Development and Application of a Shaft-type Tubular Pumping System with a Siphon Discharge Passage

Based on the characteristics of large flow rate , low head , short annual operation time , and high reliability of the city flood-control pumping stations , a new-type shaft tubular pumping system featuring a shaft suction box and a siphon-type discharge passage with a vacuum breaker as the cutoff device was developed , which possesses such advantages as simple structure , reliable cutoff , and high energy performance.Taking some pumping stations as the case studies , in the light of the specified operation conditions , the hydraulic optimal design of the shaft-type tubular pumping system was determined and the optimized shape of the system was recommended.The performance prediction based on the computational fluid dynamics methodology was determined and the model test verification was conducted.The results show that the predicted data agree with the experimental head and efficiency so that both methods can be used to determine the performance of a real pumping station.Finally , the in-situ measurements of a pumping station during the commissioning period further verified that the shaft-type tubular pumping station with a siphon discharge passage is of higher efficiency , more reliable and stable.

Principle and Experimental Verification of Caudal-fin-type Piezoelectric-stack Pump with Variable-cross-section Oscillating Vibrator

In the traditional flow-resistance-differential (FRD) type valve-less piezoelectric pump, the generated outflow and pressure are discontinuous because of the inherent periodicity and fluctuation of the pump. To overcome these drawbacks, utilizing the bending vibration of piezoelectric bimorph to drive fluid was conducted. However, our investigation on the current status of this piezoelectric bimorph pump shows that larger driving force and vibration amplitude are required for fluid pumping; the pumping can be realized through the centrifugal force; and the mechanism of fluid pumping is no longer further studied. Based on these cases, the paper designed a piezoelectric-stack pump with variable-cross-section oscillating (VCSO) vibrator by imitating the swing of the caudal-fin of tuna, and the pump is neither the rotating type nor the volumetric type according to the taxonomy. The interaction between the oscillating vibrator and the fluid parcel is firstly analyzed from the viewpoint of momentum conservation, and the analytical expression of pump flow rate is obtained. Then the modal and harmonic response analyses on the vibrator immerged in water are carried out. From the analyses the first two orders resonance frequencies are 832 Hz and 1 939 Hz, respectively, and the peak value of the tip amplitude is 0.6 mm. Laser Doppler vibrometer is used to measure both the frequency and vibration amplitude, and the determined first two orders resonance frequencies are 617 Hz and 1 356 Hz, respectively. The measured tip amplitude reaches to the peak value of 0.3 mm. At last, experimental measurement for the flow rates with different driving frequencies is conducted. The results show that the flow rate can reach 560 mL/min at 1 370 Hz when the pump runs under the backpressure of 30 mm water column. And the flow rate is as much as 560% of that of experiment results carried out by researchers from Brazil. The proposed pump innovates in both theory and taxonomy; in addition, the pump overcomes the drawbacks such as large flow fluctuation and low flow rate in the traditional FRD type pumps, which will help to broaden the application of the valve-less piezoelectric pump.

Continuous Reaction Crystallization of Struvite in a DTM Type Crystallizer With Jet Pump of Ascending Suspension Flow in a Mixing Chamber–Kinetic Approach of the Process

Reaction crystallization of struvite in water solutions containing 0.20 mass % of phosphate(V) ions by magnesium and ammonium ions addition was investigated experimentally. Process was carried out in DTM type crystallizer with liquid jet pump device in 298 K assuming stoichiometric conditions. Struvite crystals of mean size Lm 5.2-23.0 μm were produced depending on pH (9-11) and mean residence time of suspension in a crystallizer τ (900-3600 s). Under these conditions linear growth rate of struvite crystals (SIG MSMPR kinetic model) decreased 2-time with the increase in pH and 3-time with the elongation of mean residence time of crystal suspension from 7.11×10-9 m/s (pH 9, τ900 s) to 1.65×10-9 m/s (pH 11, τ3600 s). Nucleation rate varied within the 7.9×108-1.8×1010 1/(sm3) limits. Struvite product of maximal linear size exceeded 100 μm with 10 vol. % of < 3 μm fraction corresponded to pH 9 and τ3600 s.

Fabrication of 16W all-normal-dispersion mode-locked Yb-doped rod-type fiber laser with large-mode area

A mode-locked ytterbium-doped rod-type fiber laser with 85 ~tm core diameter is developed based on the nonlinear polarization evolution in an all-normal-dispersion ring cavity, in which a uniaxial birefringent plate is used as the spectral filter. Average power up to 16 W is obtained at the repetition rate of 58 MHz, and the pulse duration is compressed to 182 fs with a grating-pair compressor. The output laser pulses show very good beam quality and power stability.

