| Wafer Cone meter is a new type differential pressure meter which is later developed and less researched. However, the meter has proved having advantages as stabilization, low pressure loss and wide measurement range. Expansibility factor is one of the main parameters of the Wafer Cone meter, so it is of great significance for understanding its varying mechanism and finding out calculating methods with high accuracy. Wet gas is a particular regime of multi-phase flow. Wet gas measurement is a weighty branch of multi-phase measurement. People have working on the subject for decades, but still a large number of problems are left to solve due to its complex, hard-to-depict flowing mechanism. Though it has being widely accepted that The Wafer Cone meter performed well on single-phase metering, the issue that metering wet gas using this meter is less investigated. This dissertation focuses on characteristics of the Wafer Cone meter on its expansibility factor as well as wet gas metering on low pressure condition, and looks forward to making progress both on theory and on practice for the future applications.The primarily research works of the dissertation are as following:1. A fitting scheme of expansibility factor of the Wafer Cone meter is deduced theoretically from basic principles and equations of fluid mechanics.2. A numerical simulation scheme is put forward to predicting expansibility factor of the Wafer Cone meter. Adopted this scheme, a set of simulations were carried out. The computational predictions were compared with the results of physical experiments and shown that the expansiblity factors of the Wafer Cone meter by numerical simulations remarkably approached test results. The average full scale deviation is less than 2.5%; the maximal full scale deviation is of 5.42%. The contours of pressure and density as well as the vector of velocity in flowing region were obtained from simulations. By means of analyzing the contours and the vector, the dissertation made the relationship between predicting accuracy and equivalent diameter ratio clear.3. Theoretical formulaes of pressure drop due to friction and accelerating respectively in convergence segment of the Wafer Come meter were deducted from the two-phase separated-flowing momentum equation. Then, based on the formulaes, a theoretical model concerning the"Overreading"of the Wafer Cone meter in wet gas metering was advanced and discussed.4. A new"Overreading"correcting model was built up by experimental data. Validations were carried out correspondingly and shown that the model has the maximal relative error of 6% and the average relative error of 2.5%. It goes without saying that the model works well on Overreading predicting.5. Another numerical simulation scheme was advanced on wet gas measuring. The settings of discrete phase model (DPM) were deeply investigated. The procedure of simulation was represented and commented. The simulations corresponding with physical experiments have been carried out by commercial CFD software FLUENT. Comparing between simulation predictings and experiment data, the results indicate that the maximal relative error of simulations is less than 5%; the average relative error is less than 2.7% when equivalent diameter ratio are of 0.65 and 0.75. Similarily, when equivalent diameter ratio is of 0.55, the maximal relative error and the average relative error are of 9% and 2.4% respectively. Therefore, it is undoubtly that the scheme gives reasonable predictings when the equivalent diameter ratios are of 0.55, 0.65 as well as 0.75, and is proved valuable for application. The deviation is a bit high when the equivalent diameter ratio is of 0.45, for the maximal relative error is approximately 17%, the average relative error is less than 3.7%.
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