科创中国

Majority of non-Newtonian fluids are pseudoplastic with shear-thinning property,which means that the viscosity will be different in different parts of the stirred tank.In such mixing process,it is difficult to predict accurately the power consumption and mean shear rate for designing novel impeller.Metzner-Otto method is a widely accepted method to solve these questions in mixing non-Newtonian fluids.As a result,Metzner-Otto constant will become a key factor to achieve an optimum way of economical mixing.In this paper,taking glycerine and xanthan gum solutions as research system,the power consumption,stirred by the impeller composed of perturbed six-bent-bladed turbine(6PBT)with differently geometrical characteristics in a cylindrical vessel,is studied by means of computational fluid dynamics(CFD).The flow is modeled as laminar and a multiple reference frame(MRF)approach is used to solve the discretized equations of motion.In order to determine the capability of CFD to forecast the flow process,the torque test experiment is used to measure the glycerine solution power consumption.The rheological properties of the xanthan gum solutions are determined by a Brookfield rheometer.It is observed that the power consumption predicted by numerical simulation agrees well with those measured using torque experiment method in stirring glycerine solution,which validate the numerical model.Metzner-Otto constant is almost not correlated with the flow behavior index of pseudoplastic fluids.This paper establishes the complete correlations of power constant and Metzner-Otto constant with impeller geometrical characteristics through linear regression analysis,which provides the valuable instructions and references for accurately predicting the power consumption and mean shear rate of pseudoplastic fluids in laminar flow,comparatively.

Now the optimization strategies for power distribution are researched widely,and most of them are aiming to the optimal fuel economy and the driving cycle must be preknown.Thus if the actual driving condition deviates from the scheduled driving cycle,the effect of optimal results will be declined greatly.Therefore,the instantaneous optimization strategy carried out on-line is studied in this paper.The power split path and the transmission efficiency are analyzed based on a special power-split scheme and the efficiency models of the power transmitting components are established.The synthetical efficiency optimization model is established for enhancing the transmission efficiency and the fuel economy.The identification of the synthetical efficiency as the optimization objective and the constrain group are discussed emphatically.The optimization is calculated by the adaptive simulated annealing(ASA)algorithm and realized on-line by the radial basis function(RBF)-based similar models.The optimization for power distribution of the hybrid vehicle in an actual driving condition is carried out and the road test results are presented.The test results indicate that the synthetical efficiency optimization method can enhance the transmission efficiency and the fuel economy of the power-split hybrid electric vehicle(HEV)observably.Compared to the rules-based strategy the optimization strategy is optimal and achieves the approximate global optimization solution for the power distribution.The synthetical efficiency optimization solved by ASA algorithm can give attentions to both optimization quality and calculation efficiency,thus it has good application foreground for the power distribution of power-split HEV.

通过对三相异步电机功率因数控制器的工作原理分析,找出双向晶闸管的输出电压与其可控角之间的关系,提出了将功率因数控制器对晶闸管控制角控制计算转换为对时间控制的新控制算法.分析触发时间与输出电压之间的关系及触发方法,电机负载、功率因数与节能之间的关系,提出了功率因数控制器控制算法的两种控制方案,给出了控制算法程序框图,使单片机的软件设计实施方案更加方便.

针对为胶囊内窥镜供能的无线能量传输技术在应用过程中对人体组织可能造成伤害的问题,进行了无线能量传输系统发射线圈优化设计研究.分析了人体组织安全性与无线能量传输系统发射线圈之间的关系,提出用磁场均匀度、频率稳定度等指标来评价发射线圈性能,并建立了以能量传输效率为目标函数、以人体安全性和能量需求为约束条件的最优化模型.该模型可用来全面评价发射线圈性能,从而为发射线圈的设计提供依据.采用上述方法对4种类型的发射线圈进行了评价,评价结果证明了该方法的可行性.

介绍了葠窝水库发电厂旧监控系统,深入地分析了原有监控系统的现状,从设备、功能等方面剖析了其更新改造的必要性,并且从运行、维护、安全可靠及电站与调度通信等方面考虑,该厂必须进行监控系统的更新改造;在此基础上,按照"无人值班,少人值守"的设计总原则,对该电厂的保护监测系统、视频监控系统、大屏幕系统及励磁装置等设备,分别提出了具体改造方案和主要配置设备,并成功地实现了更新改造.

介绍了糯扎渡水电站厂用电备自投装置的组成、原理及备投动作方案,对备自投动作方式存在的动作逻辑缺陷进行了分析,并提出了改进方法,经现场模拟,改进后的备自投能够正确动作.

南水北调中线潴龙河倒虹吸涵管基础处理,采取振冲碎石桩施工工艺,选择适宜的振冲器是振冲碎石桩施工成功的关键,本工程采取ZCQ165、ZCQ130组合振冲器,克服了厚卵石层地质振冲碎石桩施工难题,取得了良好的效果,可为类似工程施工提供借鉴.