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CN-121997842-A - CFD fluid simulation-based reaction kettle stirring blade arrangement optimization method and system

CN121997842ACN 121997842 ACN121997842 ACN 121997842ACN-121997842-A

Abstract

The invention relates to the field of reaction kettle stirring blade arrangement optimization, and discloses a reaction kettle stirring blade arrangement optimization method and system based on CFD fluid simulation, wherein the method comprises the steps of obtaining reaction kettle structure and working condition data to perform long-time scale transient CFD simulation, separating a low-frequency flow field time sequence to obtain a precession grid field, constructing a precession voxel octree, performing paddle layer local vortex structure segmentation and time-frequency decomposition based on the precession voxel octree to obtain a paddle layer local vortex shedding modal set, constructing an interlayer coherent vortex map tree, establishing a stirring blade arrangement multi-objective optimization model based on the interlayer coherent vortex map tree to solve to obtain a candidate blade arrangement solution set, generating a stirring blade installation scheme, and performing high-fidelity verification simulation combination result to form an arrangement correction rule; the method solves the problem that the traditional steady-state CFD cannot catch low-frequency large-scale circulation precession, realizes the optimization of stirring blade arrangement, and improves the batch stability and the product consistency in the reaction process.

Inventors

  • Xu Nanliang

Assignees

  • 苏州微格纳米科技有限公司

Dates

Publication Date
20260508
Application Date
20260409

Claims (10)

