中文摘要：

多孔孔板流量计尾流流动特性是影响计量性能的关键,为了分析节流孔前后倒角对尾流流动特性的影响规律、优化多孔孔板结构,针对DN100、节流比为0.67的多孔孔板,本研究利用CFD技术对带倒角多孔孔板的尾流流场进行计算,从而揭示节流孔前后倒角对计量性能的影响规律,并利用实流实验进行验证。研究结果表明：前倒角是降低永久压力损失的关键因素,但无法提高计量精度,当前倒角在30°~60°时,永久压力损失为相同节流比的标准孔板的50%,流出系数线性度误差随前孔倒角角度的增大而提高,当前倒角为60°时,与无前孔倒角的多孔孔板流量计线性度误差接近;在45°~60°范围内,后倒角对尾流流场具有较好调整作用,从而拓宽量程范围、提高计量精度。由此得出,前倒角为60°、后倒角在45°~60°范围内的多孔孔板计量性能有较大的提高。

英文摘要：

The wake flow characteristic is the key factor to the metrological performance of multi-hole orifice flowmeter. In order to investigate the influence of chamfer on wake flow characteristics and optimize the structure of multi-hole orifice, the wake flow field of multi-hole orifice with front and back chamfers, throttle ratio 0.67 and DN100 is calculated by CFD technology, the influence rule of front and back chamfers on multi-orifice metrological performance is revealed in this paper. The conclusion can be drawn that front chamfer is the key factor to reduce the permanent pressure loss, but unable to improve the measurement accuracy. Compared to standard orifice with the same throttle ratio, the permanent pressure loss of multi-hole orifice with front chamfer within the scope of 30° -60° was reduced by 50% , discharge coefficient linearity error decreases as the front chamfer＇ s angle increases, eventually closes to linearity error of multi-hole orifice flowmeter with 0° front chamfer. Within the scope of 45° -60°, back chamfer has a better effect on the flow field adjustment, thus the scope of range is broadened and the measurement accuracy is improved. It follows that the metrological performance of the multi-hole orifice with 60° front chamfer and 45° -60° back chamfer is improved obviously.