Impingement flow

Localized erosion-corrosion caused by turbulence or impinging flow at certain points of the surface. In the majority of cases of impingement attack, a geometrical feature of the system results in turbulence at one or more parts of the surface. 

Glass Impinger, flow rate = 0.014 m /min. tractor mounted near breathing zone of driver. Samples collected from work zones of 4 mixer-loader applicators (F, G, H, I). 

This section describes selected mass transport correlations for laboratory devices such as the rotating disk and cylinder. These mass transport correlations may be used in order to establish the same mass transport conditions (diffusional boundary layer thicknesses) as those obtained in a pipe or under impinging flow. Essentially, the experimenter may vary the rotation rate and geometry of the cylinder or disk to dial in the same mass transport conditions as obtained in the field for pipes or impinging jets. The user should also verify that the same hydrodynamic conditions also exist through use of Reynolds numbers, as shown above. 

When, at a temperature T, the condition P 20 P02 s fulfilled, the impinging flow of oxygen can be neglected. Then, the deoxidation time td for a monolayer of oxide is simply given by (Laurent et al. 1988) (Figure 6.24) ... 

At temperatures above 5000 K, the plasma is very viscous, and hence the effective sample introduction into the plasma is difficult. The current carrying plasmas, especially, strongly resist the introduction of aerosol particles because of the cooling effect of the impinging flow. However, the mixing of plasma and sample aerosol with current free plasma jets is easier. 

It is impossible to generalize the effect of steam drying on product quality. Table 20.2 gives a summary of tests carried out at McGill University on batch drying of hand-sheets in a static apparatus in which the samples were dried under an impingement flow of superheated steam. Note that the effects are all positive relative to air drying or, at most, comparable. In Finland, similar tests on paper dried on a dynamic pilot-scale apparatus have yielded comparable results. 

Korger, M. and Krizek, F. 1966. Mass-transfer coefficients in impingement flow from slotted nozzles, Int. J. Heat Mass Transfer, 9 345-353. 

Y. Zhuang, C. F. Ma, M. Qin, Fxperrmental study on local heat transfer with liquid impingement flow in two-dimensional micro-channels. International Journal of Heat and Mass Transfer, 1997, 40, 4055-4059. 

The velocity profile of the impinging flow through the point A is assumed as... 

Centrifugal Microfluidics, Figure 2 A capillary barrier in made up of a geometrical constriction from the channel diameter oth to a narrow capillary of diameter ofcap hydrophobic barrier, the contact angles are cap > 90° > dr The capability to stop the flow up to a certain frequency threshold a> (15) is determined by the capillary pressure Ape (14) scaling with the curvature as well as the inertia of the impinging flow... 

As for the uptake of OH on H20(l), Hanson et al. (1992a) gave y > 3.5 x 10 for pure water at 275 K by the measurement using wetted wall flow tube reactor. Takami et al. (1998) obtained y = (4.2 2.8) x 10 for pure water at 293 K by the impinging flow method, and reported that the value decreases with gas-liquid contact time and increases by a factor of 2-3 for the acidic and alkaline water with pH = 1 and 11. They estimated that the accommodation coefficient a is close to unity by the simulation using the rate constant of OH in the aqueous phase and Henry s law constants, which agrees with the result of a = 0.83 (300 K) by molecular dynamics calculation by Roeselova et al. (2004). The recommended values of the lUPAC subcommittee and the NASA/JPL panel are a >0.1 and 0.02, respectively (Wallington et al. 2012 Sander et al. 2011). 

Figure 12 Schematic diagram of apparatus used to produce oriented material by impinging flow.

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