速度分布

Acousto-optic scanning laser Doppler anemometry , in which the acousto-optic deflectors are used to controll the position of the LDA measurement volume, is a newly developed technique for measuring the spatial distributions and temporal properties of flow field.

通过对空间速度梯度和空间速度分布测量技术的分析与比较，作者认为使LDA测量点位置移动的激光扫描测速技术是诊断空间速度分布的好办法，并针对机。。。

Generally speaking, the high group velocity and low attenuation factor and high Q〓 in the same area, but relatively low group velocity and high attenuation factor and low Q〓 in the same area in China is the general distribution.

在不同周期，面波衰减系数或品质因子在整个中国大陆区域分布是不均匀的；总体表现为高群速度分布的区域呈现高Q〓和低衰减系数、低群速度分布的区域呈现低Q〓和高衰减系数分布的特点。

Consequently the diathermancy was strengthened, the effect of heat transfer was improved and the flow and combustion process in the boiler has become much better. First, in this thesis the burn characteristic of the rubbish and the process of combustion in the chain boiler has been studied. A series of mathematic model has been given. This thesis carefully introduced the principle and formula of the turbulent flow model、two-equation model、radiation model、dispersed phase model and standard wall function method. The software FLUENT has been applied to simulate the temperature、pressure、velocity and mass fraction of species in the boiler furnace and stokehole. The analysis and the comparison have been done. The calculation results indicate agreement with the fact and the studies both here and abroad.

首先，本文针对SZL10-1.25-MJ造纸垃圾焚烧锅炉，结合其燃料的特性，对垃圾的燃烧特性以及层燃炉中垃圾的焚烧过程进行分析；给出一套完整的垃圾锅炉炉内传热数学模型，并分别详细阐述了湍流流动模型、双方程模型、辐射传热模型、离散相模型及标准壁面函数的原理及计算公式；借助于Fluent软件平台对炉膛内的温度场、速度场、组分浓度场及炉膛出口的温度分布、速度分布、组分浓度分布等进行数值模拟，分别从定性和定量的角度与实际情况进行了比较，得到了较满意的结果；模拟结果与国内外的很多研究能较好符合。

The main research work of this paper are focused on following areas:(1) Based on review of the theory and methods on measurements of particle fields, a new idea for obtaining particle size and velocity distribution within a spray through imaging the particle field with a laser light sheet was put forward;(2) A DPIV (Digital Particle Image Velocimetry) system, is fit for velocity measurements of low speed flows, was developed and expended to particle size distribution measurement;(3) An arithmetic for particle velocity field reconstruction was developed, and the velocity distribution of water mist was also obtained;(4) A software system for particle analysis, which based on image geometry emend, de-noise and image partition was developed, the parameters such as particle size distribution, mean diameter, number of particles, minimum and maximum diameter can be got with this system;(5) A water mist system was developed and its characteristics, such as droplet velocity, size distribution, number of droplets and spray cone angle under different conditions were obtained from experiments with PIVS;(6) The measurement results of water mist characteristics with PIVS were compared and analyzed with the simply simulated results, and in addition, in order to verify the accuracy of PIVS, some experiments were conducted with the standard particles, such as glass-ball with known mean diameter of 50μm and 115μm, metallic coated tracing particle with mean diameter of 12μm;(7) Some experimental studies on interaction of water mist with liquid pool fires were conducted.

本论文的主要工作包括以下几个方面：（1）在对粒子场测量的相关理论和具体方法进行综述分析的基础上，提出了通过采用激光片光对粒子场进行成像以获取其粒径和速度等参数分布的新思路；（2）研制了适宜于低速流动速度场测量的DPIV(Digital Particle Image Velocimetry)系统，并使其实现了对粒子场粒径分布的测量功能；（3）研制了基于粒子运动轨迹的速度场重建算法，获取了细水雾雾场的速度分布；（4）研制了基于几何校正、去噪、图象分割等图象处理方法的"粒度分析软件系统"，该系统既可分析给出粒子场的粒径分布直方图和平均粒径，还可给出粒子的数目以及最大、最小粒径等信息；（5）建立了一细水雾发生系统，并应用上述方法对不同压力条件下细水雾系统的雾场特性（如速度分布、雾滴粒径分布、雾滴的数目、喷雾张角以及雾化长度等）进行了实验测量研究；（6）对细水雾特性参数的PIVS测量结果与计算机简单模拟计算结果进行了定性比较分析，并利用平均粒径为50μm和115μm的玻璃球以及12μm的标准示踪粒子对PIVS系统的粒径和速度测量结果进行了实验验证，同时对其局限性进行了分析讨论；（7）对不同工况条件下细水雾与油池火相互作用的过程进行了模拟实验研究。

This thesis is aimed to study the flow field in Circulating Fluidized Bed holier in cold state based on the system of Particle Image Velocimetry, Several parts are included: the distribution of particles velocity in CFB boiler including radial velocity and axial velocity of particles; the average radial and axial concentration distribution of particles in CFB boiler; the average radial and axial size distribution of particles in CFB boiler.