  1. 1. CFD fluid simulation-based reaction kettle stirring blade arrangement optimization method is characterized by comprising the following steps of: Obtaining structural and working condition data of the reaction kettle, carrying out long-time scale transient CFD simulation, separating a low-frequency flow field time sequence, obtaining a precession grid field, and constructing a precession voxel octree based on the precession grid field; performing pitch-layer local vortex structure segmentation and time-frequency decomposition based on the precession voxel octree to obtain a pitch-layer local vortex shedding modal set, and constructing an interlayer coherent vortex map tree based on the pitch-layer local vortex shedding modal set; establishing a stirring paddle arrangement multi-objective optimization model based on an interlayer coherent vortex spectrum tree, solving to obtain a candidate paddle arrangement solution set, and extracting a paddle arrangement optimization parameter set from the candidate paddle arrangement solution set; Generating a stirring paddle installation scheme based on the paddle arrangement optimization parameter set, performing high-fidelity verification simulation, forming an arrangement correction rule by combining the verification simulation result, and outputting the final stirring paddle arrangement optimization method of the reaction kettle.
  2. 2. The optimization method for the arrangement of stirring paddles of a reaction kettle based on CFD fluid simulation according to claim 1, wherein the process of obtaining structural and working condition data of the reaction kettle, performing long-time-scale transient CFD simulation, separating a low-frequency flow field time sequence, obtaining a precession grid field, and constructing a precession voxel octree based on the precession grid field comprises the following steps: collecting structural data and working condition data of the reaction kettle and constructing a three-dimensional transient CFD simulation model; Performing long-time scale transient calculation based on the three-dimensional transient CFD simulation model and extracting an original flow field time sequence; Performing low-frequency separation filtering based on the original flow field time sequence to obtain a precession grid field; a precession voxel octree is constructed based on the precession mesh field.
  3. 3. The optimization method for the arrangement of stirring paddles of a reaction kettle based on CFD fluid simulation according to claim 2, wherein the process of performing low-frequency separation filtering to obtain a precession grid field based on the original flow field time sequence comprises the following steps: determining a cut-off frequency of the low-frequency separation filter; Performing a time-dimensional filtering on each grid cell in the original flow field time series; a precession grid field is constructed based on the low frequency velocity vector time series and the low frequency pressure scalar time series.
  4. 4. The optimization method for the arrangement of stirring paddles of a reaction kettle based on CFD fluid simulation according to claim 2, wherein the process for constructing a precession voxel octree based on a precession grid field comprises: Defining a root node bounding box of a precession voxel octree; Performing initial uniform division to generate an initial voxel grid; defining adaptive subdivision criteria; Performing adaptive recursive subdivision to generate a precession voxel octree; The leaf nodes of the precession voxel octree are supplemented with temporal statistical properties.
  5. 5. The optimization method for stirring blade arrangement of a reaction kettle based on CFD fluid simulation according to claim 1, wherein the process of performing the partial vortex structure segmentation and the time-frequency decomposition of the paddle layer based on the precession voxel octree to obtain a partial vortex shedding modal set of the paddle layer and constructing the interlayer coherent vortex map tree based on the partial vortex shedding modal set of the paddle layer comprises the following steps: Performing pitch space segmentation based on the precession voxel octree to obtain a pitch voxel subtree set; Performing time-frequency decomposition on each oar layer voxel subtree in the oar layer voxel subtree set to obtain a oar layer local vortex shedding modal set; And constructing an interlayer coherent vortex spectrum tree based on the paddle layer local vortex shedding modal set.
  6. 6. The optimization method for the arrangement of stirring paddles of a reaction kettle based on CFD fluid simulation according to claim 5, wherein the process of performing time-frequency decomposition on each of the subtrees of the voxel of the paddle layer to obtain the local vortex shedding modal set of the paddle layer comprises the following steps: Extracting a paddle layer local precession time sequence matrix from a paddle layer voxel subtree; performing eigen orthogonal decomposition on the paddle layer local precession time sequence matrix to obtain a paddle layer space mode matrix and a paddle layer time coefficient matrix; performing spectrum analysis on the pitch time coefficient matrix to obtain a pitch modal frequency vector and a pitch modal phase vector; screening to obtain a paddle layer dominant mode index set based on energy contribution; And constructing a paddle layer local vortex shedding modal set based on the paddle layer dominant modal index set.
  7. 7. The optimization method for the arrangement of stirring paddles of a reaction kettle based on CFD fluid simulation according to claim 5, wherein the process for constructing an interlayer coherent vortex pattern tree based on the local vortex shedding modal set of the paddle layer comprises the following steps: defining a node data structure of an interlayer coherent vortex spectrum tree; Calculating the coupling strength coefficient of the adjacent paddle layer mode pairs; judging critical interference marks and generating coupling nodes; and assembling an interlayer coherent vortex spectrum tree.
  8. 8. The method for optimizing the arrangement of stirring paddles in a reaction kettle based on CFD fluid simulation according to claim 1, wherein said process of extracting a paddle arrangement optimization parameter set from a candidate paddle arrangement solution set comprises: defining design variables and constraint boundaries for optimization of the stirring paddle arrangement; constructing a precession sensitivity evaluation function based on the interlayer coherent vortex spectrum tree; Constructing a multi-objective optimization model of stirring paddle arrangement; Solving a multi-objective optimization model of the stirring paddle arrangement to obtain a candidate paddle arrangement solution set; A blade placement optimization parameter set is extracted from the candidate blade placement solution set.
  9. 9. The optimization method for the arrangement of stirring paddles of a reaction kettle based on CFD fluid simulation according to claim 8, wherein the process for constructing the precession-sensitivity evaluation function based on the interlayer coherent vortex spectrum tree comprises the following steps: extracting coupling characteristic statistics from the interlayer coherent vortex spectrum tree; constructing a response surface agent model of the design variable and the coupling characteristic; a precession-sensitivity assessment function is defined.
  10. 10. A CFD fluid simulation based reactor stirring paddle arrangement optimization system for implementing the CFD fluid simulation based reactor stirring paddle arrangement optimization method of any one of claims 1-9, characterized in that the system comprises: The precession voxel octree construction module is used for acquiring structural and working condition data of the reaction kettle, carrying out long-time scale transient CFD simulation, separating a low-frequency flow field time sequence to obtain a precession grid field and constructing a precession voxel octree based on the precession grid field; The interlayer coherent vortex spectrum tree construction module is used for executing the segmentation and time-frequency decomposition of the local vortex structure of the oar layer based on the precession voxel octree to obtain a local vortex shedding modal set of the oar layer, and constructing an interlayer coherent vortex spectrum tree based on the local vortex shedding modal set of the oar layer; The stirring paddle arrangement multi-objective optimization module is used for establishing a stirring paddle arrangement multi-objective optimization model based on an interlayer coherent vortex spectrum tree, solving to obtain a candidate paddle arrangement solution set, and extracting a paddle arrangement optimization parameter set from the candidate paddle arrangement solution set; The stirring paddle installation scheme generation and verification module is used for generating a stirring paddle installation scheme based on the paddle arrangement optimization parameter set, performing high-fidelity verification simulation, forming an arrangement correction rule by combining the verification simulation result, and outputting a final reaction kettle stirring paddle arrangement optimization method.

