重点研究了复杂地质条件气藏改建储气库圈闭动态密封性和气水高速交互渗流机理,建立了盖层、断层动态密封性评价和库容参数评价的关键技术。研究结果表明:(1)储气库注采工况交变应力对盖层原始静态毛细管密封和力学完整性具有不同程度的弱化作用,采用动态突破压力、剪切安全指数等指标可以全面量化评价圈闭的密封性;(2)基于高速注采互驱实验揭示的孔隙局部动用机理,建立了以有效含气孔隙为基础的储气库库容量设计方法。矿场应用实例表明,该技术应用于大型多层H储气库,有效指导了储气库建库地质方案设计,该储气库经过5个周期注采后达容率为91.8%,调峰能力由投产初期的2.7×10~8 m^3快速增至36.3×10~8 m^3,运行指标与方案设计吻合程度高。

力平衡法测量大气压强

依据力平衡法原理,重新构思、设计了测量大气压强的实验方案及装置,力学传感器的使用,提高了大气压强测量中的关键物理量的测量精度;采用最小二乘法,实现了大气压强的巧妙测量.

恒温器箱形真空壳体的研制

ADS加速器旨在解决核能可持续发展中的"增殖核材料和嬗变核废物"问题。通过理论计算及数值模拟相结合的方法,设计了ADS加速器低温恒温器的真空壳体,真空壳体内部尺寸为4 200 mm×1 500 mm×1 500 mm的箱形结构。根据真空壳体密封性能及强度要求,介绍了真空壳体焊缝的结构设计。最后根据真空壳体尺寸精度及尺寸稳定性要求,着重介绍了真空壳体的制造工艺过程。恒温器箱形真空壳体经实际检测,各项性能满足设计要求。

弱碱三元复合驱动态特征及其对驱油效果影响

弱碱三元复合体系在油藏多孔介质内结垢不仅会增大流动阻力、减少吸液量，而且会影响油水井生产动态特征，进而影响复合驱增油效果。依据复合驱提高采收率原理，通过分析油水井生产和测试资料，归纳和总结了弱碱三元复合驱动态反映特征。结果表明，成垢作用是造成注入压力升高、吸液量下降、吸液和产液剖面变化的主要原因。在复合驱初期，成垢作用可以改善吸液剖面、扩大波及体积，但中后期它却是加快“吸液剖面反转”的主要因素。分析研究还发现，成垢作用可以改善油井产液剖面、增加中低渗透层剩余油动用程度。

用振荡流体力学方法分析气液喷嘴内流体振荡的传播规律

应用振荡流体力学方法研究气液喷嘴内流体振荡的传播规律，通过将气相和液相的非定常基本方程转化为振幅方程而联立求解振幅量的方法，确定气液喷嘴内在不同流动工况条件下流体振荡的传播规律。研究成果对于分析各类喷嘴内的流体振荡现象的原因及其改进方法有重要的意义。

MR高压注射器在增强扫描中的应用

目的探讨MR高压注射器的在增强扫描中的应用问题。方法本组600例,年龄46—78岁,平均64岁,其中男114例,女486例。使用德国Ulich磁共振高压注射器和造影剂GD—DTPA。结果本组589例患者顺利完成(98%),2例患者血管显影欠佳(0.3%),5例患者出现药液渗漏失败(0.8%),3例患者因造影剂筒针尖露出液面出现空气报警(0.5%),1例因汞用管管道出现渗漏,而不得不重新安装(0.1%)。所有检查病人均无出现不适。结论熟练掌握磁共振高压注射器的使用能有效高质完成MR的检查,也是MR检查成功的关键之一。