关键因素对内锥流量计压损的影响

Effects of key factors on the pressure loss of V-cone flowmeters

为提高对内锥流量计压力损失的认识,获得高准确度的压损计算公式,开展了关键因素对内锥流量计压损影响的实流实验研究。实验介质为常温水,雷诺数范围0.14×105～4.2×105。设计等效直径比分别为0.45、0.55、0.65、0.75、0.85的实验样机一套,从永久压损与相对压损2个角度进行分析。研究表明,一方面等效直径比相同而雷诺数不同时,内锥流量计的永久压损随雷诺数的增大而增大,在对数坐标系下成线性关系;雷诺数相同而等效直径比不同时,永久压损随等效直径比的增大而减小;另一方面,内锥流量计的相对压损与雷诺数无关,与等效直径比相关,随等效直径比的增大而减小。将本研究给出的内锥流量计相对压损计算公式与国外公式预测结果进行了比较,最大偏差为21%;同时,与国外测试的不同流量计相对压损曲线进行了比较,得出本套样机相对压损曲线介于孔板和喷嘴之间,且更靠近孔板的结论。

In order to acquire a deep knowledge of the pressure loss performance and obtain high accuracy pressure loss calculation formula of V-cone flowmeter, experiment investigation has been carried out, which is about the effects of key factors on the pressure loss of cone flowmeter. A set of prototypes are designed and manufactured, viz. a V-cone flowmeter of 100 mm interior diameter with equivalent diameter beta ratio of 0.45, 0.55, 0.65, 0.75, and 0.85 respectively. The experiment medium is water of normal temperature with Reynolds range of 0.14×105~4.2×105. The test data are analyzed from two different aspects, the permanent pressure loss and relative pressure loss. On one hand, the test results show that for V-cone flowmeter the permanent pressure loss increases along with the decrease of equivalent diameter beta ratio on the condition of the same Reynolds number; and increases with the increase of Reynolds number on the condition of the same equivalent diameter beta ratio. On the other hand, the experimental results prove that the relative pressure loss increases along with the decrease of beta ratio and is independent of Reynolds number. Compared with the results from foreign research institutes, the maximum deviation of the relative pressure loss in our study is approximately 21%. Compared with the curves of the relative pressure loss of other flowmeters studied abroad, the obtained curves of the beta ratio and relative pressure loss fall in between the two curves of orifice and nozzle, and are closer to the curves of orifice.