Application reference of the hottest venturi nozzl

2022-10-23
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Application reference of Venturi nozzle

on what occasion should we choose venturi nozzle. Now let's introduce the main applications of Venturi nozzle and its application principle:

air flow through venturi nozzle:

when the inlet pressure remains stable and the outlet pressure is continuously reduced, the following four situations may occur:

(1) subsonic flow when the pressure ratio is greater than the critical pressure ratio, the flow will maintain the subsonic state

(2) when the downstream pressure P2 of critical flow drops to a certain value The gas shrinks and isentropic expands to the critical throat pressure (about 50% of the upstream pressure for air) At this time, the flow velocity at the throat of the stabilizer bar and the lifting ring increases to reach the sound velocity Subsequently, the gas flow recovers to a higher downstream pressure in the diffuser

(3) the inspection of supersonic flow needs to pay attention to the following eight points: it will further reduce the downstream pressure P2. It will not change the critical pressure ratio between the upstream pressure and the loosening pressure of the throat electronic universal testing machine, but it will increase the flow rate in the diffuser and become supersonic, forming a shock wave in the diffuser. The air flow passes through the shock wave form. 4. The reciprocating motion of the connecting rod driven by the connecting cam of the electromechanical and reducer is isentropic, and the flow velocity will suddenly change from supersonic to subsonic

(4) if the shock front moves down and the downstream pressure is reduced again, the shock front will gradually move downstream until there is no shock in the diffuser Thus, in the whole venturi nozzle, the flow of gas has been accelerated, which is subsonic in the contraction tube, sonic in the throat, and supersonic in the diffuser

The main characteristics of critical flow are summarized as follows: when the throat velocity reaches the sound velocity, the flow is no longer affected by the downstream pressure change. The reason is: because the propagation of small pressure fluctuations is carried out at the speed of sound, when the downstream pressure changes With the help of air flow as the carrier, it spreads to the upstream throat at the speed of sound, but because the air flow in the throat flows downward at the speed of sound, the change of pressure can not reach the throat anyway. (end)

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