胰岛素泵短期强化治疗2型糖尿病的疗效及影响因素分析

目的:观察胰岛素泵持续皮下胰岛素输注(continuous subcataneous insulin infusion,CSII)短期强化治疗2型糖尿病(T2DM)患者的真实世界疗效并探讨疗效关联的影响因素。方法:对本院收治住院治疗的369例T2DM患者开展CSII短期强化治疗,依据治疗第5天的血糖水平,分组为血糖控制达标组和血糖控制不达标组。比较两组患者的糖代谢、生理、生化等方面指标的差异,采用回归统计方法,分析胰岛素泵疗效的影响因素。结果:经过4 d CSII短期治疗,225例(61%)患者血糖控制达标,144例(39%)血糖控制未达标。与达标组相比,未达标组年龄更大,每千克体重每日胰岛素总剂量(TDD)、空腹血糖(FBG)、空腹胰岛素、空腹C肽、胰岛素抵抗指数(HOMA-IR)水平更高,而血磷、胰岛素生长因子1(IGF1)水平则是显著低于达标组。生化指标方面,两组在血脂水平、肝功能、肾功能整体上无显著差异。单因素回归及多因素逐步回归分析结果表明,餐后2 h胰岛素、TDD、血磷是胰岛素泵疗效的关键影响因素。其中,血糖控制达标与血磷呈正相关,与餐后2 h胰岛素、TDD呈负相关。结论:使用胰岛素泵持续皮下输注胰岛素是短期强化治疗T2DM的理想方法,为了获得更满意的血糖控制达标率,临床使用时应更加关注患者的血磷、餐后2 h胰岛素指标水平及TDD。

Verification of VVER-1200 NPP Simulator in Normal Operation and Reactor Coolant Pump Coast-Down Transient

Verification of operation parameters of VVER-1200 NPP Simulator installed at Nuclear Training Center, VINATOM has been performed. This simulator has been supplied for Vietnam in the framework of IAEA TC Project VIE2010 on Developing Nuclear Power Infrastructure—Phase II hosted by the Vietnam Atomic Energy Agency (VAEA). The comparison of the main parameters in nominal power operation with design data given in safety analysis report of VVER-1200/V392M as well as Ninh Thuan FSSAR is presented. In this study, the reactor coolant coast-down transient is investigated using the VVER-1200 NPP simulator. The simulated results performed in the simulator through switching off one reactor coolant pump in comparisons with experiment results performed in VVER-1000 reactor are given. The similarity between the measured and simulated results shows that the thermal hydraulic characteristics and the control protection systems are modeled in a reasonable way. A good agreement in operating parameters was found between the VVER-1200 NPP simulator and VVER-1200/V392M’s PSAR.

Performances and Rotating Flows of Rotary Jet Pump

The rotary jet pumps, namely the pitot pumps, are composed of the rotating casing with the impeller channels and the stationary pick-up tube for discharging, are known as the one of high pressure pumps in the U.S. market. The pumps, however, have been prepared experientially, because of poor knowledge for the flow conditions and the pump performances. Then, this paper discusses the pump performances and the internal flow conditions in the rotating casing. Three types of the pick-up tube were prepared for the experiments to know the pump performances and the flow conditions in the rotating casing. The flow in the rotating casing is nearly in the forced vortex type and gives the higher pressure at the pick-up tube inlet. The more cross-sectional area of the pick-up tube channel is large, the more head and discharge are higher with excellent efficiency. Moreover, the authors confirmed that the secondary flow runs toward the rotating center at the wake flow region behind the pick-up tube.

超声左心室自动功能成像评估胰岛素泵输注治疗2型糖尿病合并肺结核左心室功能

目的:探索超声左心室自动功能成像(AFI)评估胰岛素泵输注治疗2型糖尿病(T2DM)合并肺结核左心室功能的效果。方法:选取2020年12月至2022年10月新疆医科大学第一附属医院收治的108例T2DM合并肺结核老年患者纳入观察组,选取同期在本院接受体检的90名健康体检者纳入健康对照组。观察组接受胰岛素泵的输注治疗,并于治疗前后采用超声左心室AFI评估左心室功能参数;健康对照组检查左心室指标及血糖指标。对比两组的临床指标以及超声参数上的差异性。结果:观察组治疗后与治疗前比较收缩压与空腹血糖水平均较低;观察组治疗后与治疗前分别与健康对照组相比长轴方向的全球纵向应变(GLPS-LAX)、四腔心切面的全球纵向应变(GLPS-A4C)及平均全球纵向应变(GLPS-AVG)比较均有所降低;观察组治疗后与治疗前相比GLPS-LAX、GLPS-AVG较高,差异有统计学意义(t=2.846、4.926,P<0.05)。结论:T2DM合并肺结核患者在经过胰岛素泵注射治疗后,通过采用超声左心室AFI对患者的左心室功能进行评估时发现,其左心室功能获得有效改善,采用超声左心室AFI评估T2DM合并肺结核左心室功能具有重要的临床意义。

