面积流速仪在明渠流量监测中的应用

Application of Area Flow Meter in Open Channel Flow Monitoring

结合前人对矩形断面明渠流速分布的理论分析与试验研究,应用大量的试验数据,建立明渠流量测定的代表断面、代表垂线和代表水深,可以提高实际明渠流量测定精度,简化明渠流量测定工作量.结果表明：实际流量监测中,量断面最好选择在渠宽4倍的距离以上,如果不满足条件,渠越宽,需要的相对流程越短;越窄,相对流程越长.监测水深时,在y=0.4h处作为监测点,在水流波动较大的水中,也可以选择应用0.2h、0.6h和0.8h三点法,但不建议选择0.2h和0.8h的两点法.监测垂线的选择为：在≤3.0m的明渠上,一般取3条垂线就可以代表平均值,第1条垂线选择应距离渠壁大于10 cm,在0.1＋（0.5 b-0.1m）/2～0.5 b范围内平均设置另外两条垂线.

On this basis of the previous theoretical analysis and experimental study of the rectangular open channel flow distribution, as well as a large number of experimental data, this paper established the representative cross-section, representative vertical line and representative wa- ter depth for the open channel flow monitoring, which could improve the accuracy and simplify the workload of open channel flow monitoring. The results showed that in the actual flow monitoring, the cross-section should be located at the distance 4 times of the channel width or above ; if the conditions cannot be met, a wider channel needs a shorter relative flow path, and a narrower channel needs a longer relative flow path. In water depth monitoring, y = 0, 4 h is taken as the monitoring point, or in water with violent waves, 0.2 h, 0.6 h and 0.8 h can be taken as three-point monitoring, but two-peint monitoring （0.2 h and 0.8 h） is not recommended. The monitoring vertical line is defined as： for an open channel ≤3.0 m, 3 vertical lines are taken to represent the mean, the first one should be 10 cm or further away from the channel wall, and the other two set evenly within the range of 0. 1 ＋ （0.5 b -0. lm）/2 -0.5 b.