<p> An investigation of the technique of obtaining the wall shear stress in a two-phase flow, by measuring the mass transfer coefficient at the wall with the electrochemical method, has been completed.</p> <p> The experiments involved the measurement of flow rates, pressure drops, void fractions and mass transfer coefficients, for a cocurrent upwards gas-liquid flow in a vertical tube, 13 mm in diameter. The liquid phase was an electrolyte consisting of 1.0 to 3.0 molar sodium hydroxide, and 0.005 to 0.010 equimolar potassium ferricyanide and potassium ferrocyanide. The gas phase was nitrogen. The flow regimes studied were slug, churn and annular.</p> <p> Emphasis is placed on the measurements obtained with the electrochemical method. Its application, advantages and disadvantages are detailed. A series of single-phase experiments were performed to explore the characteristics of the method and to serve as benchmarks for the two-phase experiments.</p> <p> The space-time-averaged values of the mass transfer coefficient were found to give the wall shear stresses to an
accuracy of ±20%. Frequency analysis of the local fluctuating values indicate that measurements of the local mass transfer coefficient can be used for flow regime identification.</p> <p> The theoretical flow regime map of Dukler and Taitel successfully predicted the flow regimes. The correlations of Griffith and Wallis, and Lockhart and Martinelli as modified by Davis, predicted the pressure drops and void fractions to an accuracy ±15% when applied to the appropriate flow regimes. As a further exercise, the force interactions between the phases, referred to as the interfacial shear terms, were calculated from both the measured and predicted void fractions and pressure drops.</p> / Thesis / Master of Engineering (MEngr)
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/20314 |
| Date | 01 1900 |
| Creators | Surgenor, Brian W. |
| Contributors | Banerjee, S., Engineering Physics |
| Source Sets | McMaster University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis |
Page generated in 0.0019 seconds