CN-122021459-A - Flow channel structure optimization method and system for non-Newtonian fluid collector

CN122021459ACN 122021459 ACN122021459 ACN 122021459ACN-122021459-A

Abstract

The invention discloses a method and a system for optimizing a flow channel structure of a non-Newtonian fluid distribution and aggregation device, and belongs to the fields of petroleum engineering oil extraction equipment design and computational fluid mechanics. The method comprises the steps of obtaining a critical shear rate threshold value of mechanical degradation of fluid based on rheological parameters of target non-Newtonian fluid, constructing a dynamic viscosity correction model containing damage factors based on the shear history and the critical shear rate threshold value of fluid micro-clusters, constructing a parameterized geometric model of a flow channel of a polymer distributor, setting key parameters of a flow channel structure of the polymer distributor, introducing the damage factors and constructing a dynamic viscosity correction model of space-time coupling, realizing real-time bidirectional coupling of a flow field and viscosity attenuation by solving a damage transport equation, and successfully characterizing the shear history effect of the fluid.

Inventors

ZHAO QIUYANG
LI TENGYU
WANG YECHUN
DAI JIAYI
LU JUNJIE
An Pengxu

Assignees

西安交通大学

Dates

Publication Date: 20260512
Application Date: 20260331

Claims (10)

1. The optimization method of the flow channel structure of the non-Newtonian fluid collector is characterized by comprising the following steps of: Acquiring a critical shear rate threshold at which mechanical degradation of the fluid occurs based on rheological parameters of the target non-newtonian fluid; constructing a dynamic viscosity correction model containing damage factors based on the shearing history of the fluid micro-clusters and a critical shearing rate threshold; constructing a parameterized geometric model of the flow channel of the collector, and setting key parameters of the flow channel structure of the collector; And carrying out numerical simulation on the flow field under different geometric parameter combinations by using the dynamic viscosity correction model and the parameterized geometric model, and calculating the viscosity retention rate and the mixed pressure drop at the outlet of the flow channel so as to obtain the geometric parameter combination which meets the preset injection pressure drop requirement and maximizes the viscosity retention rate as the optimal flow channel structural parameter.
2. The method for optimizing the flow channel structure of a non-Newtonian fluid collector according to claim 1, wherein the method is characterized in that based on rheological parameters of a target non-Newtonian fluid, steady-state viscosity of the fluid in a preset shear rate range is measured by using a rotary rheometer, and a critical shear rate threshold value for mechanical degradation of the fluid is obtained by fitting a Carreau-Yasuda model and identifying a deviation point of an experimental viscosity value and a model predicted value in a high shear zone.
3. The method for optimizing flow channel structure of non-Newtonian fluid collector as claimed in claim 1, wherein the dynamic viscosity correction model is a space-time coupled damage rheological model, and the scalar damage factor is introduced Characterizing the accumulated degradation degree of fluid micro-groups, setting the equivalent viscosity of the fluid From the base rheological viscosity And infinite shear viscosity Weighted by impairment factors, i.e. Wherein the damage factor Obtained by solving scalar transport equations containing convection terms, diffusion terms, and damage source terms to reflect the cumulative effect of shear history on viscosity.
4. The method for optimizing flow channel structure of non-Newtonian fluid dispenser according to claim 1, wherein the key parameters at least comprise a throttle aperture ratio Diffusion angle of expansion section And the length ratio of the upstream and downstream molded lines of the throttle unit.
5. The method for optimizing the flow channel structure of a non-Newtonian fluid collector according to claim 1, wherein a computational fluid dynamics solver is used for calculating flow field speed and shear rate, a custom function is set for reading local shear rate in real time, and when the local shear rate exceeds a critical shear rate threshold, a scalar transport equation of a damage source term is triggered to calculate and update damage factors so as to update equivalent viscosity of grid units.
6. The method of optimizing flow path structure of a non-Newtonian fluid dispenser of claim 5, wherein the optimal balance point is found between the abrupt rise of pressure drop and the cliff-like drop of viscosity retention by parametric scan to determine the optimal throttle aperture ratio Diffusion angle of expansion section And the proportion of the line length.
7. The flow channel structure optimization system of the non-Newtonian fluid collector is characterized by comprising a pretreatment module, a correction module, a geometric parameter module and an optimization module; the pretreatment module is used for acquiring a critical shear rate threshold value of mechanical degradation of the fluid based on rheological parameters of the target non-Newtonian fluid; a correction module that constructs a composition comprising a damage factor based on a shear history and a critical shear rate threshold of the fluid micro-clusters Dynamic viscosity correction model of (a); the geometric parameter module is used for constructing a parameterized geometric model of the flow channel of the collector and setting key parameters of the flow channel structure of the collector; And the optimization module is used for carrying out numerical simulation on the flow field under different geometric parameter combinations by utilizing the dynamic viscosity correction model and the parameterized geometric model, and calculating the viscosity retention rate and the mixed pressure drop at the outlet of the flow channel so as to obtain the geometric parameter combination which meets the preset injection pressure drop requirement and maximizes the viscosity retention rate as the optimal flow channel structural parameter.
8. The method for optimizing a flow channel structure of a non-Newtonian fluid dispenser according to claim 7, wherein a steady-state viscosity of the fluid in a preset shear rate range is measured by using a rotational rheometer based on rheological parameters of a target non-Newtonian fluid, and a critical shear rate threshold for mechanical degradation of the fluid is obtained by fitting a Carreau-Yasuda model and identifying a deviation point of an experimental viscosity value from a model predicted value in a high shear region.
9. The flow channel structure optimization system of non-Newtonian fluid collector as claimed in claim 7, wherein the dynamic viscosity correction model is a space-time coupled damage rheology model, and wherein a scalar damage factor is introduced Characterizing the accumulated degradation degree of fluid micro-groups, setting the equivalent viscosity of the fluid From the base rheological viscosity And infinite shear viscosity Weighted by impairment factors, i.e. Wherein the damage factor Obtained by solving scalar transport equations containing convection terms, diffusion terms, and damage source terms to reflect the cumulative effect of shear history on viscosity.
10. The flow channel structure optimization system of a non-Newtonian fluid dispenser of claim 7, wherein said key parameters comprise at least a throttle aperture ratio Diffusion angle of expansion section And the length ratio of the upstream and downstream molded lines of the throttle unit.

