基于人工神经网络的固相质量流量软测量研究

采用弯管法测量稀相气固两相流中固相质量流量时,固相流量与其影响因素（压差、流量系数、气固混合密度等）之间存在着复杂的非线性关系,给粉体的精确测量带来困难。利用人工神经网络优良的非线性映射能力,建立了一个基于BP网络固相质量流量软测量模型,并以实验数据为样本对网络进行训练,实现对固相质量流量的在线估计,与实验结果吻合较好,为稀相气力输送中固相质量流量在线测量提供了一种简单、可靠的新方法。     

气固两相流固体质量流量测量技术

依据测量原理,对气固两相流固体质量流量测量方法进行了分类,重点介绍当前国内外常用或研究较为热门的几种测量方法和它们所涉及到的相关技术,简单分析了其今后的发展方向.     

基于径向基函数网络的煤粉质量流量测量

为了提高工业生产中煤粉质量流量检测的测量精度,在双弯管法测量固相质量流量原理的基础上,利用人工神经网络优良的非线性映射能力,将固相质量流量难以确定的影响因素反映到网络的连接权值中,建立基于径向基函数网络的软测量模型;在气力输送煤粉实验平台上进行实验,获取实验数据,以实验数据为样本对模型进行训练与仿真。结果表明,模型测量误差不超过3%,是煤粉固相质量流量测量的一种简单、有效的方法。     

弯管流量计压强特性及流量系数的研究

针对4种不同管径、3种不同弯径比的90°圆形弯管流量计的压强场进行了数值模拟和试验研究.研究了弯管径向的压强分布,弯管内外壁压强沿程分布,弯径比对压强的影响,测量流量的最佳断面,以及不同弯径比和不同管径情况下的流量系数.得出了弯管流量计流量系数和最佳测量断面的选择方法.     

利用弯管测量流量的理论与实践

文章分析了流体在弯管内的流动特性，从理论上推导出流经弯管的流体流量与压差的关系的基本公式。利用PHOENICS软件对弯管内流体的流动速度、压力分布进行了计算，得出了流量与弯管内最大压差的关系与实验一致的结果，分析了弯管流量系数与弯管结构参数的关系。     

利用弯管测量流量的理论分析与实验研究

本文分析了流体在弯管内的流动特性，导出流经弯管的流体流量与压差关系的基本公式。利用PHOENICS软件对弯管内流体的流束和压力分布进行了模拟计算，得出了流量与弯管内最大压差的关系与实验一致的结果及弯管流量系数与弯管结构参数的关系。     

湿度在弯管流量计测量流量时的影响分析

弯管流量计测量湿气体流量时,气体的相对湿度随着温度、压力的变化而变化,如采用固定湿度补偿,测量结果与真实值比会有较大误差.本文依据现场实例,结合弯管流量计测量过程,进行了详细的分析和说明.     

弯管内流体流动的模拟计算与实验研究

通过对弯管内流体流动进行数值模拟计算，分析弯管内流体流动的特性。实验研究表明，流经弯管的流量Q与弯管的内外侧压差Ap的函数、（2△p/ρ）平方根之间有较好的线性关系，以及当弯管结构参数在适当范围内变化时，其流量系数变化不大，近似为一常数。弯管作为管道流量的检测元件对直管段无严格的要求，在不同的直管段条件下，流量Q与压差△ρ的函数、（2△p/ρ）平方根之间几乎保持同样的线性关系。     

弯管流量计的研究

介绍了弯管流量计的理论和实验研究 ,给出了研究结论 ,并指出了达到 1 0级测量准确度的弯管流量计规模化生产的条件     

新型气固两相流亚微米级粉体浓度及浓度分布测量方法

提出了一种新型的基于激光散射原理的气固两相流亚微米级粉体浓度及浓度分布测量方法, 适合流场的物质组成及其浓度分布等气固两相流特性分析。以烟气烟尘浓度检测为例, 介绍了基于上述测量原理的烟尘浓度监测装置的设计及其工程实现方法, 可望推广到石油、医药等其它化学工业的气固两相流浓度分析。     

电容层析成像技术测量煤粉输送浓度的研究

采用电容层析成像技术,对常温下稀疏气力输送的煤粉浓度进行了测试研究。为了利用电容传感器敏感场的分布特性,实验系统中设置了一旋风分离装置,通过旋风分离作用将煤粉颗粒集中在壁面区域,传感器电极布置在分离器直管上。改变螺杆给粉速度以及风量可改变煤粉输送浓度,通过对管道截面体积浓度、波动特性以及体积浓度平均测量结果的对比分析,表明利用该方法测量煤粉输送浓度结果准确、可靠。     

燃油流量高精度计量的研究

分析了涡轮流量传感器的工作原理。研究了由于燃油的温度变化引起的传感器本身尺寸变化、燃油密度变化给计量精度带来的影响。在温度、压力可调整的燃油实验装置上对传感器进行了实验研究。发现可以用线性公式来描述质量仪表系数随温度变化的规律；质量仪表系数的绝对变化量、相对变化量可近似为恒定值。提出了两种温度补偿方法，可分别得到优于0．2％和优于0．25％的质量流量计量精度。     

