Impinging distance influence

Influence of impinging distance on the standard deviation of droplet size distribution... 

Neither the air flow rate, the volume of the drying chamber, nor the impinging distance affects the values of the heat transfer coefficient no significant influences of the diameter of the particles or the feeding schemes on the heat transfer coefficient were observed. 

The results on the influence of the impinging distance are shown in Fig. 7.17 as a plot of 77s versus the dimensionless impinging distance, S/d(). In the range tested the sulfur-removal efficiency decreases continuously as S/d() reduces. The most likely reason is that at smaller impinging distance the concentration of droplets in the impingement zone increases, giving enhanced collision between droplets and an increased tendency of the droplets to coalescence, thus reducing the interface area. On... 

The influences of the liquid and gas flow rates, the diameter of the absorption chamber, the distance between nozzles, and the flow configuration on absorption rate were studied by the researchers mentioned above. These will not be discussed in detail here because of the length limitation of the chapter for the details, the reader may refer to the original references as cited in the text above. It should be noted, however, that in all the investigations above, the data for mass transfer coefficients are always correlated with the gas and/or liquid flow rates, but not with the impinging velocity, m0, although the latter is the operation parameter extremely important in every impinging stream device. 

The study done by Stroud et al. [2] relates changes in burner configuration to changes in flame stability and the flame environment created above the burner for laminar, stoichiometric flame conditions incorporating the influence of crossflow resulting from impinging surface motion, which is a condition that is often seen in industry processes. As stated in Section 22.2.1, the optimal flame separation distance has been experimentally determined to be 1.25-2.25 mm [5] under conditions without impinging surface motion. Based on these results, one would expect that three or four typical ribbons between each row of ports would be optimal as each ribbon typically has a width of 0.5 mm. 

The consideration outlined above agrees with the assumption that substrates influence the structure formation of barnacle adhesive indirectly via properties that hold the barnacle base at a distance from the surface (e.g., fiber coatings, thick biofilm layers) or cause large interfacial gaps (e.g., PDMS coatings). These factors affect the concentration in the dispersion, and hence the position on the adsorption isotherm as compared to the micellar or hemi-micellar concentration, by impinging on the interfacial volume that needs to be filled with adhesive. 

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