Description

Flow channel structure optimization method and system for non-Newtonian fluid collector Technical Field The invention relates to the technical field of petroleum engineering oil extraction equipment design and computational fluid mechanics, in particular to a method and a system for optimizing a flow channel structure of a non-Newtonian fluid polymer distributor. Background In the polymer flooding technology for improving oil recovery ratio (EOR), a polymer distributor is a key device for realizing online mixing and layered injection distribution of high-concentration polymer mother liquor and high-pressure water. The core function of the device is to create a sufficient pressure drop through the internal throttling unit to meet the injection pressure requirements of the different injection intervals. However, the design and application of existing compounders are subject to significant contradiction between high restriction pressure drop and low viscosity loss, mechanical degradation is severe, and in order to create the megapascal pressure drop required for engineering, the fluid must flow through a narrow restriction passage, resulting in extremely high local shear rates (typically exceeding 10 4s-1). Under the high shearing action, long-chain molecules of a polymer (such as polyacrylamide) are easy to mechanically degrade, irreversible viscosity loss is caused, oil displacement efficiency is seriously affected, the distortion problem usually occurs in the existing simulation model, and a traditional flow field simulation usually adopts a power law model or a static Carreau model which only depends on local shearing rate. Prior studies have shown that polymer degradation depends not only on instantaneous shear rate (space factor) but also on its residence time in the high shear zone and on the historical cumulative effect (time factor). The traditional model can not capture accumulated damage caused by space-time coupling, so that the prediction error of the outlet viscosity is often more than 15%, the current structural design lacks theoretical support, and the current throttling unit mostly adopts a symmetrical structure or a simple scaling tube design. The simple streamline design can reduce shearing but has insufficient pressure drop, and the simple linear design can raise pressure drop but can aggravate degradation. An optimized structure capable of quantitatively balancing a shear flow field and energy dissipation is lacking at present. Disclosure of Invention The invention aims to provide a flow channel structure optimization method and system for a non-Newtonian fluid collector, which solve the problems of contradiction between pressure drop and adhesion retention, low prediction precision of a simulation model and no quantitative theoretical support of structural design in the prior art. In order to achieve the above purpose, the technical scheme adopted by the invention is as follows: a flow channel structure optimization method of a non-Newtonian fluid collector comprises the following steps: S1, acquiring a critical shear rate threshold value of mechanical degradation of a fluid based on rheological parameters of a target non-Newtonian fluid; S2, constructing a dynamic viscosity correction model containing damage factors based on the shearing history of the fluid micro-clusters and a critical shearing rate threshold; s3, constructing a parameterized geometric model of the flow channel of the collector, and setting key parameters of the flow channel structure of the collector; s4, carrying out numerical simulation on the flow field under different geometric parameter combinations by using the dynamic viscosity correction model and the parameterized geometric model, and calculating the viscosity retention rate and the mixed pressure drop at the outlet of the flow channel so as to obtain the geometric parameter combination which meets the preset injection pressure drop requirement and maximizes the viscosity retention rate as the optimal flow channel structural parameter. Preferably, based on rheological parameters of the target non-Newtonian fluid, measuring steady-state viscosity of the fluid within a preset shear rate range by using a rotary rheometer, and obtaining a critical shear rate threshold value of mechanical degradation of the fluid by fitting a Carreau-Yasuda model and identifying a deviation point of an experimental viscosity value and a model predicted value in a high-shear region. Preferably, the dynamic viscosity correction model is a space-time coupled damage rheological model, and specifically, scalar damage factors are introducedCharacterizing the accumulated degradation degree of fluid micro-groups, setting the equivalent viscosity of the fluidFrom the base rheological viscosityAnd infinite shear viscosityWeighted by impairment factors, i.e.Wherein the damage factorObtained by solving scalar transport equations containing convection terms, diffusion terms, and damage source