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为了揭示不同进口流速情况下90°方形弯管内部流动特征,在构建90°方形弯管专用PIV试验台的基础之上,对弯管内不同断面以及不同半径上的流速分布情况进行了PIV测试试验。试验结果表明:采用PIV技术能较好地获得弯管内部流动情况;流体未进入弯曲段时,各断面流速分布变化不大;而进入弯曲段后,由于受到弯管壁的约束形成旋转流动,弯管内侧流速增大,外侧流速降低;当转过60°位置后,弯管内侧流速降低,外侧流速增加;到达90°位置后,各断面的流速基本趋于一致。不同半径处的流速分布不相同,弯管内侧流速较大,外侧较小,在50°、60°处流速达到最大值;弯管不同的进口流速对于速度峰值的位置有一定的影响,而对于弯管内其他的流动情况影响较小。
In order to reveal the internal flow characteristics of 90 ° square elbow under different inlet velocities, the PIV test was carried out based on the PIV test rig specially designed for 90 ° square elbow. test. The experimental results show that the PIV technique can well obtain the internal flow of the elbow pipe. When the fluid does not enter the elbow section, the flow velocity distribution of each section does not change much. When the elbow section enters into the bending section, The flow velocity inside the elbow increases and the outer flow velocity decreases. When the gas flow passes the 60 ° position, the flow velocity inside the elbow decreases and the outer flow velocity increases. After reaching the 90 ° position, the flow velocities in each section become basically the same. The flow velocity distribution is different at different radius, the flow velocity inside the elbow is larger and the outer side is smaller, the flow velocity reaches the maximum at 50 ° and 60 °. The different inlet flow velocity of the elbow has a certain influence on the position of the velocity peak, Elbow flow within the other less affected.