人造心脏泵及心脏瓣膜泵研究

自1995年以来,江苏大学医学工程所先后研制四种不同设计及用途的心脏泵及心脏瓣膜泵,分别在美国德州大学医学院及镇江市第一人民医院先后用于动物试验.最近研制的江大Ⅳ号泵是心室内辅助泵,用于急性病人的抢救.     

Estimation of endotoxin inhalation from shower and humidifier exposure reveals potential risk to human health

This paper investigates potential exposure to endotoxin in drinking water through the inhalation of aerosols generated by showers and humidifiers. Adverse health effects attributable to the inhalation of airborne endotoxin in various occupational settings are summarized, as are controlled laboratory inhalation studies. Data from investigations estimating aerosolization of particulate matter by showers and humidifiers provide a basis for similar analyses with endotoxin, which like minerals in water, is nonvolatile. A theoretical assessment of the inhalation of aerosolized endotoxin showed that while the likelihood of an acute response while showering is minimal, the same is not true for humidifiers. Ultrasonic and impeller (cool mist) humidifiers efficiently produce large numbers of respirable particles. It is predicted that airway inflammation can occur if humidifier reservoirs are filled with tap water, sometimes even at typical drinking-water distribution-system endotoxin concentrations. Higher endotoxin levels occasionally found in drinking water (>1,000 EU/ml) are very likely to induce symptoms such as chills and fever if used as humidifier feed water. While it is unlikely that treated drinking water would contain extremely high endotoxin levels occasionally observed in cyanobacterial blooms (>35,000 EU/ml), the potential for serious acute health consequences exist if used in humidifiers.     

混流式血泵的数值模拟及性能分析

轴流式血泵转速过高、离心式血泵容易产生流动死区是造成血液损伤的重要原因,而混流式血泵能有效缓解轴流式血泵的转速过高以及离心式血泵的流动死区问题。基于此,本研究旨在探究闭式叶轮混流式血泵的性能效果。通过数值模拟的方法对闭式叶轮混流式血泵进行数值模拟,分析该类型血泵的流场特性及压力分布情况,探讨其水力性能以及可能对红细胞造成的损伤程度,并与半开式叶轮结构混流式血泵的数值模拟结果进行性能对比。结果表明:本研究中的闭式叶轮混流式血泵具有良好的性能,能够安全高效运行。该泵在5 L/min下能够达到100 mm Hg的扬程,血泵内流动均匀,没有明显的涡流、回流以及流动停滞现象,压力分布均匀合理,可有效地避免血栓;溶血指数平均值(HI)为4.99×10^-4,具有良好的血液相容性;与半开式叶轮混流式血泵相比,闭式叶轮混流式血泵扬程和效率更高、溶血指数平均值更小,且具有更好的水力性能及避免血液损伤的能力。通过本文研究结果,或能为闭式叶轮混流式血泵的性能评价提供依据。     

New Mechanism to Reduce the Size of the Monopivot Magnetic Suspension Blood Pump: Direct Drive Mechanism

Abstract: Size reduction of the monopivot magnetic suspension blood pump has been achieved by reducing the size of the magnetic suspension and employing a direct drive mechanism in place of a brushless DC motor and a magnetic coupling. The flow has also been improved using a closed hollow impeller to remove flow obstruction at the inlet and using radial straight vanes to reduce the impeller speed by 30%. Hemolysis testing was conducted for the new models. Results showed that model DD1 presented only a slightly higher level of hemolysis than a regular extracorporeal centrifugal pump.     

Implantable centrifugal blood pump with dual impeller and double pivot bearing system: electromechanical actuator, prototyping, and anatomical studies

An implantable centrifugal blood pump has been developed with original features for a left ventricular assist device. This pump is part of a multicenter and international study with the objective to offer simple, affordable, and reliable devices to developing countries. Previous computational fluid dynamics investigations and wear evaluation in bearing system were performed followed by prototyping and in vitro tests. In addition, previous blood tests for assessment of normalized index of hemolysis show results of 0.0054 ± 2.46 × 10^?3 mg/100 L. An electromechanical actuator was tested in order to define the best motor topology and controller configuration. Three different topologies of brushless direct current motor (BLDCM) were analyzed. An electronic driver was tested in different situations, and the BLDCM had its mechanical properties tested in a dynamometer. Prior to evaluation of performance during in vivo animal studies, anatomical studies were necessary to achieve the best configuration and cannulation for left ventricular assistance. The results were considered satisfactory, and the next step is to test the performance of the device in vivo.     

