SLIP-FLOW IN SONIC NOZZLES FOR FLOW RATE MEASUREMENTS

摘要

Sonic nozzles are wildly employed as a flow standard owing to their advantages in mechanical simplicity and long-term stability. The flow behaviours through the nozzles in normal conditions are well understood. However, in the applications where the size and the operating pressure are very small, the continuum assumption begins to break. Slip-flow, which is beyond the scope of ISO9300, becomes dominant. The scope of this study is to validate the method used to predict the effects in the nozzle.