Gas-liquid two-phase flow pattern nonlinear kinetic analysis method based on generalized composite multi-scale entropy

Abstract

The invention provides a gas-liquid two-phase flow pattern nonlinear kinetic analysis method based on generalized composite multi-scale entropy. The method comprises the following steps: firstly, carrying out an air-water-gas-liquid two-phase flow experiment, and collecting pressure difference fluctuation time sequences of three flow patterns; then performing generalized coarse graining processing according to the flow type differential pressure fluctuation time sequence, calculating entropy values of all coarse graining time sequences of different scale factors, averaging the entropy values under the same scale factor, obtaining generalized composite multi-scale entropy under different scales, and drawing an entropy value change trend chart of the generalized composite multi-scale entropy; and finally, according to the generalized composite multi-scale entropy change trend charts of different flow patterns, calculating the generalized composite multi-scale entropy growth rate, and obtaining generalized composite multi-scale entropy growth rate distribution of the three flow pattern pressure difference fluctuation time sequences, thereby realizing representation and identification of the flow patterns. The generalized composite multi-scale entropy in the invention can map the complexity of the gas-liquid two-phase flow, and has the characteristics of strong robustness, simple calculation and easy realization.

Description

technical field [0001] The invention belongs to the field of nonlinear dynamic analysis of gas-liquid two-phase flow patterns, and specifically uses generalized compound multi-scale entropy to process pressure difference fluctuation time series to realize nonlinear dynamic characterization and identification of gas-liquid two-phase flow patterns. Background technique [0002] Gas-liquid two-phase flow exists widely in nature and industrial production processes. Due to the influence of phase interface interaction and local relative motion between phases, the two-phase flow process shows obvious nonlinear and non-equilibrium characteristics. The flow pattern of two-phase flow is the macroscopic performance of the gas-liquid two-phase mixture in a confined space, while the analysis of nonlinear dynamic characteristics maps the complexity of the flow pattern of two-phase flow and the evolution law of the nonlinear flow process. Analytical methods based on theoretical models and ...

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Problems solved by technology

However, the current nonlinear time series analysis method based on entropy has the following two defects: First, the coarse-grained process based on meanization will cause the loss of dynamic information of the original time series on the high-order moments, making the calculated There is a deviation in the entropy value; secondly, the entropy value calculation is too dependent on the length of the time series, which makes the consistency and stability of the entropy value under high scale factors poor

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