基于CFD的田间量水槽选型研究

A Comparison of Flumes in the Field Based on CFD

针对田间进水口的水量计量,以不同体型的量水槽为研究对象,利用AutoCAD软件建立了具有相同喉道宽度、不同喉道长度的量水槽三维数学模型,并基于计算流体力学软件FLOW-3D,采用RNGk-ε三维湍流模型和TruVOF方法对量水槽内的流动发展情况进行数值模拟。结果表明,无喉槽过槽水流流态变化迅速,流速分布不均匀,不易确定上游水深参考断面位置;长喉槽过槽水流流态稳定,流速分布均匀,但由于喉道段长度较长而占地面积较大、造价较高,且水头损失较大;短喉槽流场分布较为平稳,流速分布均匀,喉道段长度适宜,且水头损失小,适宜于我国北方灌区田间进水口的水量计量。

The three-dimensional mathematical model of flumes in the field was established by AutoCAD software .By combining RNG k-εturbulence model with TruVOF method ,the flow development of flumes in the field was simulated based on FLOW-3D software .The results indicate that it is difficult to locate the reference section of the upstream depth for the cut-throat flume owing to frequent changes of flow regime and uneven distribution of velocity .Although the flow regime was stable and distribution of veloc‐ity was homogeneous ,the long-throat flume occupied a large area owing to a long throat ,costs more and its head loss is bigger than others .The short-throat flume was suitable for water measurement in the field in North China ,because its flow regime was stable , distribution of velocity was homogeneous ,the length of throat was appropriate and head loss was small .