上游双弯头对内锥流量计性能的影响

为提高对内锥流量计安装与使用条件的认识,开展了上游连续两个90°在同一平面成S型结构和互成垂直平面上弯头的数值仿真与实流实验研究.研制了实验样机一套,β值分别为0.45/0.65/0.85.利用平均流出系数相对误差及附加不确定度作为安装条件影响的主要评价标准,研究结果表明:对于β值分别为0.45/0.65/0.85的内锥流量计,在互成垂直面双弯头安装条件下所需最短直管段长度均为1D;在同平面S型双弯头安装条件下所需最短直管段长度分别为1D/1D/2D.

Effects of upstream double pipe elbows on the performance of cone flowmeter

In order to acquire a deep knowledge of installation requirements and application conditions, numerical simulation and experiment investigation have been carried out with double closed 90° elbows in "S" shape on the same plane and double closed 90° elbows on two mutually vertical planes. A prototype with three kinds of structure was developed, in which the equivalent diameter ratios are 0.45/0.65/0.85 respectively. Using the relative error and additive uncertainty of the averaged discharge coefficient as the main evaluating criterions, and results indicate that for three kinds of equivalent diameter ratios, the shortest straight pipe length of the cone flowmenter is 1D/1D/1D for the vertical planes and 1D/1D/2D for the same plane.