Theoretical Analysis and Experimental Verification on Valve-less Piezoelectric Pump with Hemisphere-segment Bluff-body

Existing researches on no-moving part valves in valve-less piezoelectric pumps mainly concentrate on pipeline valves and chamber bottom valves, which leads to the complex structure and manufacturing process of pump channel and chamber bottom. Furthermore, position fixed valves with respect to the inlet and outlet also makes the adjustability and controllability of flow rate worse. In order to overcome these shortcomings, this paper puts forward a novel implantable structure of valve-less piezoelectric pump with hemisphere-segments in the pump chamber. Based on the theory of flow around bluff-body, the flow resistance on the spherical and round surface of hemisphere-segment is different when fluid flows through, and the macroscopic flow resistance differences thus formed are also different. A novel valve-less piezoelectric pump with hemisphere-segment bluff-body （HSBB） is presented and designed. HSBB is the no-moving part valve. By the method of volume and momentum comparison, the stress on the bluff-body in the pump chamber is analyzed. The essential reason of unidirectional fluid pumping is expounded, and the flow rate formula is obtained. To verify the theory, a prototype is produced. By using the prototype, experimental research on the relationship between flow rate, pressure difference, voltage, and frequency has been carried out, which proves the correctness of the above theory. This prototype has six hemisphere-segments in the chamber filled with water, and the effective diameter of the piezoelectric bimorph is 30mm. The experiment result shows that the flow rate can reach 0.50 mL/s at the frequency of 6 Hz and the voltage of 110 V. Besides, the pressure difference can reach 26.2 mm H20 at the frequency of 6 Hz and the voltage of 160 V. This research proposes a valve-less piezoelectric pump with hemisphere-segment bluff-body, and its validity and feasibility is verified through theoretical analysis and experiment.

Effect of insulin pump and continuous intravenous insulin on ketone body metabolism, blood gas indexes and stress state in patients with diabetic ketoacidosis

Objective:To study the effect of insulin pump and continuous intravenous insulin on ketone body metabolism, blood gas indexes and stress state in patients with diabetic ketoacidosis. Methods:Patients with diabetic ketoacidosis who were treated in Meizhou Maternal and Child Heath Hospital between May 2014 and March 2017 were selected as the research subjects and randomly divided into the group A who received subcutaneous insulin infusion by insulin pump and the group B who received intravenous small-dose insulin injection by micropump. The indexes of ketone body, blood gas and stress were measured before and after treatment. Results: 12 h and 24 h after treatment, serumβ-hydroxybutyrate, MDA, NE, ACTH and Cor contents of both groups of patients were significantly lower than those before treatment while pH, HCO3- and base excess levels as well as serum SOD, GSH-Px, CAT and TAC contents were significantly higher than those before treatment, and serumβ-hydroxybutyrate, MDA, NE, ACTH and Cor contents of group A were significantly lower than those of group B while pH, HCO3- and base excess levels as well as serum SOD, GSH-Px, CAT and TAC contents were significantly higher than those of group B.Conclusion:Subcutaneous insulin infusion by insulin pump can improve ketone body metabolism, acidosis status and stress state in patients with diabetic ketoacidosis.

Study on Key Joining Technology and Test Method of Steel/Al Hybrid Structure Body-in-White

Green and low carbon promote the application and development of light-weight materials in body-in-white. Large-scale die-casting Al alloy (DCAA) and high-strength thermo-formed steel sheet (TFSS) have put forward higher requirements for the application of joining technology of high-strength steel/Al dissimilar materials. Taking the new die-casting Al alloy body as an example, this paper systematically studies the progress of the latest joining methods of steel/Al dissimilar material with combination of two-layer plate and three-layer plate. By analyzing the joining technologies such as FSPR, RES, FDS and SPR, the technology and process characteristics of steel/Al dissimilar material joining are studied, and the joining technical feasibility and realization means of different material combination of the body are analyzed. The conditions of material combination, material thickness, material strength, flange height, preformed holes and joint spacing for achieving high-quality joining are given. The FSPR joining technology is developed and tested in order to meet with the joining of parts with DCAA and TFSS, especially for the joining of three-layer plates with them. It finds the method and technical basis for the realization of high quality joining of dissimilar materials, provides the early conditions for the application of large DCAA and TFSS parts in body-in-white, and meets the design requirements of new energy body. .