物料转运设备闭式泵控多马达行走液压系统

某生产线超大超重物料在生产转运过程中工况要求非常高,特别是要求行走驱动系统稳定可靠且能耗低装机功率小。通过对比分析传统常用的比例阀控马达同步行走液压系统和闭式泵控多马达行走液压系统原理和技术特点,最终以闭式泵控多马达行走液压系统作为生产线试验台实验对象,对其加载和停止过程中马达进出油口压力进行了试验研究,为未来闭式泵控多马达行走液压系统在重载转运设备的批量生产使用提供指导。

利拉鲁肽序贯联合胰岛素泵强化治疗对初诊肥胖T2DM疗效及对患者相关指标的影响

目的探讨利拉鲁肽序贯联合胰岛素泵强化(CSⅡ)治疗初诊肥胖2型糖尿病(T2DM)疗效及对患者糖脂代谢、胰岛功能及体重相关指标的影响。方法选取我院内分泌科于2018年4月-2022年4月收治的合并肥胖[体重质量指数(BMI)≥28 kg/m 2]的T2DM患者104例,均空腹血糖(FPG)≥11.1 mmol/L和(或)糖化血红蛋白(HbA1c)≥9%,将患者分为常规组与GLP-1组,每组52例。两组均给予胰岛素泵强化治疗1周,血糖控制达标,撤泵后常规组给予二甲双胍,GLP-1组给予利拉鲁肽注射治疗,两组患者治疗10周。比较两组患者治疗前后体重相关指标(BMI、腰围)、糖代谢[FPG、餐后2 h血糖(2 hPG)及HbA1c]、脂代谢[载脂蛋白A1(ApoA1)、载脂蛋白B(ApoB)、总胆固醇(TC)及三酰甘油(TG)]、胰岛素抵抗情况[胰岛β细胞指数(HOMA-β)、胰岛素抵抗指数(HOMA-IR)]并统计药物不良反应。结果治疗后,两组患者BMI、腰围、FPG、2 hPG及HbA1c、ApoB、TC、TG及HOMA-IR均显著下降(P<0.05),且GLP-1组显著低于常规组(P<0.05);治疗后,两组患者ApoA1、HOMA-β均显著上升(P<0.05);GLP-1组与常规组总药物不良反应发生率差异无统计学意义(P>0.05)。结论利拉鲁肽序贯联合CSⅡ治疗可显著改善肥胖T2DM患者体脂情况、糖脂代谢以及胰岛素抵抗等情况,不良反应较小,安全有效,值得推广应用。

基于曲率控制前缘的离心泵压力脉动及水力性能分析

蜗壳式离心泵作为流体输送的核心设备,压力脉动及水利性能对泵的稳定性、噪声、寿命等有重大影响。结合曲率控制前缘的设计方法,按增长率1.19%、0.47%、0.32%设计,建立前缘轴长比为0.96、2.11、3.11、4.11的蜗壳式离心泵,以SSTκ-ω模型定常计算结果为初始条件,进行κ-εRNG模型非定常分析,通过频域图分析蜗壳式离心泵压力脉动,并通过矢量云图分析水力性能。结果表明:设计的模型最佳流量为35 m 3/h,设计效率与模拟效率误差仅为2%;前缘轴长比不同,流道内压力扩散有差异;前缘轴长比为3.11时出口压力脉动偏低,低频区更易产生压力脉动;前缘轴长比为0.96时,压力脉动范围偏小,适用于一定流量范围内扬程变化较大的工况。

核主泵用机械密封摩擦学性能研究进展

核主泵是核电厂的核心元件,核主泵机械密封在其中起到防止介质泄漏的作用。当前,我国核主泵密封装置相关技术和产品受到国外垄断限制,核主泵摩擦副在运行状态下泄漏严重破坏核电系统的稳定运行和长周期服役,其摩擦学性能直接影响核主泵的运行性能。对于动压式核主泵机械密封,若没有处于完全液膜润滑状态,密封装置会出现异常磨损和泄漏率增大导致核主泵故障。针对核主泵摩擦副的液膜特性,从数学模型计算和软件仿真两方面分析。对温度场、速度场和应力场等进行分析,总结了密封环及副密封材料、端面热变形对摩擦学性能的影响,概述了端面形状的动压润滑机理及波度面、槽型结构和加工方法等因素对摩擦磨损的影响,为核主泵密封性能的提高和可靠运行提供理论基础。

叶顶间隙对蜗壳式混流泵流动特性影响研究

采用计算流体力学(CFD)数值模拟技术,研究了蜗壳式混流泵在不同叶顶间隙下的水力性能及内部流动特性。通过对流场、涡流和压力分布的分析,揭示了叶顶间隙变化对泵装置扬程、效率及运行稳定性的影响。结果表明,随着间隙尺寸的增大,混流泵的整体效率逐渐下降,且对大流量工况的影响尤为显著。同时,叶顶间隙的增大会导致叶轮区域泄漏涡的增强,影响泵的运行稳定性。

