A high-density-ratio gas-liquid phase change mixed LBM numerical model and application

Abstract

The invention belongs to the technical field of computer simulation, and discloses a high-density-ratio gas-liquid phase change mixed LBM numerical model and application. In order to overcome the defects that interface parameters of a traditional single-component pseudo potential phase change model cannot be independently adjusted and controlled in phase change simulation, and the superheat degreein bubbles in the boiling process cannot be correctly reflected, on the basis of a single-component multi-relaxation pseudo potential grid Boltzmann model, a gas-liquid phase change model is established by adopting an interface pressure driving phase change mode to couple a heat transfer equation. By simulating the liquid level evaporation phenomenon, the correctness and the simulation precisionof the model are verified. The model is adopted to simulate the temperature distribution and the interface change in a single bubble growth process. Compared with an existing phase-change boiling model, the simulated gas-liquid two-phase density ratio is greatly improved, the two-phase interface parameters can be independently controlled by adopting the model, the change of the superheat degree inthe bubbles in the growth process of the bubbles can be reflected, and the phase-change boiling model is more consistent with the bubble dynamics theory.

Description

technical field [0001] The invention belongs to the technical field of computer simulation, and in particular relates to a mixed LBM numerical model of gas-liquid phase transition with a large density ratio and its application. Background technique [0002] At present, the commonly used existing technologies in the industry are as follows: boiling heat transfer is widely used in nuclear energy, aerospace, materials and other technical fields, as well as in energy, power, petroleum, chemical industry, metallurgy, refrigeration food, papermaking and other industries. Due to the complex mechanism of boiling phenomenon, it is difficult to obtain accurate results by using traditional experimental and theoretical methods. With the development of computer technology, the numerical calculation of fluid has been fully developed. Among them, the lattice Boltzmann method is a mesoscopic simulation method based on statistical thermodynamics developed in recent decades. Due to its good ...

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Problems solved by technology

Bubble superheat is an important condition for bubble nucleation, which directly affects the mechanism of bubble growth and nucleation. Neglecting the superheat will cause a big difference between the simulated bubble growth and nucleation and the actual one.

[0004] To sum up, the problems existing in the existing technology are: the existing models are difficult to simulate the actual gas-liquid phase change phenomenon; the phase change model cannot be independently controlled during the simulation calculation process, and it is difficult to obtain the change rule; it is difficult to obtain an accurate Numerical results; difficult to reflect bubble growth superheat

In particular, although the existing thermodynamic theory of the bubble nucleation mechanism at the micro scale is relatively complete, it is still difficult to accurately predict the actual boiling process.

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