Investigation on the swirlmeter performance in low pressure wet gas flow

Wet gas flow is a subset of gas–liquid two-phase flow, and the swirlmeter has been used in wet gas flow metering more and more recently. The swirlmeter performance in low pressure wet gas flow was investigated. It is found that the entrained liquid present in a gas stream tends to induce a negative bias in the gas flow rate reading of swirlmeter comparing with equal gas flow rate. When the Lockhart-Martinelli parameter X, which is closely related to the liquid fraction, is bigger than a threshold value, the swirlmeter will not properly work due to the disappearing of vortex precession. It is also found that the liquid-induced gas flow rate reading errors of swirlmeter are dependent on X and the gas densiometric Froude number Frg. A correlation for swirlmeter in low pressure wet gas flow is proposed, and it corrects the liquid-induced gas flow rate errors to an accepted accuracy under the tested conditions. It implies that the swirlmeter with the proposed correlation and the known liquid fraction may be used to meter the gas flow rate in wet gas applications with a relatively low liquid fraction.