涡街流量传感器在二维和三维流场中特性之比较

涡街流量传感器中的涡街现象存在于三维管道中，其信号特性表现出与二维情况较大的差异．研究这种差异对于涡街流量传感器的设计以及三维建模具有十分重要的意义．通过在近似二维流场（水槽中）以及三维流场（管道中）的实验，发现管道中的涡街频率比水槽中高出至少1倍，且最强信号出现的位置比水槽中更靠近旋涡发生体，由此引发了对二维、三维涡街流场特征的研究．通过数值仿真，揭示了造成差异的原因是管壁的约束作用以及涡管的扭曲，同时对涡街流场的速度分布等特征进行了分析．

Comparison of Performances of Vortex Flow Sensor in Two-Dimensional and Three-Dimensional Flow Field

The vortex flow field in vortex flow sensor exists in three-dimensional pipes and its characteristics are different from those in the two-dimensional vortex street phenomenon. Comparison of the difference between the two flow conditions is significant to the design and modeling of the sensor. Experiments carried out in the water channel （two-dimensional） and pipe （three-dimensional） show that the vortex frequency in three-dimensional flow is at least twice that in two-dimensional flow and the position of the most intensive signal is closer to the bluff body. Numerical simulations were carried out to study the characteristics of two-dimensional and three-dimensional flows, the results of which indicate that restraint from pipe wall and torsion of vortex are the reasons for the difference. Furthermore ,the characteristics of vortex flow fields were analyzed.