Gas-liquid two-phase flow parameter measuring method based on double-differential pressure of Venturi tube

Abstract

The present invention discloses a gas-liquid two-phase flow parameter measuring method based on double-differential pressure of a Venturi tube. The method comprises the following steps of: (1) measuring differential pressure fluctuation signals of the Venturi tube in upward and downward inclination directions; (2) applying the empirical mode decomposition method to decompose the differential pressure fluctuation signals in two pressure tapping directions so as to obtain intrinsic mode functions and residual errors; (3) calculating relative energy of each intrinsic mode function; (4) rejecting noise components; (5) determining pseudo components according to threshold values of the relative energy; (6) calculating characteristic quantities according to the intrinsic mode functions, the residual errors and the pseudo components; (7) inputting the characteristic quantities into a neural network, and predicting void fraction, dryness fraction and total mass flow; and (8) calculating gas phase and liquid phase mass flows. The gas-liquid two-phase flow parameter measuring method has the beneficial effect that a plurality of parameters of two-phase flow can be predicted only according to two differential pressure signals of one Venturi tube without a gas-liquid separator. According to the gas-liquid two-phase flow parameter measuring method having a lot of detecting parameters, real-time performance is good, the device is simple, and implementation is easy. The method is suitable for measuring gas-liquid two-phase flow multi-parameters.

Description

technical field [0001] The invention belongs to the technical field of fluid measurement, and in particular relates to a gas-liquid two-phase flow parameter measurement method based on Venturi tube double differential pressure. Background technique [0002] Gas-liquid two-phase flow widely exists in petroleum, chemical, pharmaceutical, power and other industrial fields. The online detection of parameters such as void ratio, dryness, and flow rate is of great importance to the control, reliable operation and efficiency of gas-liquid two-phase flow systems. The significance of has been an important research content in the field of two-phase flow for a long time. For example, in the petroleum industry, when oil and gas are measured, the oil, gas and water are first separated, and then transported and measured in phases through multiple pipelines. The oil and gas separation equipment used in this metering method is bulky and expensive. If one pipeline can be used for multi-phas...

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Problems solved by technology

When the gas-liquid two-phase flows through the throttling element, the differential pressure fluctuates greatly, which leads to the low prediction accuracy of the above mathematical model

[0007] At present, the differential pressure two-phase flow parameter measurement technology uses a local single differential pressure signal to calculate the parameters of the two-phase flow such as void ratio, dryness and flow rate, but the local single differential pressure signal cannot fully and accurately reflect the fluid in the pipeline. The distribution and flow characteristics of

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