基于上游渐扩管安装条件的内锥流量计性能预测

Prediction of the performance of cone flowmeters installed with an upstream expander

针对内锥流量计使用灵活性要求，利用计算流体动力学数值仿真和实流实验相结合的方法，研究上游渐扩管安装条件对内锥流量计性能的影响，以获取所需的最短直管段长度。研究对象是100mm口径、β值分别为0．45，0．65，0．85三种结构类型的样机。开展了基线和渐扩管两种类型的实验，仿真和实验的介质均为常温水，雷诺数范围分别为0．2488×10^5～2．488×10^5和0．3843×10^5-2．479×10^5，仿真结果和实验结论一致。利用附加不确定度和流出系数相对误差作为主要的评价标准，给出了上游渐扩管安装条件内锥流量计所需的直管段长度。

Based on numerical simulation and actual-flow experiment, the influence of the in- stallation of upstream expander on cone flowmeter is investigated to obtain the minimum length of straight pipe within flexibility requirements. The objects of study are three types of prototype with 100mm diameter and p values of 0. 45,0. 65,0. 85. The medium of simulation and experiment is water with ambient temperature, and the Reynolds are 0. 2488）〈 105~2. 488 X 10s and 0. 3843 × 10^5 -2. 479×10^5 respectively. Two types of experiments are carried out, namely, the baseline and expander experiments. Evaluated in terms of additional uncertainty and the relative error of discharge coefficient, the required length of straight pipe of cone flowmeter is given after the in-tallation of an upstream expander.