Highlight May 2007: Geometrical Dependent Droplet Generation in Head-on Devices

Precise droplet creation and control is a prerequisite condition to realize the full potential of two-phase flow. By using head-on devices (see figure 1), we observed that at low flow rates (10^-3~10^-2microL/min) the droplet size was exclusively determined by device geometry and independent of flow rate and flow ratio (see figure2), a phenomenon never observed before.

Figure 1. Left: Scheme of chip design of head-on devices. Right: Images of droplet generation in head-on devices: The water phase is 0.01M sodium dodecylsulfate+0.01 fluorescein sodium salt in DI water which solution fluoresces and is shown in white color. The oil phase is hexadecane shown in black color. The oil to water phase flow ratios Qo/Qw are 2.5 (top: Qo=0.005microL/min and Qw=0.0125microL/min) and 0.4(bottom: Qo=0.0125microL/min and Qo=0.005micro/min), respectively.

Figure 2. Left: Droplet size as a function of flow rate in the head-on devices at three different restriction channel widths (Qo/Qw=1.0). Right: Droplet size as a function of the restriction channel width at three different flow ratios.

This work is part of publication in Proceedings of microTAS 2007 Conference, October, Paris.

	Home > ... > News archive > Highlight May 2007: Geometrical Dependent Droplet Generation in Head-on Devices
Home News & Highlights People Vacancies Research Education & Assignments Publications Intranet Internal Links External links Movies Sitemap Search	weblink \| News archive \| Archive Highlights \| Promotie film Ana Valero Highlight May 2007: Geometrical Dependent Droplet Generation in Head-on Devices Precise droplet creation and control is a prerequisite condition to realize the full potential of two-phase flow. By using head-on devices (see figure 1), we observed that at low flow rates (10^-3~10^-2microL/min) the droplet size was exclusively determined by device geometry and independent of flow rate and flow ratio (see figure2), a phenomenon never observed before. Figure 1. Left: Scheme of chip design of head-on devices. Right: Images of droplet generation in head-on devices: The water phase is 0.01M sodium dodecylsulfate+0.01 fluorescein sodium salt in DI water which solution fluoresces and is shown in white color. The oil phase is hexadecane shown in black color. The oil to water phase flow ratios Qo/Qw are 2.5 (top: Qo=0.005microL/min and Qw=0.0125microL/min) and 0.4(bottom: Qo=0.0125microL/min and Qo=0.005micro/min), respectively. Figure 2. Left: Droplet size as a function of flow rate in the head-on devices at three different restriction channel widths (Qo/Qw=1.0). Right: Droplet size as a function of the restriction channel width at three different flow ratios. This work is part of publication in Proceedings of microTAS 2007 Conference, October, Paris.