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介绍一种用于核电厂排风烟道流量测量仪表——皮托-文丘里复合管。该表能在低的气体流速下得到较大的差压信号,差压值随流速变化率大、灵敏度高、阻力损失小。该表置于烟道中心区。从流体力学观点导出该表的放大倍数和流量系数的解析关系式。根据相似理论及流体流动具有稳定性和自模性的特性,通过1/12烟道模型试验找出实际烟道中心的流速与平均流速的关系。再根据排风烟道的流量范围,把皮-文复合管在回流风洞上标定,最后给出了可供烟道流量测量用的流量系数。这是常规仪表难于实现的。
Describes a for nuclear power plant exhaust flue flow measuring instrument - Pitot - venturi composite pipe. The table can be at a low gas flow rate to obtain a larger differential pressure signal, differential pressure value with the flow rate of change, high sensitivity, resistance loss. The table is placed in the center of the flue. From the hydrodynamic point of view, we derive the analytic relation between magnification and flow coefficient of this table. According to the similarity theory and the characteristics of fluid flow with stability and self-mold, the 1/12 flue model test was used to find out the relationship between the actual flow velocity and the average flow velocity. According to the flow range of the exhaust flue, the skin-text composite pipe is calibrated on the return wind tunnel, and finally the flow coefficient for the flue gas flow measurement is given. This is difficult to achieve by conventional instruments.