离心式喷嘴内流场特性的数值模拟

Numerical simulation of internal flow fleld of swirl nozzle

关键词:  离心喷嘴  二相流  数值仿真  流体动力模型

Key words:  Centrifugal injector  Two phase flow  Numerical simulation  Hydrodynamic model

摘要:

基于单流体模型及气液两相混合分数的概念,建立了离心式喷嘴内流场的数学模型,并进行了数值计算。计算结果给出了离心式喷嘴内部液膜与气涡共存的流场结构及气液交界面的几何形状。计算得到的壁面压力分布、出口处液膜内轴向速度分布以及雾角大小都与实验结果吻合的很好。与常用的跟踪气液界面的ALE方法相比,本文建立的数值模拟方法具有简单、计算量小和易于实现的特点。

Abstract:

Numerical simulation of the internal flow of a swirling nozzle is carried out by using the single-fluid model, in which the gas-liquid interface was distinguished by the two-phase mixture fraction. The structure of the flow field, which consists of liquid film and gas core, was obtained. The predicted results of the wall pressure distribution, axial velocity profiles at the outlet and the spray angle agreed well with the experimental datum. Compared with the ALE method, which is commonly used to track the gas-liquid interface, the numerical method in present work has the advantages of simplicity and lower computational cost for understanding of the flow properties in the swirling nozzle and improving of the nozzle design.