翼柱型量水槽水力特性分析与对比

【目的】为探究翼柱型量水槽在自由出流和淹没出流时的量水性能。【方法】试验观测10种流量条件下,量水槽进口到出口13个测流断面的水位,对自由出流和淹没出流两种工况下的水面线、佛汝德数、测流精度等水力参数进行分析与对比。【结果】自由出流状态下在断面11到断面12之间形成了临界流,流量在0.044 m3/s以下时没有产生临界流从而得到了U形渠道翼柱型量水槽的最小工作流量。翼柱型量水槽过槽流量与上游水深具有良好的相关关系,通过拟合得到了自由出流和淹没出流状态下的流量公式,其中自由出流状态下最大误差为-2.54%,淹没出流下为6.50%,二者平均误差均小于0.3%,满足现行渠道量水规范的误差要求。本文拟合的淹没出流流量公式最大淹没度高达0.958,适用范围较大。此外,U形渠道翼柱型量水槽具有较大的自由出流范围,临界淹没度可达0.890。【结论】经试验确定临界流断面位于距进口约为量水槽4倍翼高处。翼柱型量水槽可满足小比降既成渠道的测流要求,进一步解决了量水槽流量公式在淹没出流情况下测流误差较大的问题。

Comparative Analysis on Hydraulic Characteristics of Wing Pillar-shaped Measuring Flume

【Objective】The purpose of this paper is to explore water performance of wing pillar-shaped measuring flume in free outflow and submerged outflow.【Method】The water levels of 13 flow measuring sections from the inlet to the outlet of the measuring flume under 10 kinds of flow were observed through experiments, and the hydraulic parameters such as water surface line, the Froude number and flow measurement accuracy under free outflow and submerged outflow conditions could be analyzed and compared.【Result】Critical flow was formed between section 11 and section 12 under free outflow condition. And the minimum applicable flow rate of this type flume in U-shaped channel was 0.044 m3/s. The analysis results showed that there was a good correlation between flow rate and upstream water depth. Then the flow formula of the flume under free and submerged outflow conditions was obtained by fitting. The maximum error of free outflow was-2.54% and that of submerged outflow was6.50%. The average error of both was less than 0.3%, which meets the error requirements of current channel water measurement standards. The maximum submergence degree of the submerged outflow formula fitted in this paper was as high as 0.958, which had a wide application range. In addition, wing-column measuring flume in Ushaped channel had a large free outflow range, and the critical submergence degree could reach 0.890.【Conclusion】The critical flow section was located at 4 times the height of the wing of the measuring flume from the inlet.The wing pillar-shaped measuring flume could satisfy the requirement of flow measurement in small slope channels, and it solves the large error of the flow formula under the submerged outflow conditions.