胰岛素不同注射方式对糖尿病血糖控制效果的影响研究

目的分析胰岛素不同注射方式对2型糖尿病患者血糖控制情况的影响。方法选取2021年9月—2023年9月安溪县医院收治的186例2型糖尿病患者为研究对象,利用最新统计学软件生成随机序列后将其分为对照组、观察组,各93例。两组研究对象均选用门冬胰岛素治疗,其中对照组注射方式为多次胰岛素皮下注射,观察组注射方式为胰岛素泵持续泵注。对比两组血糖控制情况、胰岛素使用剂量、血糖达标情况以及胰岛β细胞功能。结果观察组空腹血糖、餐后2 h血糖及糖化血红蛋白水平均低于对照组,差异有统计学意义(P均<0.05)。观察组平均每天胰岛素使用量低于对照组,血糖达标时间短于对照组,且在达标即刻使用的胰岛素总量少于对照组,差异有统计学意义(P均<0.05)。观察组胰岛β细胞功能优于对照组,差异有统计学意义(P<0.05)。结论对于2型糖尿病患者,采用胰岛素泵持续泵注这一注射方式,有利于改善血糖、血压及血脂水平,同时改善胰岛β细胞功能,且使用胰岛素剂量更低,能够更快速地达到控糖标准。

T2DM合并冠心病介入治疗术后患者应用胰岛素泵强化降糖疗法的作用价值

目的探究胰岛素泵强化降糖疗法应用于2型糖尿病(type 2 diabetes mellitus,T2DM)合并冠状动脉粥样硬化性心脏病(简称冠心病)介入治疗术后的效果。方法回顾性选取2023年1—12月在四川大学华西厦门医院(研究院)就诊的130例T2DM合并冠心病患者的临床资料,全部患者均选择冠心病介入术治疗,按照术后选用的降糖疗法不同分为对照组(常规胰岛素注射)和研究组(胰岛素泵强化降糖),各65例。比较两组血脂及血糖水平(糖化血红蛋白、餐后2 h血糖、空腹血糖、总胆固醇、甘油三酯)、胰岛功能(胰岛β细胞功能指数、胰岛素抵抗指数)情况。结果治疗前两组血糖、血脂及胰岛功能对比,差异无统计学意义(P均>0.05)。治疗2周后,研究组血糖及血脂指标均低于对照组,差异有统计学意义(P均<0.05)。治疗2周后,与对照组比较,研究组胰岛β细胞功能指数更高,胰岛素抵抗指数更低,差异有统计学意义(P均<0.05)。结论接受介入术的T2DM合并冠心病患者术后降糖中选择胰岛素泵,能够改善患者血脂及血糖水平,提高胰岛功能。

大流量、高扬程、超大轴径泥泵机械密封的研制及优化

“天鲲号”的投产使用,极大地提高了疏浚工程的施工效率,但目前“天鲲号”泥泵采用的L型橡胶密封在高排压下很快磨损失效引起泄漏停机,严重影响施工进度。针对这一问题,提出采用机械密封代替L型橡胶密封的方法。通过技术参数计算,对密封部位进行仿真,对机械密封进行设计、制造,并通过2次实船测试对机械密封的性能开展验证。研究结果为解决疏浚装备泥泵密封在大流量、高扬程、超大轴径及高压下寿命短的问题提供了一种新的方案。

轴流泵式混合室内水力学特征的数值模拟

混合澄清槽是重要的萃取分离设备,采用计算流体力学(CFD)方法研究了一种新型轴流泵式混合澄清槽内流体流动与剪切力,确定了搅拌桨型对混合室内的平均剪切速率、剪切速率空间分布、剪切速率概率分布的影响,结果表明:与传统泵轮式混合室相比,轴流泵式混合室内锥形泵及双桨叶的搭配可以大幅提高混合室的抽吸力与剪切力,搭配六叶半闭式涡轮桨后抽吸力可提升87%,混合室平均剪切速率提升90%,同时轴流泵式混合室内剪切力的分布更加均匀。

补气增焓热泵技术的研究现状及展望

补气增焓热泵(VIHP)技术因在低温工况下具有高效、节能、环保等优势,成为近年来能源领域内的研究热点之一。阐述了现有文献中关于VIHP技术的研究现状,分别从应用型式、压缩机型式及其实现方法和优化研究进展等方面进行了深入讨论,对比分析了相关研究结果提升VIHP系统性能的优势和不足。并结合研究中存在的问题对其发展趋势进行展望,为VIHP技术未来的研究应用提供参考。

热泵型多联式空调系统稳态仿真

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