Numerical Analysis of Droplet Flow Regime in Gas-Liquid Two-Phase Flow using Particle Method

气液两相流中液滴流态的粒子法数值分析

• 批准号: 13650167
• 负责人: KOSHIZUKA Seiichi
• 金额: $ 2.62万
• 依托单位: The University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2001
• 资助国家: 日本
• 起止时间: 2001 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13650167/
• 关键词: Gas-liquid two-phase flow; Droplet; Surface tension; Numerical analysis; Particle method; Critical Weber number; Interfacial area; MPS method; 気液三相流; ドライアウト; 沸騰遷移; 液滴の分裂; 液滴流; 臨界ウエーバー数

Two-fluid model has been used for gas-liquid two-phase flow analysis. Governing equations of gas and liquid phases are simultaneously solved with correlations expressing interfacial interactions. These correlations are obtained by experiments. Numerical analysis is difficult for them. In particular, interfacial area is an important parameter to determine the interactions. Grids are not necessary in particle method, so that fragmentation and coalescence of fluids as well as large deformation of interfaces can be analyzed. In the present study, the critical Weber number by which the interfacial area is evaluated in the droplet flow regime is analyzed by the particle method.The particle method used here is MPS (Moving Particle Semi-implicit) method which has been developed by the present researcher. A new model for surface tension is developed to analyze single droplet behavior. Vibration of a square droplet is calculated and the oscillating period agrees with that of the analytical solution. Flow around a droplet is calculated and the pressure distribution on the droplet agrees with those of the past studies. Droplet breakup is driven by the pressure distribution and suppressed by surface tension. Both processes are verified. It is also clarified that more than 100 particles are necessary to analyze the droplet behavior accurately.It is known that the droplet breakup is governed by a non-dimensional number called Weber number, which is the ratio of the driving force to the suppressing force. Critical Weber number gives the limit of droplet breakup. The breakup does not occur when the Weber number is below the critical value. The droplet behavior is calculated for various Weber numbers using the MPS method. The results show that the critical Weber number is 13. This agrees with experimental data. Therefore, it is concluded that the critical Weber number is successfully analyzed by the MPS method.

气液两相流动分析采用双流体模型。用描述界面相互作用的关联式同时求解气相和液体的控制方程。这些关联式是通过实验获得的。数值分析对他们来说是困难的。其中，界面面积是决定相互作用的重要参数。粒子法不需要网格，因此可以分析流体的破碎和聚合以及界面的大变形。本文用质点方法分析了液滴流动过程中计算界面面积的临界韦伯数，所用的质点方法是本文提出的移动粒子半隐式方法。发展了一种新的表面张力模型来分析单个液滴的行为。计算了正方形液滴的振动，其振荡周期与解析解符合较好。对液滴周围的流动进行了计算，液滴上的压力分布与以往的研究结果一致。液滴的破碎由压力分布驱动，表面张力抑制。这两个过程都经过了验证。此外，还阐明了要准确分析液滴的行为需要100多个粒子。众所周知，液滴的破碎由一个称为韦伯数的无量纲数决定，韦伯数是驱动力与抑制力的比率。临界韦伯数给出了液滴破碎的极限。当韦伯数低于临界值时，不会发生破裂。用MPS方法计算了不同韦伯数下的液滴行为。结果表明，临界韦伯数为13，这与实验数据相吻合。因此，MPS方法成功地分析了临界韦伯数。

项目成果

K.Shibata: "Numerical Analysis of Jet Breakup Behavior using Particle Method"Proc. 5th JSME-KSME Fluids Engineering Conference. 1144-1148 (2002)

K.Shibata：“使用粒子法对射流破碎行为进行数值分析”Proc。

S. Koshizuka: "Particle Method for Incompressible Flow with Free Surface"Proc. ASME 2002 Fluids Engineering Division Summer Meeting (FEDSM'02). FEDSM2002-31154. (2002)

S. Koshizuka：“自由表面不可压缩流动的粒子方法”Proc。

S.Koshizuka: "Numerical Analysis of Large Deformation of Free Surface using Particle Method"Proc. 8th Symposium on Nonlinear and Free-Surface Flows. 41-44 (2002)

S.Koshizuka：“使用粒子法对自由表面大变形进行数值分析”Proc。

K.Nomura, S.Koshizuka, Y.Oka, H.Obata: "Numerical Analysis of Droplet Breakup Behavior using Particle Method"J. Nucl. Sci. Technol.. 38(12). 1057-1064 (2001)

K.Nomura、S.Koshizuka、Y.Oka、H.Obata：“使用粒子法对液滴破裂行为进行数值分析”J。

越塚誠一: "粒子法による流れの数値解析"ながれ. 21. 230-239 (2002)

Seiichi Koshizuka：“使用粒子法进行流动的数值分析”Nagare 21. 230-239 (2002)。