本文采用PIV系统对循环流化床锅炉冷态流场进行了试验研究，研究的主要内容包括：循环流化床冷态流场粒子的速度分布特性，包括粒子的径向速度和轴向速度分布；循环流化床颗粒的平均浓度沿径向和轴向分布特性；循环流化床颗粒平均粒径的轴向和径向分布特性。

The mean velocity distributions in turbulent boundary layers of smooth surface and two different riblet surfaces are measured with IFA300 constant-temperature anemometer in low-speed wind tunnel to validate the full development of turbulent boundary laye. Friction velocity and wall friction stress of turbulent boundary layer are obtained with the least-squares fitted curve of the sublayer velocity distribution based on Spalding formula, and virtual origin position of riblet surface can be acquired accurately.

在低速风洞中来流速度一定的情况下使用IFA300恒温热线风速仪测量了光滑表面和两种不同尺寸的脊状表面湍流边界层平均速度分布剖面，并验证了试验段湍流发展的充分性；通过应用Spalding壁面公式使用最小二乘法精准拟合了实验测量的边界层内层速度分布曲线，得到了湍流边界层壁面摩擦速度并进一步求得湍流壁面摩擦应力，较准确地计算出脊状表面的虚拟原点位置，并通过与对数律公式拟合结果比较分析，证实了该方法更加准确有效。

Under maximal flux (Vi = 4.3 m/s),fluid field of 16 cross sections in the model were investigated, the tangential velocity empirical equation of each partition was got, and empirical equations of axial and radial velocity on the ring partition between baffle bar and cylinder wall were obtained.

在全气速（Vi = 4.3 m/s）下测得了流场中各部分共计16个截面的流场分布，分别拟合得到各区域外旋流中切向速度分布经验公式；拟合得到在导流体与筒壁间环形段轴向速度分布和径向速度分布经验公式。

Flow disciplinarian of different PH indicator polymer solution and newtonianliquid in annulus line had been studied, and found speed distributing, vortex,streamline of annulus line, analytic flow field distributing in annulus and eccentricsituation and compared the results with prevenient schloar, some results different fromprevenient results are get, shch as the relation of average velocity and maxiumvelocity is not less with the viscosity exponent under the annular line, the fluid speedaffect the relation.

应用 PIV 分别研究了不同浓度的聚合物溶液以及牛顿流体在垂直环空管道中的流动规律，得到了环空管道中流体的速度分布情况、涡量情况、流线情况，分析了同心和偏心情况下环空管道内的流场分布规律，并与前人的计算结果进行了比较，得出了一些与以前不同的结论：同心情况下平均流速与最大流速的关系，并不是完全与粘性指数 n 值有关系，还与管道内流动的流动速度有关系，当速度较小时，两者的差别就小，速度大时，不符合这种规律。

The second part of this paper presents a CFD-simulation of the performance of straight-walled and curved-walled micro nozzle/diffuser by FLUENT software. Such nozzle/diffusers are mainly used in micro venturi and also applied to valveless micropumps.

而在速度分布部分，当流量为5.338 mg/min时，宽度为150微米的喉部区流速已经高於声速，随后因速度不断增加，空气黏滞力影响了速度分布而产生了速度冲击现象。

The distributions of velocity, velocity gradient, shear stress, clongation stress, first normal stress difference and pressure of the flow of a power-law fluid in the profile die were analyzed. It indicates that for a power-law fluid only after a few iterations a good convergence can be reached, even though in the case of high extrusion velocity.

本文分析了幂律流体在异型材挤出口模内的速度分布、速度梯度分布、剪切应力分布、拉伸应力分布、第一法向应力差分布和压力场，研究表明采用幂律流体模型，即使在挤出速度非常大的情况下，经过有限次迭代，模拟计算都能够收敛，并得到合理的结果。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。