Microstructure and properties of ductile iron bars for plunger pump prepared by horizontal continuous casting process

Ductile iron bars(DIBs) with a diameter of 145 mm, used for plunger pump production, were made by the horizontal continuous casting(HCC). The microstructure of the samples cut at three locations with different distances away from the surface(~20 mm from the surface, half of the radius and the center of the HCCDIBs)were investigated. The mechanical properties were measured by tensile and torsion tests. Results show that after the spheroidization of graphite, the iron matrix incorporates the nodules of Format I, Size 8 close to the surface, Format I, Size 7 at the half of the radius from the surface, and Format II, Size 6 in the centre of the bar,according to the ASTM A247 standard. The content of pearlite in the matrix changes from 55%(~20 mm from the surface) to 70%(half of the radius) and 80%(the center of the HCCDIBs). The strengths in tension are 552, 607 and 486 MPa with the elongations of 12.5%, 10.5% and 5.8% in samples cut at these three locations from the surface to the centre, respectively. The strength in torsion is equal to 558, 551 and 471 MPa at corresponding torsion angles of 418°, 384° and 144° respectively to the same distance from the bar surface. Fracture in tension is manifested via crack propagation through the interface between graphite nodules and matrix(Mode I), while in torsion the fracture is caused by the shear of graphite nodules(Mode II). It is shown that the transition between two fracture modes is also dependent on the size of graphite nodule. Typically, fracture Mode I was observed for nodules of smaller diameter(less than 22.7 μm) and fracture Mode II was seen for nodules of greater diameter(more than 24.8 μm).

Microstructure and Property of Hypereutectic High Chromium Cast Iron Prepared by Slope Cooling Body-Centrifugal Casting Method

In this paper, the ring-type ingot of hypereutectic high Cr cast iron was obtained by slope cooling bodycentrifugal casting method （SC-CCM）, and its microstructure and impact toughness were investigated, respectively. The results indicated that, first, the primary carbides in the microstructure are prominently finer than those in the hypereutectic high Cr cast iron prepared by conventional casting method. Second, in the ring-type ingot, the primary carbides near radial outer field are finer than those near radial inner field; furthermore, there is dividing field in the microstructure. Finally, the impact toughness values of the specimens impacted on the radial outer face and on the radial inner face are improved respectively about 36% and 138% more than that of the hypereutectic high Cr one prepared by conventional casting method.

基于Multibody的3缸往复柱塞泵系统仿真

Multibody是Matlab 2016a及以后版本中新增的多体系统建模仿真模块,与其他动力学仿真软件相比,具有操作简单、直观灵活、适用性广等特点。为对接国内高校普遍开设的《机械原理课程设计》,以3缸往复柱塞泵为例:建立了3缸往复柱塞泵的理论模型;利用Multibody构建了3缸往复柱塞泵仿真模型;对理论模型和仿真模型进行了对比分析,完成飞轮设计,对比结果验证了Multibody仿真的准确性与可行性。研究工作为"机械原理课程设计"教学提供了新思路,对后续利用Multibody开展仿真研究具有参考意义。

Casting process design and practice for coolant pump impeller in AP1000 nuclear power station

The coolant pump impeller casting is the only rotating component in the nuclear island of an AP1000 nuclear power station, and is required to have a 60-year service time, which requires advanced materials and processing technologies to guarantee. In this paper, the casting process was studied, designed and modified by means of numerical simulation. The gating system was distributed symmetrically and the runner diameter was a little bigger for avoiding sand wash and turbulence;the feeding system focused on the solution of blades feeding, as some parts of which should reach Severity Level 1 radioactive testing standard. Therefore, upper and lower plates cooperating with chillers acted as feeding method besides additional 2-3 times thickness;in addition, lowering sand core strength, decreasing pouring temperature and increasing dimension allowance would be adopted to avoid crack defects. Finally, the pilot impeller was cast. The results show that the casting process design is reasonable, as the liquid rises very smoothly when pouring, and no volume defects are found by means of 100% radioactive testing. Based on this casting process, 16 coolant pump impellers have been successfully produced and delivered to customers.

不同干燥方式对灵芝子实体干燥品质的影响

采用热风干燥、热泵干燥、微波热泵耦合干燥、热泵梯度升温干燥、热泵梯度降温干燥等干燥方式,探究不同干燥方式对灵芝子实体感官、营养及理化品质的影响。结果表明,微波12 min+60℃热泵干燥脱水效率最高,较单一热风干燥至少缩短180 min;微波4 min+60℃热泵干燥色泽保持相对较好;微波12 min+60℃热泵干燥粗多糖含量最高,较60℃热风干燥提高了63.26%;热泵梯度降温干燥对DPPH自由基的清除能力最强;60℃热泵干燥水溶性指数最高。从提高生产效率和营养成分保留率角度考虑,优先选择微波12 min+60℃热泵干燥方式;从产品良好色泽角度考虑,优先选择微波4 min+60℃热泵干燥方式;从产品良好功能活性角度考虑,优先选择热泵梯度降温干燥、60℃热泵干燥方式,为灵芝子实体干燥方式的选择提供理论依据。