Description

CFD fluid simulation-based reaction kettle stirring blade arrangement optimization method and system Technical Field The invention relates to the field of optimization of stirring blade arrangement of a reaction kettle, in particular to a method and a system for optimizing stirring blade arrangement of a reaction kettle based on CFD fluid simulation. Background The multi-layer stirring paddle reaction kettle is widely applied to chemical reaction and crystallization processes in the fields of chemical industry, medicine and the like. In the prior art, parameters such as the type, diameter, rotating speed, axial distance and the like of stirring paddles are optimized to shorten macroscopic mixing time or ensure that the average turbulent dissipation rate of the full kettle meets process requirements, and the design thought of the device is mainly developed around improving the overall mixing efficiency and flow uniformity. In the actual production process, operators find that for certain crystallization processes sensitive to local concentration variation, even if the macroscopic mixing time of a reaction kettle and the average turbulent dissipation rate of the whole kettle reach design standards, the problem of poor uniformity of particle size distribution of crystal products still occurs, and the problem is particularly shown that the size difference of crystal particles in the same batch exceeds the expected range. According to analysis, the phenomenon is caused by the fact that the arrangement phase of the multi-layer stirring paddles and interlayer fluid movement in the existing design are not sufficiently decoupled, and low-frequency large-scale periodic swing occurs in a flow field in a specific area in the reaction kettle. The steady state calculation based on the Reynolds average Navier-Stokes equation or the unsteady state calculation method only focusing on high-frequency turbulence pulsation are commonly used at present, and the low-frequency structural flow field oscillation is difficult to capture, so that the potential problem cannot be identified in the design stage. The swing of the flow field can cause the periodic change of a local fluid velocity field near the feed inlet, so that the local concentration distribution of reactants in the initial mixing stage fluctuates, thereby affecting the uniformity of crystal nucleation and growth, finally causing the reduction of the quality stability of the product and increasing the difficulty of the subsequent separation and purification process. Disclosure of Invention In order to overcome the defects in the prior art, the invention provides the following technical scheme: the CFD fluid simulation-based reaction kettle stirring blade arrangement optimization method comprises the following steps: Step S1, acquiring structural and working condition data of a reaction kettle, performing long-time scale transient CFD simulation, separating a low-frequency flow field time sequence to obtain a precession grid field, and constructing a precession voxel octree based on the precession grid field; S2, performing pitch-layer local vortex structure segmentation and time-frequency decomposition based on a precession voxel octree to obtain a pitch-layer local vortex shedding modal set, and constructing an interlayer coherent vortex map tree based on the pitch-layer local vortex shedding modal set; Step S3, a stirring paddle arrangement multi-objective optimization model is established based on an interlayer coherent vortex spectrum tree, a candidate paddle arrangement solution set is obtained through solving, and a paddle arrangement optimization parameter set is extracted from the candidate paddle arrangement solution set; And S4, generating a stirring paddle installation scheme based on the paddle arrangement optimization parameter set, performing high-fidelity verification simulation, forming an arrangement correction rule by combining the verification simulation result, and outputting the final stirring paddle arrangement optimization method of the reaction kettle. The method comprises the steps of obtaining reaction kettle structure and working condition data, carrying out long-time-scale transient CFD simulation, separating a low-frequency flow field time sequence, obtaining a precession grid field, and constructing a precession voxel octree based on the precession grid field, wherein the steps of S11 are that the reaction kettle structure data and the working condition data are collected, a three-dimensional transient CFD simulation model is constructed, S12 are that long-time-scale transient calculation is carried out based on the three-dimensional transient CFD simulation model, an original flow field time sequence is extracted, S13 are that low-frequency separation filtering is carried out based on the original flow field time sequence, and the precession voxel octree is constructed based on the precession grid field. Further, the process of performing