Pipe Liquid-Film Roughness for Low-Loading Pressure Drop
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Solution Overview
Problem
Current techniques for predicting pressure drop in multiphase flows, particularly in low-liquid-loading conditions in pipelines, are inaccurate, leading to inefficiencies and safety concerns in oil and gas transportation.
Innovation Solution
A method and system that determine pressure drop by calculating effective roughness due to viscosity and surface tension of thin liquid films in pipes, using dimensional analysis and experimental data, to improve modeling of multiphase flows and pressure drop estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If current prediction techniques are used for pressure drop in multiphase flows, then the modeling process is simple, but the accuracy of pressure drop estimation is poor
Solution Approach 1:
The patent transforms the complex multiphase flow problem into an equivalent single-phase flow problem by introducing an effective roughness parameter that captures the combined effects of liquid film viscosity and surface tension. This parameter transformation allows using simple single-phase flow equations while achieving accurate multiphase flow predictions, resolving the contradiction between model simplicity and prediction accuracy.
Solution Approach 2:
The patent introduces an intermediary effective roughness parameter that mediates between the complex multiphase flow characteristics and the simple single-phase flow models. This intermediary parameter encapsulates the complex interactions of liquid films, viscosity, and surface tension, allowing accurate predictions without requiring complex multiphase modeling.
2Reliability
If unrealistically large friction parameters are applied to compensate for model inaccuracies, then the model output better reflects actual pressure drop, but the results become inaccurate and reduce operational efficiency and safety
Solution Approach 1:
The patent derives a physically-based effective roughness parameter that changes with liquid film thickness, viscosity, and surface tension characteristics. This dynamically changing parameter replaces the static, unrealistically large friction parameters previously used, providing both model reliability and prediction accuracy simultaneously.
3Measurement precision
If the influence of thin liquid films on pipe roughness is not accounted for, then the modeling is simpler, but the pressure drop estimation is inaccurate
Solution Approach 1:
The patent accounts for thin liquid film effects by transforming them into an effective roughness parameter that can be incorporated into standard single-phase flow equations. This approach captures the complex liquid film influences without requiring complex multiphase flow models, achieving accurate pressure drop estimation with minimal added complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The approach provides a more accurate estimation of pressure drops in multiphase flows, enhancing the design, operation, and safety of fluid transport systems by accounting for the influence of thin liquid films on pipe roughness and flow characteristics.
Implementation Method 1
determining an effective roughness in a pipe due to a liquid film in the pipe based on a viscosity of the liquid film
Implementation Method 2
determining an effective roughness in a pipe due to a liquid film in the pipe based on a surface tension of the liquid film
Data Source
Figure 1
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Figure 4A~4B
AI summary
Systems, methods, and computer-readable media that improve flow of a multiphase mixture in a fluid transport system by determining pressure drop of low-liquid loading flows are provided. The method includes obtaining physical dimensions of a pipe that transports a multiphase flow. The method also includes obtaining physical parameters of the multiphase flow in the pipe. The method further includes determining an effective roughness of a liquid film of the multiphase flow on an interior wall of the pipe using the physical dimensions of the pipe and the physical parameters of the multiphase flow. Additionally, the method includes determining a pressure drop in the pipe using the effective roughness of the liquid film. Moreover, the method includes determining operating parameters of the system based on the pressure drop in the pipe.