Application of throttling device for the hottest c

2022-10-13
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Application of critical flow throttling device

when the standard throttling device is applied to compressible flow (gas), the ratio of downstream pressure to upstream pressure (i.e. pressure ratio) is not less than 0.75. At this time, the fluid flow velocity in the pipeline is subsonic. When the downstream pressure continues to decrease, a critical flow image will be generated on the more moving channel of the flow fixture with a profiled throttle piece, and the flow velocity at the throat of the flow piece will reach the sound velocity at this time The flow is blocked Although the downstream pressure continues to decrease The mass flow through the throttling element will remain constant Only when the upstream pressure increases, the mass flow will increase again

in practical applications, critical flow Venturi nozzle (sonic venturi nozzle used to manufacture individual prostheses and ultra light aircraft structures) or sonic venturi is widely used in gas flow measurement. For example, in the natural gas industry, as the standard of gas flow transmission and pressure stabilizer, it has been widely used, and its main characteristics are as follows:

① the theoretical basis of instrument work is relatively clear, which can be used as 1 The forming condition is expressed by a semi meridional formula The outflow coefficient calibrated on the original gas standard can be extended to different operating conditions without losing measurement accuracy

② the instrument has high repeatability

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