Cross hydrodynamic focusing

The AeroSizer, manufactured by Amherst Process Instmments Inc. (Hadley, Massachusetts), is equipped with a special device called the AeroDisperser for ensuring efficient dispersal of the powders to be inspected. The disperser and the measurement instmment are shown schematically in Figure 13. The aerosol particles to be characterized are sucked into the inspection zone which operates at a partial vacuum. As the air leaves the nozzle at near sonic velocities, the particles in the stream are accelerated across an inspection zone where they cross two laser beams. The time of flight between the two laser beams is used to deduce the size of the particles. The instmment is caUbrated with latex particles of known size. A stream of clean air confines the aerosol stream to the measurement zone. This technique is known as hydrodynamic focusing. A computer correlation estabUshes which peak in the second laser inspection matches the initiation of action from the first laser beam. The equipment can measure particles at a rate of 10,000/s. The output from the AeroSizer can either be displayed as a number count or a volume percentage count. 

Figure 2.45 Design of a multilamination mixer with hydrodynamic focusing (upper left) and flow pattern in such a mixer for a total volume flow of 10 ml h of water (lower left), taken from [141. The right side of the figure shows the orientation of liquid lamellae over a cross-section of the constriction for different Reynolds numbers [142].

Hydrodynamic Focusing Cross-Injection Mixing Most Relevant Citations... 

Mixer 32 [M 32] Hydrodynamic Focusing Cross-injection Micro Mixer... 

Figure 1.67 Hydrodynamic focusing mixing element with cross-like structure [112]...

Droplets are formed by shear stress or a pressure drop in an in-channel continuous platform. The two basic configurations for droplet formation are shown in Fig. 4. The cross-junction configuration is similar to that for hydrodynamic focusing. The carrier fluid enters the channel from the middle inlet, while the droplet liquids join from both sides (Fig. 4a). The T-junction configuration lets the droplet liquids join perpendicular to the carrier flow (Fig. 4b). The formation behavior of droplets depends on the capillary number, which represents the ratio between the friction force and the surface tension in a two-phase system ... 

FIGURE 19.4 Flow-focusing cross-junction configuration for droplet formation. The center fluid (liquid A) is hydrodynamically focused by the continuous phase (liquid B) within the small orifice. Viscous forces overcome interfacial tension with thread instability in the enclosed orifice producing monodisperse droplets as rapidly as kilohertz frequencies. 

We introduced the technique for measuring the weak interaction forces acting between two particles using the photon force measurement method. Compared with the previous typically used methods, such as cross-correlation analysis, this technique makes it possible to evaluate the interaction forces without a priori information, such as media viscosity, particle mass and size. In this chapter, we focused especially on the hydrodynamic force as the interaction between particles and measured the interaction force by the potential analysis method when changing the distance between particles. As a result, when the particles were dose to each other, the two-dimensional plots of the kinetic potentials for each particle were distorted in the diagonal direction due to the increase in the interaction force. From the results, we evaluated the interaction coeffidents and confirmed that the dependence of the... 

Previous workers have studied the influence of the ratio of the cross-section area of the downcomer to the riser [4,5], the reactor height [6,7], the gas-liquid separator configuration [8], and the distributor type and location [9]. All these affect the flow characteristics and mass transfer. Most previous works focus on global parameters, such as the liquid circulation velocity [10-13] and the average gas holdup in the riser [14-16]. Although much work has been carried out on EL-ALRs, the proper design and scale-up of an EL-ALR is still difficult because any variation in the physical properties of the gas or the liquid and the reactor structural feathers can have a considerable effect on the hydrodynamics... 

In Wolynes treatment Chh is identified as the Stokes friction and is assumed to be given by the Stokes law with the hydrodynamic radius equal to the crystallographic radius. A second approximation is to ignore the cross term (hs- Wolynes theory then focuses on the time dependence... 

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