基于激光三维扫描技术的微型轴流血泵叶轮加工精度检测

目的检测微型轴流血泵的转子叶轮加工精度,建立叶轮形状复杂的微型血泵叶轮加工精度检测方法。方法本文采用激光三维扫描技术获得FW-2型轴流血泵叶轮的点云,利用逆向工程软件Geomagic Studio对点云进行处理后建立三维模型。将建立的叶轮模型与设计的叶轮模型导人Geomagic Qualify软件进行对比,即可分析具有复杂曲面的FW-2型轴流血泵转子叶轮各个型面的加工精度。结果对比激光扫描得到的叶轮模型与设计的叶轮模型,结果显示FW-2型轴流血泵转子叶轮整体加工精度符合要求,只有极小区域加工精度较低。结论激光三维扫描结合逆向三维建模技术是微型血泵复杂叶轮的加工精度检测的有效方法。本研究为微型血泵叶轮检测提供了一种新思路, 对确定血泵使用过程中的血栓形成原因,改进血泵设计具有重要意义。     

工业结晶器内流体流动过程的数值模拟

对某无机盐工业结晶反应器中的流体流动过程进行了三维数值模拟,采用多重参考系法(MRF)及标准k-ε模型,分析了桨型、转速、桨的安装高度对结晶器流场的影响情况。计算结果表明：速度分布主要集中于内导流筒内部以及内、外导流筒之间的区域,相应地,结晶器被粗略地划分为对反应结晶过程具有不同作用的两个区域——内导流筒内速度较大的循环区和外导流筒外速度较小的沉降区。通过对循环区和沉降区的速度分布比较,认为推进式搅拌桨的流体流场速度云分布均一性要好于其他型式的搅拌桨,其最佳安装高度为3.5～5.7 m。在合适的搅拌速率下,结晶器沉降区的流体流动速率具有均匀向上的特点,可以有效带出部分小粒子,有利于获得大粒度产品。通过流动过程的数值模拟获得详细的流场分布及操作参数,为结晶器结构和操作参数优化提供了理论指导。实践表明：优化后的产品粒度显著提高,产品中大于0.2 mm的粒子从优化前的不足50%提高到优化后的90%以上,干燥产品的天然气消耗从优化前的22 m3/t降低到优化后的15 m3/t,节能降耗效果显著.     

Manufacturing of Closed Impeller for Mechanically Pump Fluid Loop Systems Using Selective Laser Melting Additive Manufacturing Technology

In the space industry, the market demand for high-pressure mechanically pumped fluid loop (MPFL) systems has increased the interest for integrating advanced technologies in the manufacturing process of critical components with complex geometries. The conventional manufacturing process of a closed impeller encounters different technical challenges, but using additive manufacturing (AM) technology, the small component is printed, fulfilling the quality requirements. This paper presents the Laser Powder Bed Fusion (LPBF) process of a closed impeller designed for a centrifugal pump integrated in an MPFL system with the objective of defining a complete manufacturing process. A set of three closed impellers was manufactured, and each closed impeller was subjected to dimensional accuracy analysis, before and after applying an iterative finishing process for the internal surface area. One of the impellers was validated through non-destructive testing (NDT) activities, and finally, a preliminary balancing was performed for the G2.5 class. The process setup (building orientation and support structure) defined in the current study for a pre-existing geometry of the closed impeller takes full advantages of LPBF technology and represents an important step in the development of complex structural components, increasing the technological readiness level of the AM process for space applications.     

出口角对离心泵内固液两相流动影响

采用欧拉多相流模型、标准k-ε湍流模型与SIMPLEC算法,应用计算流体力学软件Fluent,对3台不同叶片出口安放角的离心泵内的固液两相湍流进行了数值模拟,分析了叶片出口安放角对泵内部固液两相流场的影响.计算结果表明:在叶轮流道内,固体颗粒的相对运动方向比液相更偏向叶片压力面,大叶片出口角叶轮内两相速度的夹角较大.通过对比不同叶轮内压力分布及固体颗粒体积浓度分布,得出以下结论:大出口安放角的叶轮压力面附近聚集了更多的颗粒,导致大量颗粒与叶片尾部的压力面相撞;叶片出口安放角增大使得叶轮出口压力增大.     

离心式血泵优化设计研究进展

人工心脏（血泵）应兼具优良的水力学性能和血液相容性,血泵性能的提升依赖于良好的优化设计方法。本文对近年离心式血泵优化设计相关的工作进行总结,首先回顾数值模拟方法的进展,高保真度的流场数值模拟是进行血泵优化设计的先决条件;接着主要从叶轮、蜗壳、间隙等方面概括优化设计的参数敏感性研究;总结优化设计常用的几种方法,包括参数敏感性研究、正交优化、机器学习/遗传算法、拓扑优化;最后提出血泵优化设计的展望及存在的挑战。研究结果可为未来的血泵优化设计工作提供有益的借鉴和参考。