静电传感器空间灵敏度特性研究

对应用于气-固两相流参数检测的静电传感器的空间灵敏度分布特性进行了研究。建立了静电传感器的数学模型,并应用大型有限元分析软件ANSYS对不同的传感器结构尺寸内的静电场分布进行了数值分析,进而获得了静电传感器空间灵敏场分布。结果表明：静电传感器的灵敏场分布不均匀,在不同的轴向和径向位置灵敏度不同,壁面附近灵敏度较高,轴线处较低;轴向长度越长,灵敏度越高,灵敏场相对越均匀;由于边缘效应,静电传感器的灵敏空间略大于其几何结构所确定的空间。     

旋风分离器两相流研究综述

综述了旋风分离器内部流场、颗粒运动和数值计算模型的理论研究发展历程。     

浓度对超声检测颗粒两相流的影响

讨论了颗粒两相流检测中常用的超声单散射模型和复散射模型 ,研究了浓度对超声检测颗粒两相流的影响。通过实验测得了超声在体积浓度为１ %～１０ %的ＴｉＯ２-水悬浊液中传播时的衰减系数。结果表明 ,悬浊液中的超声衰减系数随着浓度和频率的升高而增大。实验的结果和使用的超声散射模型的理论值在低浓度时吻合较好 ,而在高浓度时有所偏离。文中对这种偏差的原因进行了讨论。     

液固两相流超声断面成像装置的研究

以水、泥沙构成的液固两相流为研究对象,制作了压电超声传感器、传感器阵列及超声波收发电路,构成了两相流断面超声投影数据采集系统,实现了计算机高速数据采集。实验验证,设计的压电传感器谐振频率达到200 kHz,发射角度大,接收灵敏度高;采用RC滤波方法,能够有效地滤除接收传感器受到的工频电磁干扰信号;收发传感器交替排列的传感阵列既可以获得最大数量的投影数据,又可以使强弱电电路分离,免受互扰;采集的投影数据能够反映固相流动状况。     

Fundamental Mass Flow Measurement of Solid Particles

A generic mass flow measurement device was developed as a variation on the theme of counting. In a hypothetical infinitely sparse mass flow, the number of passing particles could be counted in a time frame and multiplied by the mean mass per particle to obtain a mass flow per time unit. In a mass flow of realistic density, however, particles travel in cluster formation and direct counting of individual particles is impossible. If a method could be available that reconstructs the original number of particles in a cluster, the mass flow can be computed for realistic clustered mass flows. This reconstruction algorithm was developed in this research; it uses the measured cluster lengths to reconstruct the total number of particles in each passing cluster. The lengths of the clusters were measured with an optoelectronic device. The reconstruction algorithm was developed using simulation, augmented by clustering theory. For identical diameter particle flow, simulation results showed that the number of particles in a cluster could be reconstructed using a very simple reconstruction formula. This formula uses only the total number of clusters per time frame and the total number of individual particles measured in the same time frame. However, identical diameter flow is not realistic, since even identical particles are measured with a certain error. Reconstruction of the realistic distributed diameter particle flow was approximated using the identical particle method. The optical mass flow sensor has major advantages over traditional methods. It is virtually insensitive to vibrations, contamination, temperature drift, and misalignment and the underlying measurement concept is well understood. But most importantly, the sensor does not require calibration. The mass flow of identical particles (4.5 mm air gun pellets) was measured with an error smaller than 3% even for high density flow rates.     

Fundamental Mass Flow Measurement of Solid Particles

A generic mass flow measurement device was developed as a variation on the theme of counting. In a hypothetical infinitely sparse mass flow, the number of passing particles could be counted in a time frame and multiplied by the mean mass per particle to obtain a mass flow per time unit. In a mass flow of realistic density, however, particles travel in cluster formation and direct counting of individual particles is impossible. If a method could be available that reconstructs the original number of particles in a cluster, the mass flow can be computed for realistic clustered mass flows. This reconstruction algorithm was developed in this research; it uses the measured cluster lengths to reconstruct the total number of particles in each passing cluster. The lengths of the clusters were measured with an optoelectronic device. The reconstruction algorithm was developed using simulation, augmented by clustering theory. For identical diameter particle flow, simulation results showed that the number of particles in a cluster could be reconstructed using a very simple reconstruction formula. This formula uses only the total number of clusters per time frame and the total number of individual particles measured in the same time frame. However, identical diameter flow is not realistic, since even identical particles are measured with a certain error. Reconstruction of the realistic distributed diameter particle flow was approximated using the identical particle method. The optical mass flow sensor has major advantages over traditional methods. It is virtually insensitive to vibrations, contamination, temperature drift, and misalignment and the underlying measurement concept is well understood. But most importantly, the sensor does not require calibration. The mass flow of identical particles (4.5 mm air gun pellets) was measured with an error smaller than 3% even for high density flow rates.     

激光多普勒流动测量技术在颗粒流体两相流中的应用

分析介绍了激光多普勒流动测量技术的原理和用LDV／PDPA同时测定颗粒流体两相速度和粒径大小的基本方法，并进一步讨论了用LDV／PDPA测量颗粒浓度和两相流动动态特性的问题。