Numerical simulation method for cavitation compressible flow shock wave dynamics

Abstract

The invention discloses a numerical simulation method for cavitation compressible flow shock wave dynamics and belongs to the field of numerical simulation of cavitation compressible flow and shock wave dynamics. A three-dimensional computing watershed based on three-dimensional geometric modeling software is established; a three-dimensional computing watershed mesh is divided based on mesh generation software; a cavitation compressible flow computational fluid dynamics model is established; an initial boundary condition is set to perform a three-dimensional computational domain flow field numerical computation; based on flow field post-processing software, the computational result is post-processed to obtain the unsteady evolution process of a multi-phase bubble structure. The numerical simulation method for cavitation compressible flow shock wave dynamics in the invention facilitates in-depth study of the cavitation physical mechanism, can be applied to the field of cavitation compressible flow and shock dynamics numerical simulation and solves related engineering problems. The cavitation compressible flow and shock dynamics numerical simulation engineering application area comprises hydraulic machinery, marine propellers, aviation turbo pump induction wheels, underwater supercavitation weapon applications.

Description

technical field [0001] The invention relates to a numerical simulation method for cavitation compressible flow shock wave dynamics research, belonging to the field of numerical simulation of cavitation compressible flow and shock wave dynamics. Background technique [0002] Cavitation occurs in the low-pressure area of ​​high-speed water flow. It is a complex multi-phase flow involving intense phase-to-phase mass, momentum and energy exchange, phase change and turbulence. The occurrence of cavitation will induce severe pressure pulsation, vibration and noise. An in-depth understanding of the cavitation mechanism is the prerequisite for effectively suppressing the occurrence of unfavorable cavitation and avoiding cavitation damage in engineering, which has important scientific significance and engineering value. Cavitation is characterized by the generation, aggregation, and collapse of vapor cavities of different scales, and has complex interactions between cavitation / cavit...

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Problems solved by technology

[0003] Cavitation flow is a highly compressible compressible multiphase flow with phase change. In cavitation numerical simulation, it is often based on the assumption of phase equilibrium and incompressibility. It is considered that the velocity, pressure and temperature of the vapor / liquid phase are balanced, and the The liquid density is constant, and the incompressible cavitation numerical simulation method can predict the cavitation instability phenomena such as the growth of attached cavitation, the generation and propulsion of back jet flow, the fracture of cavitation and the process of cavitation shedding. The phenomenon of compressibility, such as cavitation-induced pressure pulsation, pressure pulse, cavitation collapse, cavitation shock wave dynamics, etc., which involves the cavitation transient load problem concerned in engineering practice, can be accurately captured. Experiments show that: cavitation The fracture and shedding process has a back jet mechanism and a shock wave mechanism. The shock wave mechanism will lead to more violent unsteady characteristics, and the shock wave mechanism is closely related to the cavitation compressibility

On the other hand, there is a non-uniform and unstable phase transition process in the cavitation flow field. The coupling of phase transition and compressibility makes the cavitation mechanism more complex and poses greater challenges to numerical calculations.

Cavitation flow has the characteristics of high density ratio between vapor and liquid, and the difference in vapor-liquid compressibility is large. At the same time, the sound velocity distribution of cavitation flow field has the characteristics of large span, from 1450m / s in pure water to 3- 5m / s, the cavitation area can reach more than 10 Mach numbers, and the introduction of compressible fluid poses new challenges for the capture of vapor-liquid free interface

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