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前向插入式流速仪在工作时其探头会对待测流场造成干扰,该文对简化流速仪模型的干扰范围进行了测量和分析。简化模型仿毕托管(Pitot tube)形状,水平放置于明槽流场中,采用粒子图像测速(PIV)技术测得代表性平面瞬时二维流场。通过分析流场的沿程变化特征,确定了流速仪模型对其正前方水流的影响距离。实验结果表明:流向速度随距模型顶点距离的增大逐渐增加最后趋于来流速度,而水流的展向速度、紊动强度和雷诺应力(Reynolds stress)均随距模型顶点距离的增大而逐渐减小最后趋于稳定;流速仪对其前方水流的流速影响距离较大,对紊动强度的影响距离较小;流速仪对前方水流影响距离随模型直径增大而增大,在实验条件下,影响距离与模型直径成正比。
The forward plug-in flowmeter in the work of the probe will interfere with the measured flow field, the article to simplify the flowmeter model of the interference range were measured and analyzed. The simplified model was simulated in the shape of a Pitot tube and placed horizontally in the flume. The representative plane instantaneous two-dimensional flow field was measured by the particle image velocimetry (PIV) technique. By analyzing the variation characteristics of the flow along the course of the flow, the influence distance of the flowmeter model on the flow in front of it is determined. The experimental results show that the flow velocity increases with the increase of the distance from the model vertex, and finally increases with the increase of the distance from the model vertex. The velocity, turbulence intensity and Reynolds stress of the flow increase with the distance from the vertex of the model Gradually decrease and finally stabilize. The velocity meter has a greater influence on the flow velocity in front of the flow and a smaller influence on the turbulence intensity. The influence distance of the flowmeter on the front flow increases with the increase of the model diameter. Under the experimental conditions Under, the influence distance is proportional to the model diameter.