基于CFD灌溉机井管道液相流场的数值模拟

摘要

To improve the accuracy of the Jet lag ultrasonic flowmeter for the agricultural irrigation,the continuous flow field within pipeline of irrigation well is simulated with the standard k-ε model in Fluent software, the pressure nephogram and the velocity distribution in horizontal and vertical cross-section are observed to analyze the characteristic of fluid velocity distribution in pipeline.The average velocity correction formula of the pipeline is established and proved by the experiment.The results show that the pipe flow field is disturbed by the secondary flow of elbow,the velocity distribution of each section is obviously different and the measuring accuracy of the meter is reduced.After velocity correction,the measurement accuracy of the meter increases by 4.9%.%为改善农用灌溉时差法超声波流量计的测量精确度,利用Fluent软件中的标准k-ε模型对灌溉机井管道液相流场进行三维数值模拟,观察机井管道水平轴截面和竖直轴截面的压力云图以及速度分布图,分析管道内流体的速度分布特性,并在此基础上提出平均流速修正公式,对其进行实验验证.结果表明:受弯管二次流影响,出水管流场紊乱,各截面速度分布差异明显,降低了流量计测量精确度.经修正后流量计测量精确度提升了4.9%.