【作者】 邵杰；

【导师】 吴玉林；

【作者基本信息】 清华大学 ， 动力工程及工程热物理， 2009， 博士

【摘要】 微小型泵因其特殊的尺寸范围逐渐开始受到人们的关注，并显现出其良好的应用前景，特别是用于医疗设备的微小型泵，由于它可以挽救心脏病人的生命，而被众多学者大量研究。内部流动决定了微小型泵的外部性能，正确的把握泵内的流动特征是研究微小型泵流动的关键。本文以离心式血液泵的模型泵作为对象来进行泵内流动的研究，本研究也为今后更进一步的设计优化研究打下一个坚实的基础。本文采用内部流动试验和数值模拟方法来开展相关研究。搭建了适合测量泵内流动的离心式模型泵试验台，并利用折射率匹配溶液和激光诱导荧光技术对固定转速工况下泵内的流动状态进行了PIV测量，得到了测量区域的速度及相关应力的分布规律。为了得到更为完整的泵内流动信息，使用SST k-ω湍流模型和DES湍流模拟方法对泵内三维全流道进行了定常和非定常流动数值模拟得到了模型泵能量性能和内部流动的计算结果。通过对比试验结果证明非定常数值方法可以较为准确模拟泵内的流动状态。分析结果表明，小流量工况下存在“固定失速”等流动不稳定现象，而设计流量和大流量工况流动相对稳定。叶轮壁面处切应力的最大值出现在叶片头部，且叶轮壁面切应力随着流量的增大是逐渐增大的。如何在叶轮泵上产生搏动流来帮助人体健康的恢复亦成为心脏泵研究的一个热点。本文使用周期性改变叶轮转速来实现流量、扬程的搏动输出，并对此进行了试验和数值研究。试验得到了周期性变转速工况下泵的能量性能，证明模型泵在周期性变转速工况下可以产生满足设计要求的搏动流。同时，试验还得到了周期性变转速工况下四个测量点的内部流动测量结果，并分析了测量区域的应力状态。通过自编UDFs程序在Fluent程序基础上增加体积力源项和转速调整宏来完成周期性变转速工况下的泵的能量性能及内部流动数值模拟。结果显示，泵内壁面的切应力最大值的变化与转速变化一致。蜗壳和叶轮内静压的最大值的变化规律与转速的变化规律一致，但转速的变化对于吸入管内的静压没有太大的影响。更多还原

【Abstract】 Miniature pump has attracted more and more attention due to its special varyingsizes as well as its promising future for application. Particularly, the miniature pumpused for medical equipments are studied widely since its role in saving cardiac’s life.The performances of miniature pump is determined by its internal flow, therefore thekey to research on miniature pump lies in the internal flow pattern of the pump. Thisthesis focuses on the internal flow of a centrifugal model pump, which also provides afundamental work for advanced research about optimizing design in future.Both experimental measurement and numerical simulation are engaged in thiswork. A centrifugal model pump test rig is built in order to conduct PIV measurement.The test, involving the technology of index match and fluorescent, is for acquiringflow pattern in a fixed rotational speed, the velocity and stress distribution of the flowfield are thus obtained. In order to get more information about internal flow, SST k-ωturbulence model and DES method are applied to simulate3D whole passage flow.The external characteristic and internal flow pattern of the model pump are calculated.According to comparison with experimental data, the unsteady simulation is provedto be relatively accurate in predicting the flow status in the centrifugal model pump.And results show that unsteady flow phenomenon such as “stationary stall” wouldemerge at small flowrate working condition while the flow is stable in conditions ofdesigned and large flowrate working conditions. Maximum wall shear stress nearimpeller wall appears to be at the head of a blade, and the value would increase withthe rise of the pump discharge.Another hotspot in the field of blood pump research is how pulse flow could begenerated in the impeller pump to help patients in recuperation. In this thesis, amethod of changing rotational speed of impeller periodically as the pulsation workingcondition is developed to realize pulse output of both discharge and head, which isstudied through experiment and numerical computation. The performance of thepump in pulsation working condition is obtained, indicating that the model pump could produce desired pulse flow in such condition. Furthermore, flow patterns atfour testing points in pulsation working condition are achieved, in addition withanalysis of stress in testing region. After that, by adding a source term of volumeforce as well as rotational speed adjustment macro and a User Defined Functions(UDFs) program is developed based on the software FLUENT to calculate theinternal flow of the pump in pulsation working condition. Results show that changesof maximum shear stress on inner wall of a pump go with changes of speed.Moreover, the maximum value of static pressure in the volute change in a same waywith speed, but speed changes have no significant impact on the static pressure in thepump intake.更多还原