基于CFX的旋进旋涡流量计取压位置的数值模拟

Numerical simulation of pressure tapping location of precession vortex flowmeter based on CFX

针对旋进旋涡流量计的精确测量,使用CFX数值模拟软件对旋进旋涡流量计内部流场进行数值模拟,确定了旋进旋涡流量计的最佳取压点.分析了旋进旋涡流量计的工作原理;建立了旋进旋涡流量计的三维数字化模型,使用基于有限元的有限体积法对旋进旋涡流量计内部流场的流动特性进行数值模拟研究,得到了明显的类似于钝体涡街旋涡脱落现象,并根据稳定状态下取压点压力变化曲线使用傅里叶变换得到傅里叶级数以确定流量计的脉动频率;使用音速喷嘴装置进行试验并将试验结果与数值模拟数据进行对比分析,验证了使用CFX对旋进旋涡流量计进行数值模拟的可靠性;分析不同流量下不同取压点的压差,得到了旋进旋涡流量计内流场压力变化的一般性规律,确定了旋进旋涡流量计在喉部与扩张段连接处的压差为最大,此处可以作为压电传感器的最佳取压位置.

For the accurate measurement of precession vortex flowmeter,the numerical simulation software CFX was used to conduct numerical simulation on the internal flow field of precession vortex flowmeter,and the optimal pressure measurement point of precession vortex flowmeter was determined.The working principle of precession vortex flowmeter was analyzed.The 3D digital model of precession vortex flowmeter was established.The flow characteristics of the internal flow field in precession vortex flowmeter was obtained by using the numerical simulation research with the finite volume method based on finite element.The obvious vortex shedding phenomenon similar to the bluff body was obtained.The pulsation frequency of the flowmeter was determined according to the pressure change curve of the pressure point under the stable state using Fourier transform to obtain the Fourier order number.Experiments were carried out using the sonic nozzle device and the test results were compared with the nume-rical simulation data.The reliability of the numerical simulation of precession vortex flowmeter using CFX was verified.The differential pressure at different pressure measurement points under different flows was analyzed,and the general law of pressure variation in flow field in precession vortex flowmeter was obtained.It was confirmed that the maximum differential pressure at the junction of throat and expansion section of precession vortex flowmeter was found,which could be used as the optimal pressure measurement position of piezoelectric sensor.