火箭推进

为探究液气动量比对内混式直流气液喷嘴雾化特性的影响,采用基于Gerris的VOF方法和自适应加密算法,对不同液气动量比下的两液相孔内混式直流气液喷嘴雾化过程进行数值计算。结果表明:Gerris可以清晰地捕捉到射流柱从变形、弯曲到雾化为液滴的全过程细节特征,雾化过程图像与实验拍摄的基本吻合,获得液滴空间分布,计算得到的全场液滴SMD为50～60 μm。当液气动量比较小时,内混式直流气液喷嘴的射流不发生相撞,雾化机制为气动破碎。随着液气动量比的增加,两股射流破碎长度和穿透深度均增大,射流发生相撞,雾化机制为气动破碎和撞击破碎。

In order to research the effects of liquid-gas momentum ratio on atomization characteristics of internal mixing gas-liquid injector, the internal mixing gas liquid injector with two jet holes was numerically computed under various liquid-gas momentum ratio by the VOF method and adaptive mesh refinement algorithm based on Gerris.The results show that the characteristics of the whole spray process are captured accurately in Gerris, which consists of column distortion,bending and disintegrating into droplets.The computational results are basically in good agreement with the breakup process images in experiment.The spatial distributions of droplets were obtained and the droplets SMD of full flow field is 50～60 μm.When liquid-gas momentum ratio is small, the liquid jets of internal mixing gas liquid injector do not collide with each other, and the atomization mechanism is pneumatic atomization.With the increase of the liquid-gas momentum ratio, two liquid jets' breakup length and penetration depth are increased, and liquid jets collide, at that time atomization mechanism is pneumatic atomization and impact atomization.

引言
1 数学物理模型
2 计算结果与分析
3 结论

图1 四叉树空间离散例子<br/>Fig.1 Example of quadtree mesh discretization

图1 四叉树空间离散例子
Fig.1 Example of quadtree mesh discretization

图2 内混式直流气液喷嘴结构图<br/>Fig.2 The structure diagram of internal mixing gas-liquid injector

图2 内混式直流气液喷嘴结构图
Fig.2 The structure diagram of internal mixing gas-liquid injector

图3 内混式直流气液喷嘴立体图<br/>Fig.3 Stereogram of internal mixing gas-liquid injector

图3 内混式直流气液喷嘴立体图
Fig.3 Stereogram of internal mixing gas-liquid injector

图4 Box块离散方向的定义<br/>Fig.4 Definition for discrete direction of Box block

图4 Box块离散方向的定义
Fig.4 Definition for discrete direction of Box block

图5 计算域
Fig.5 Calculate domain

表1 边界条件
Tab.1 Boundary conditions

表2 物性参数表
Tab.2 Physical parameters

图6 喷嘴雾化实验系统<br/>Fig.6 Spray experiment system for injectors

图6 喷嘴雾化实验系统
Fig.6 Spray experiment system for injectors

图7 不同雾场形态的计算结果与实验结果对比<br/>Fig.7 Comparison of spray structure between the simulation results and experimental results

图7 不同雾场形态的计算结果与实验结果对比
Fig.7 Comparison of spray structure between the simulation results and experimental results

$图8 不同液气动量比的雾场结构和体积分数分布云图(Vg=68 m/s,改变Vl)<br/>Fig.8 Spray structure and volume fraction contours at various liquid-gas momentum ratio(Vg =68 m/s, Vl is changed)$

图8 不同液气动量比的雾场结构和体积分数分布云图(Vg=68 m/s,改变Vl)
Fig.8 Spray structure and volume fraction contours at various liquid-gas momentum ratio(Vg =68 m/s, Vl is changed)

$图9 不同液气动量比的雾场结构和体积分数分布云图(Vl=12.5 m/s,改变Vg)<br/>Fig.9 Spray structure and volume fraction contours at various liquid-gas momentum ratio(Vl =12.5 m/s, Vg is changed)$

图9 不同液气动量比的雾场结构和体积分数分布云图(Vl=12.5 m/s,改变Vg)
Fig.9 Spray structure and volume fraction contours at various liquid-gas momentum ratio(Vl =12.5 m/s, Vg is changed)

图10 不同工况的射流穿透深度<br/>Fig.10 The jet penetration depth at various cases

图10 不同工况的射流穿透深度
Fig.10 The jet penetration depth at various cases

图11 不同工况的射流破碎长度<br/>Fig.11 The jet breakup length at various cases

图11 不同工况的射流破碎长度
Fig.11 The jet breakup length at various cases

图12 不同工况的液滴SMD <br/>Fig.12 Droplet SMD at various cases

图12 不同工况的液滴SMD
Fig.12 Droplet SMD at various cases

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备注

引言

1 数学物理模型

2 计算结果与分析

3 结论

期刊信息