北京生物医学工程

数字PCR中微滴生成尺寸与频率的数值模拟

Numerical simulation of the size and frequency ofmicro-droplets in digital PCR

作者：张森冯继宏张弘高辛未

单位：北京工业大学生命科学与生物工程学院(北京100124)

分类号：R318.04

出版年·卷·期（页码）：2017·36·4（361-365）

摘要：

目的微滴合成是数字PCR中的关键技术，但其中两相流速与生成微滴大小和频率的关系尚不明确。本文采用VOF模型研究数字PCR系统中生成微滴的尺寸、频率与两相流速的关系。方法将氟化油作为连续相，反应液(水)作为离散相，通过求解整体的动量方程和各自相的体积分数连续方程来实现相与相间的界面追踪，模拟出微通道内两相的流动情况，对不同两相流速下微通道内微滴生成的尺寸和频率进行研究。结果在不同的流速条件下，微通道内会出现弹状流、滴状流和管状流3种流型。并且，对于弹状流和滴状流，随着连续相流速的增加，微液滴的生成尺寸减小，生成频率增加；而随着离散相流速的增加，微液滴的生成尺寸和频率都会增加。结论在滴状流状态下，当连续相流速为0.048~0.064m/s，并且离散相流速为0.016~0.032m/s时，可高效生成数字PCR微滴。

Objective Micro-droplets formation is one of key technologies in the digital PCR.However,the relationship between the two-phase flow rate and the size and frequency of produced micro-droplets is undeveloped.In this paper,we simulate this relationship with the volume of fluid (VOF) model in the digital PCR system.Methods We used fluorinated oil as the continuous phase and reactants (water) as the disperse phase.Through solving the momentum equation of the whole system and volume fraction equation,we monitored the profiles of produced droplets and simulated the two-phase flow in the crossing micro-channel.We mainly focused on the size and frequency of the produced droplets.Results Under different two-phase flow rates,there were three typical flow patterns:bubbly,slug and annular flow.Moreover,with the increasing of the continuous flow rate of slug flow and bubbly flow,the droplet size decreased and the frequency increased.And as the dispersed flow rate rising up,the size and the frequency of the produced micro-droplets increased accordingly.Conclusions Under slug flow,we can effectively produce micro-droplets for digital PCR when the continuous flow rate is at 0.048m/s to 0.064m/s and dispersed flow rate is at 0.016m/s to 0.032m/s,respectively.

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