Abstract: A forward and reverse bidirectional flow rate measurement method for a subsea chemical agent injection device is provided. The device includes a device body, a flow channel is formed inside the device body, the device body includes an agent input connector, a pressure reduction member, a needle valve assembly, and an agent output connector that are sequentially communicated through the flow channel; and the method is implemented by: calibrating forward and reverse flow of agents at different openings and flow rates, then obtaining differential pressures before and after the agents flow through the needle value assembly; fitting relationships between the flow rates and the differential pressures at different openings to obtain a plurality of arrays of opening-flow coefficients; then fitting relationships between the flow coefficients and the needle valve openings to establish a formula for the flow rate and the opening-differential pressure, and finally performing the measurement in real time.

Abstract: A metering method based on gas volume fraction fitting for wet natural gas is provided. The method includes fitting relationships between a gas Froude number and Venturi differential pressure and Venturi pressure loss with known data to obtain a gas Froude number calculation formula; dividing the known data according to a size of the gas Froude number; fitting relationships between a gas volume fraction and the Venturi differential pressure and the Venturi pressure loss in sections to obtain a piecewise gas volume fraction calculation formula under different gas Froude numbers; and acquiring, on the basis of the gas Froude number calculation formula and the piecewise gas volume fraction calculation formula, some necessary real-time data to calculate a real-time flow rate of the wet gas. The method avoids the use of a ray flow meter. The advantages of the method include accurate metering, small errors and no radioactive pollution.

Abstract: A metering method based on converted slip ratio fitting for wet natural gas is provided. The method includes fitting relationships between a gas Froude number and Venturi differential pressure and Venturi pressure loss with known data to obtain a gas Froude number calculation formula; dividing the known data according to a size of the gas Froude number, and performing piecewise fitting to obtain a piecewise converted slip ratio calculation formula under different gas Froude numbers; performing fitting on the dryness fraction and the converted slip ratio calculation formula; and acquiring, on the basis of the gas Froude number calculation formula, the converted slip ratio calculation formula, an overrated factor calculation formula and a dryness fraction calculation formula, some necessary real-time data to calculate a real-time flow rate of the wet gas. The method avoids using a ray flow meter and has advantages that include accurate metering and no radioactive pollution.

Abstract: A ray transceiving system of an underwater flowmeter includes a flowmeter body. A fluid metering channel, a transmitting window, and a probing window are arranged on the flowmeter body. The transmitting window and the probing window are respectively in communication with the fluid metering channel, and each of the transmitting window and the probing window is provided with a titanium alloy isolation seat and a beryllium pad. Titanium alloy is used to seal the fluid metering channel, the titanium alloy and the beryllium pad are combined to bear pressure, and the beryllium pad is used to reduce absorption of gamma rays. A deduction metering method of the underwater flowmeter partially deducts the gamma count rate distortion caused by the Compton scattering effect, and calculates the content of each phase in a three-phase mixed flow to improve the metering accuracy of the three-phase content of oil, gas, and water.

Abstract: Provided are a steam flow metering device and a metering method therefor. The device mainly comprises a mono-energetic gamma sensor (5), a Venturi-type flowmeter (6), a temperature transmitter (2), a pressure transmitter (3), a pipe connection section at the steam-inlet (1), and a pipe connection section at the steam-outlet (7), the function thereof being to measure the quantity of saturated water and saturated steam within the steam effectively and in real time.