铌对渣浆泵高铬铸铁组织和性能影响

采用对比试验,分析讨论了铌对一种渣浆泵用高铬铸铁性能的影响。分别测量了材料的力学性能、硬度和耐磨性,并对组织进行了分析。结果表明,加入铌对高铬铸铁碳化物形态有明显的改变,这种改变提高了力学性能,同时也提高了材料耐磨性。

汽车机油泵体压铸工艺数值模拟与优化

为满足汽车铝合金机油泵体压铸件高气密性和高强度的要求,解决该铸件缩松、缩孔缺陷问题,进行压铸工艺设计和优化。首先对铸件进行工艺分析,根据经验分别设计浇注排溢系统并初步选取工艺参数;再运用田口正交试验法设计了5因素4水平压铸工艺参数方案,并使用Procast进行数值模拟。将16组正交试验结果基于信噪比进行极差和方差分析,结果表明,模具温度对缩松缩孔的影响最为显著,5因素的最优工艺参数为:浇注温度650℃、模具温度240℃、慢/快压射距离200 mm/60 mm、快压射速度为3.0 m/s、慢压射速度为0.2 m/s。数值模拟结果显示,该工艺参数组合下铸件缩松、缩孔体积为1.067 cm^(3),较优化前降低了26.5%。试模结果表明,铸件外观完好,关键部位X射线探伤显示无明显缩孔;采用金相显微镜(OM)和扫描电镜(SEM)对铸件进行组织观察,发现铸件各区域组织致密;力学性能测试表明,压铸件显微硬度大于HV85,同等工艺下试棒平均拉伸强度为253.36 MPa,铸件满足使用要求。

耐酸蚀高抗磨超高铬杂质泵叶轮消失模工艺开发

从FeCr40超高铬材料的研发制备和杂质泵叶轮消失模工艺的开发两个方面进行了系统研究。首先,通过对材料性能、组织结构和化学成分的分析,优化了材料配方,显著提升了其耐酸蚀性和抗磨损性。其次,结合大口出流和均衡凝固两种理论,设计了合理的浇注系统和冒口方案,并通过工艺虚拟仿真技术验证了设计的有效性。最终,成功制备出寿命超过国外同类产品的高品质叶轮,推动了新材料在湿法冶金领域的应用。该研究不仅提高了国内杂质泵的制造水平,还打破了国外长期的技术垄断。

基于职能分工的地熊蜂飞行能力的差异分析

【目的】熊蜂是一种社会性昆虫,不同级型以及同一级型不同生理阶段具有不同的职能分工。其中,飞行能力是影响不同生理阶段熊蜂传粉和交配等职能的一个重要因素。本研究旨在探究职能分工和体重对地熊蜂Bombus terrestris飞行能力的影响,为地熊蜂的高效生产和利用提供理论依据。【方法】利用飞行磨对地熊蜂蜂王、工蜂和雄蜂3种级型以及不同生理阶段的蜂王(处女王、滞育王和产卵王)在24 h内的飞行距离、飞行速度和飞行时间等飞行能力进行测定,分析飞行能力与职能、体重、飞行后体重下降量之间的相关性。【结果】在24 h吊飞试验中,地熊蜂雄蜂的累计飞行距离、累计飞行时间、最大飞行距离和最长飞行时间均显著高于工蜂和蜂王的,雄蜂和蜂王的平均飞行速度和最大飞行速度也显著高于工蜂的,即相同条件下工蜂飞行能力最差。不同生理阶段的蜂王的飞行能力存在显著差异,处女王的累计飞行距离、累计飞行时间、最大飞行距离、最长飞行时间、平均飞行速度和最大飞行速度均显著高于滞育王和产卵王的,后二者在飞行距离和飞行速度方面无显著差异。三型蜂中,蜂王和工蜂的累计飞行距离和累计飞行时间均与体重呈显著正相关,但平均飞行速度与体重无显著相关性;雄蜂飞行能力与体重无显著相关性,但累计飞行距离和累计飞行时间与飞行后体重下降量呈显著正相关;在蜂王的不同生理阶段,处女王的累计飞行距离和累计飞行时间与体重呈显著正相关,滞育王和产卵王累计飞行距离和累计飞行时间与飞行后体重下降量呈正相关。【结论】地熊蜂飞行能力的差异与阶段性的职能改变密切相关,且不同级型和生理阶段的地熊蜂的飞行能力分别与体重和飞行后体重下降量有一定的相关性。研究结果为地熊蜂在生产中的优选优育和应用提供了一定的理论基础。

