A research team led by Kim Sung Ri, a section head at the Faculty of Mechanical Science and Technology, has carried out a CFD simulation on a vertical turbine flowmeter with air and hydrogen and compared the meter factors. Then, they have conducted research on improving its starting characteristic in a low flowrate domain.
Generally, the meter factors of a turbine flowmeter for different densities of gases are different.
To fix this problem, they carried out a CFD simulation on a vertical turbine flowmeter that employs air and hydrogen as working media, and analyzed the effect of the density of gas on meter factors.
First, they created a geometrical model and mesh, and performed a CFD simulation by ANSYS Fluent using an SST κ-ω turbulence model. The result showed that as the density of air is much higher than hydrogen, the zero-load rotational speed of air is much higher than that of hydrogen for the same flowrates, and in contrast, the meter factor of air is smaller than that of hydrogen. It also showed that the meter factor of hydrogen had nonlinearity in a low flowrate domain, while the meter factor of air was almost constant over the whole flowrate domain.
Second, they carried out CFD simulations on vertical turbine flowmeters with 2 and 6 inlet channels, respectively, and analyzed the effect of the number of inlet channels on the starting characteristic. The result showed that in case of 2 channels, the zero-load rotational speed in a low flowrate domain was much higher than in case of 6 channels and the meter factor had linearity.
In conclusion, adjusting the area of an inlet channel is a good method for improving the performance of gas flowmeters, and in particular, this method is the most effective for measuring low-density gas in a low flowrate domain.
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