EXPERIMENTAL INVESTIGATION ON CRITICAL FLOW THROUGH MICROORIFICES AND CAPILLARIES |
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| Kazuto Kawakita, Marcos Tadeu Pereira |
- Abstract:
- With the purpose of studying application of critical flows through small orifices in the measurement and control of very low gas flowrates, experimental investigations were carried out on a set of 22 microorifices and capillaries of circular cross sections manufactured out of ruby and stainless steel. Diameters of the orifice and capillary samples ranged from 16 µm to 427 µm, and their lengths from 254 µm to 68 mm. The microorifices were submitted to tests using air, argon, helium and carbon dioxide, and the back to the upstream pressure ratio Pb / P0 varied from unity down to about 0,1, both under pressure and vacuum operations. Results showed that, when operating under vacuum, the critical flow regime indicates that the discharge coefficient is stable and choking occurs even in flows with very small Reynolds numbers. However, when operating under pressure, the critical flow regime depends on the pressure ratio Pb / P0 , and other parameters related to the gas properties and the orifice dimensions. Experimental results also showed that compressibility factor is a fundamental parameter to be considered in critical flows through microorifices, mainly when operating under a pressurized condition.
- Keywords:
- microorifices, capillaries, critical flow, compressible flow, microflows
- Download:
- IMEKO-TC9-2000-066.pdf
- DOI:
- -
- Event details
- IMEKO TC:
- TC9
- Event name:
- FLOMEKO 2000
- Title:
- 10th Conference on Flow Measurement
- Place:
- Salvador, Bahia, BRAZIL
- Time:
- 04 June 2000 - 08 June 2000