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摘要气体流速的测量在国民生产领域中一直有着极其重要的位置。但对于大空间内低流速的测量，由于其风速低，空间尺寸大，差压低，一直是测量领域的难题。本论文通过充分调研及查阅大量文献，基于时差法，设计了一大空间低流速气流超声测速装置，并以其为研究对象考察其可行性。围绕该目的本文开展了以下实验研究：
- 上一篇：低压配电柜测控与保护装置设计
- 下一篇：FLUENT 圆柱绕流的数值模拟研究
使用该装置在风洞条件下进行了实验，设置风速为 5m/s,7m/s,10m/s,13m/s,15m/s,20m/s,25m/s，基本涵盖常见气体流速。根据采集的数据使用 Origin 软件进行分析，测量结果与真实值符合得比较好。使用该装置在室外大空间自然风条件下进行了实验，测试风速为0.32m/s,1.83m/s,3.8m/s,4.5m/s,以热线风速仪的测量值作为参考值，实验得出结果与参考值符合得较好。以上实验很好的证实了设计的大空间低流速超声测速装置的可行性。19294
关键词:超声波测速，时差法，大空间，低流速
Title Ultrasound speed measuring device designed for
measuring low flow within large space
Abstract
Gas flow rate measurement has a very important position in the field of
national production. However, the measurement of low flow rates in large
space has been a problem in the field of measurement due to its low wind
speed, large space size and low differential pressure. In this paper, low
flow velocity of ultrasonic devices in large space is designed through
adequate research and access to a large literature based on the time
difference method, and its feasibility is also examined. The following
researches are carried out in this paper.
The devices used in the experiment are under the conditions of a wind
tunnel, the wind speed is set to 5m/s, 7m/s, 10m/s, 13m/s, 15m/s, 20m/s,
25m/s, covering the common gas flow. The data collected is analyzed by using
the Origin software, the measurement results are in good agreement with
the true value.
The devices used in large space are under natural outdoor conditions, with
the wind experiments testing velocity set to 0.32m/s 1.83m/s, 3.8m/s,
4.5m/s. The measured value of hot wire anemometer was taken as a reference,
which the experimental results accorded well with. The experiments above
well demonstrated the feasibility of the design for the low velocity
ultrasonic speed measuring device within large space.
Keywords Ultrasound Velocimetry,Difference Method,Large Space,Low Flow
目次
1 绪论...1
1.1 课题背景...1
1.2 超声波测速的发展...3
1.3 本文主要工作...4
2 时差法超声测速系统设计..6
2.1 时差法超声测速原理...6
2.2 超声波的发送与接收...7
2.2.1 超声波换能器7
2.2.2 驱动信号源和驱动信号放大器7
2.2.3 接收信号放大及采集7
2.2.4 换能器的安装方式8
2.2.5 工控机 8
2.3 时差法超声测速设计计算...8
2.3.1 系统总体设计计算8
2.3.2 风洞条件下的设计计算9
2.3.3 室外大空间条件下的设计计算..11
3 大空间低流速超声测速装置风洞实验研究... 12
3.1 风洞条件下实验系统.12
3.1.1 实验装置.. 12
3.1.2 实验步骤.. 12
3.2 风洞条件下实验数据.13
3.2.1 5～10m/s风洞实验结果.15
3.2.2 10～25m/s 风洞实验结果...16
3.3 风洞条件下结果分析.18
3.3.1 实验结果误差..18
3.3.2 实验结果分析..19
4 大空间低流速超声测速装置自然风实验研究... 20
4.1 自然风条件下实验系统.20
4.1.1 实验系统.. 20
4.1.2 实验步骤.. 21
4.2 自然风条件下实验数据.21
4.3 自然风条件下结果分析.24
4.3.1 实验结果误差..24
4.3.2 实验结果分析..24
结论...26
展望...28