Research Article
Measurement of Annular Flow for Drilling Engineering by Electromagnetic Flowmeter Based on Double-Frequency Excitation
Table 2
Comparison of response speed.
| | State of butterfly valve | State of flow | Standard EMF | Principle prototype |
| | Fully open⟶half open | Flow variation (m3/h) | 60⟶34 | 60⟶34 | | Response time (s) | 7.9 | 4.7 |
| | Half open⟶fully open | Flow variation (m3/h) | 34⟶60 | 34⟶60 | | Response time (s) | 7.2 | 4.3 |
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