Modelling method for bubbling fluidized bed based on random motion of bubbles and particles

Abstract

The invention discloses a modelling method for a bubbling fluidized bed based on random motion of bubbles and particles. The method comprises the steps that (1) statistics for particle motion rules of the bubbling fluidized bed computed by CFD-DEM is carried out, and a Markov chain random model of a particle phase is established; (2) image identification is carried out to an instant distribution map of the bubbling fluidized bed particles computed by the CFD-DEM, statistics is carried out to rules for generation, motion and growth of the bubbles, and a bubble random development model is established; and (3) a baseball cap model of bubble shapes is used to couple the particle-phase Markov course with the bubble random model, and a random model of the particle motion of the bubbling fluidized bed is established. The method disclosed by the invention has the advantages that the defect that a single particle-phase Markov course cannot reflect bubble information and influences of the information on the particle motion can be solved; and computation loads are greatly reduced, and a computation speed is increased on the premise of guarantee of accuracy of the bubbling fluidized bed particle motion.

Description

technical field [0001] The invention relates to a modeling method of a bubbling fluidized bed based on the random movement of bubbles and particles, and belongs to the technical field of computer numerical simulation of gas-solid two-phase flow. Background technique [0002] Bubbling fluidized beds have very high heat transfer and heat transfer rates, and are widely used in chemical, energy, food and pharmaceutical processing and other fields. The computer numerical simulation of the bubbling fluidized bed is helpful to the optimal design of the system and can greatly reduce the test cost. [0003] Traditional empirical and semi-empirical models (such as plug flow model and bubbling two-phase model) have high calculation efficiency and fast model response, but such models cannot provide detailed particle and bubble motion laws, and the calculation accuracy is very low. Currently popular numerical simulation methods based on computational fluid dynamics and particle dynamics...

AI Technical Summary

Problems solved by technology

The interaction between the gas-solid two phases in a bubbling fluidized bed is very strong, and the appearance of bubbles has an impact on the particle movement. When using the same method as applied to the pure particle system, the Markov chain stochastic model is applied to the bubbling In a fluidized bed system, only very macroscopic particle motion laws can be obtained, and the complex gas-solid two-phase flow pattern in the bed cannot be simulated.

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