文档介绍：摘要
摘要
明渠流量计是一种使用广泛的流量计量仪器,具体应用在供排水、水利工程和农业灌溉等领域,它的计量准确性直接关系着国计民生。目前,对明渠流量计的检定仅停留在实验室阶段,且实验室检定可操作性也差;现有的对现场明渠流量计的校准没有一个可靠的依据,即使尝试着进行现场校准工作,其做法是主要先对影响明渠流量计计量特性的相关物理参数,如明渠的堰槽尺寸、水位转换器等参数进行在线测量,依次计算出各分量不确定度,然后再合成为明渠流量计流量的总不确定度。这种方法没有考虑安装影响,对堰槽的制作影响估计又过于保守,且测量项目多且较复杂,不利于计量工作的开展。因此,有必要研究现场明渠流量计校准方法,进而形成通用的现场校准规范,使现场校准有据可依,既能提高在线计量校准效率,又能保证计量活动准确有效。
本课题对明渠流量计在线校准规范的探讨与提出,意在避免上述可能的缺点,使明渠流量计在线校准能够成为可能。它的提出与改进,一方面能够使计量检定人员更加便捷高效地对现场使用中的明渠流量计进行校准;另一方面也有利于规范对明渠流量计前部整流渠段具体设计的参数,保障明渠流量计测量的准确度。
本课题是利用一组高精度的流速仪,设计出不同的布点方案,测量在明渠流量计前部整流段某一适当截面上所定点处的实际流速值,之后引入内插方法,通过若干个流速特征点,利用内插公式扩展计算出更多的流速值,通过速度—面积法计算出流量值,并累加各微元流量值,得到明渠的瞬时流量。最后,再利用试验系统中的标准表—电磁流量计与上述两种方法所得流量进行误差比较,以此来评价内插法的实测精度,并找出内插法与流量真值之间的比例关系,作为修正系数。如何将内插法测量明渠流量应用到对明渠流量计的在线校准工作中,本文做了初步总结,这为明渠流量计在线校准规范的提出做了理论铺垫。
关键词明渠流量计流速仪内插法速度—面积法在线校准
Abstract
Abstract
As a flow measuring instrument, open channel flow meter was widely used in urban water supply aqueducts, thermal power plant cooling water diversion and drainage, sewage treatment inflow and outfall, industrial and mining wastewater discharge and water
conservancy and agricultural irrigation channels and other fields, the accuracy of the measurement is directly related to people's livelihood. At present, the test of open channel flow meter only carried out in the laboratory, and maneuverability in laboratory is not good; there is no a reliable basis in current on-site open channel flow meter calibration, even we try our best to conduct on-site calibration, the main work was to get the relevant physical parameters on the characteristics of the impact of open channel flow meter, such as the parameters of the open channel weir tank size, water level converter, calculated the uncertainty of ponent, and then synthesize them. This method does not consider the impact of installation, and underestimated the impact of the making of the weir trough, it was not suitable to carry out the test for plex. Therefore, it is necessary to study the field open channel flowmeter calibra