Active Control of Heat and Mass Transfer using Functional Jets Array

使用功能射流阵列主动控制传热传质

基本信息

批准号：
13450088
负责人：
HISHIDA Koichi
金额：
$ 8.83万
依托单位：
Keio University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2002
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-13450088/
关键词：
Turbulent mixing control Heat transfer control Feedback control Large eddy structure Vorticity Jet excitation Particle image velocimetry Synchronous real time measurement luternational Conferences

项目摘要

Control of scalar transport and local distribution is of significance for improvement of jet utilized fluid devices. Concepts of an array of jets and feedback control were introduced in order to control thermal fluid features. In the present study, three types of array of jets were investigated, that is, an array of triple parallel 2-dimensional air jets (width 15mm, nozzle spacing 50mm and Reynolds number 4000-8000), a staggered array of seven circular air jets (diameter 13mm, nozzle spacing 17mm and Reynolds number 1700-9500) and two parallel planar impinging water jets (width 10mm, nozzle spacing 36mm and Reynolds number 500-1000). Characteristics of the velocity field were examined in order to design control system by particle image velocimetry (PIV). In the first one, the exits velocity of the three jets were determined with feedback control based on the velocity distribution detected by an array of hot-wire probes in real time. Fluctuation intensity of the averaged velocity distribution was reduced and the system became robust with the recovering time shortened for disturbance. Neural network algorithm was applied to further complicated shape of velocity or concentration profile as a controller. In the second one, the relation between jets mixing and the ratio of the surrounding jets velocity was examined experimentally so that control system to realize the directional shape was achieved, which can rotate the orientation of concentration profile as a time sequential control. In the third one, manipulation of the local shear layers via the synthetic excitation through the fine slits at the nozzle exit was applied in order to control vorticies near the impinging plate. The present feedback control system showed the reduction of wall temperature fluctuation by the modification of vortices changing the pattern and the phase of the excitation.

控制标量传输和局部分布对于改善喷气用液体设备具有重要意义。引入了一系列喷气机和反馈控制的概念，以控制热流体特征。 In the present study, three types of array of jets were investigated, that is, an array of triple parallel 2-dimensional air jets (width 15mm, nozzle spacing 50mm and Reynolds number 4000-8000), a staggered array of seven circular air jets (diameter 13mm, nozzle spacing 17mm and Reynolds number 1700-9500) and two parallel planar impinging water jets （宽度10mm，喷嘴间距为36mm，雷诺数为500-1000）。检查了速度场的特征，以通过粒子图像速度法（PIV）设计控制系统。在第一个中，根据反馈对照确定了三个喷气机的出口速度，该速度基于实时通过一系列热线探针检测到的速度分布。平均速度分布的波动强度降低，系统变得稳健，恢复时间缩短了干扰。神经网络算法被应用于作为控制器的进一步复杂形状或浓度谱的形状。在第二个中，对喷气机混合与周围喷气机速度的比率之间的关系进行了实验检查，以便控制系统实现方向形状，这可以旋转浓度曲线的方向作为时间顺序对照。在第三个中，应用喷嘴出口处的细缝通过合成缝隙来操纵局部剪切层，以控制撞击板附近的涡旋。当前的反馈控制系统显示，旋转的修饰改变了励磁的模式和相位，壁温度波动的降低。