基于复杂柴油机机体特征的铸造工艺设计

为了提高V型与L型系列复杂柴油机机体柔性化制造的工艺设计效率和铸件生产质量,以典型的V型J320机体、V16机体及典型的L型K19机体、ZTD100机体为研究对象,对比研究了V型系列与L型系列复杂柴油机机体的个性特征。研究发现,两类柴油机机体在气缸排列与气缸盖数量、缸孔夹角与缸孔数量、壁连接与转角过渡等方面均有明显不同,导致工艺设计时的浇注系统类型和浇注位置放置方式等方面也存在差异。基于V型系列和L型系列复杂柴油机机体的个性化特征进行机体的铸造工艺设计,提高了机体整体铸造的工艺出品率和产品合格率。

中大型往复泵泵盖铸件的工艺设计及优化

针对中大型往复泵泵盖铸件在生产过程中出现的缩松、缩孔等缺陷,利用AnyCasting铸造模拟软件对原工艺方案进行了凝固过程的模拟以及缺陷预测。结合缩孔缩松形成机理,分析了铸件产生缺陷的原因,并对原工艺方案进行了优化。采用优化后的原工艺方案能获得质量合格的铸件,但工艺出品率仅为45%。为获得质量合格的铸件,同时提高铸件工艺出品率,设计了新的工艺方案,通过对新工艺方案的模拟优化,铸件的工艺出品率提高到62%,达到了节能减材的目的,提高了企业的生产效益。

一体压铸铝合金车身结构件的轻量化设计研究

近年大型一体压铸铝合金车身结构件逐渐被用于取代传统的冲压-焊接白车身结构。本文以一体压铸的车身后地板结构为对象,开展了轻量化设计研究。针对一体压铸车身结构件的分析问题,提出了等效分析方法;考虑压铸结构的工艺与性能,研究了结构设计中的工艺约束,阐明了其材料性能的非均质性;基于拓扑优化方法,分析了该结构的设计域,获取了最优传力路径;在上述研究内容的基础上,开展了轻量化设计,在保证性能的同时实现了7%的轻量。相关研究工作明确了新型一体压铸铝合金车身结构件的设计优化流程,具有一定的参考和借鉴意义。

乘用车车身大型压铸件设计与研究

为实现乘用车车身大型压铸件设计,从压铸工艺种类和特点出发,分析了高真空压铸在乘用车车身大型压铸件中的应用,并针对关键接头、重要梁系、主要加强件、减振器塔座、A柱模块、后地板总成、前舱总成等常见压铸件应用部位,从壁厚、加强筋和顶针布局方面分析了压铸件的设计原则和要求。

泵头体裂纹失效分析

采用化学成分分析、力学性能测试、宏观观察及金相检测等手段,对不锈钢泵头体裂纹产生的原因进行了分析。结果表明:由于泵头体抗拉强度低、晶粒稍粗,因此导致其自身的抗疲劳强度不足,在交变载荷压应力的作用下,材料因疲劳而产生裂纹。

灰铸铁水泵壳体铸件裂纹形成原因分析

汽车水泵壳体是汽车发动机冷却系统的组成部件之一,其质量对发动机冷却系统的正常运转有着重要的影响。某公司生产的汽车水泵壳体铸件材质为HT200,铸件在生产过程中出现开裂现象,为分析裂纹缺陷出现的原因,利用金相显微镜和扫描电子显微镜表征了铸件的显微组织,使用能谱分析仪、硬度计检测了铸件的物相成分和力学性能。结果表明:该裂纹形貌呈宽窄不一的折线状,裂纹断口氧化程度严重,判断为热裂纹;裂纹的形成原因是铸件的金相组织未满足设计要求,断口中S元素含量过多,存在氧化物夹渣以及铸造过程中出现应力集中区等几方面因素综合作用的结果。

大型薄壁壳体零件的消失模铸造工艺开发

通过对某拖拉机传动箱壳体结构及消失模铸造工艺性分析,设计了三种消失模铸造工艺方案,通过数值模拟分析各个方案的优劣性,对其工艺进行了优化。结合生产实际情况采用斜放式组模方案,然后进行了工艺试验,并且通过试验样件三维模型对比和加工鉴定验证了工艺方案的可行性。试验结果表明,所采用的铸造工艺方案有效地控制了铸件变形量,未见其他缺陷。

发动机缸体铸件的工艺设计及改进

设计了发动机缸体类铸件工艺方案,并利用模流分析软件分析了铸造过程中容易导致气孔、浇不足、冷隔、缩孔、缩松、错边等铸造缺陷的原因,根据分析结果对原有工艺进行针对性改进,最终使得铸件产品合格率大幅提高,并获得内部组织更加致密、外形更加美观的高品质铸件。