Viscosity spray formation effects

Effects of Fuel Viscosity and Pressure on Spray Formation. Atomizer is Delavan 90A, 2 gph and Fuel is No. 6 Oil. 

While fuel viscosity variations were large and had a dominant effect on spray formation, differences between SRC-II and No. 2 fuel oil are also consistent with surface tension and liquid density differences. 

Current breakup models need to be extended to encompass the effects of liquid distortion, ligament and membrane formation, and stretching on the atomization process. The effects of nozzle internal flows and shear stresses due to gas viscosity on liquid breakup processes need to be ascertained. Experimental measurements and theoretical analyses are required to explore the mechanisms of breakup of liquid jets and sheets in dense (thick) spray regime. 

The highly viscous spray fluids used in pesticide application have been either water-in-oil emulsions or solutions of macromolecules both systems are non-Newtonian since their viscosity varies with the applied shear. While a viscosity parameter which is suitable for studies on drop formation was subsequently devised for such systems (II), it was necessary to use Newtonian liquids in the initial studies on the effect of viscosity on drop size. Sugar solutions behave as Newtonian liquids and provide a suitable means of varying viscosity over a wide range. These were prepared from a commercially available syrup by dilution with distilled water 1% w/v of a black dye (Nigrosine G140) was added to each solution to render the spray drops visible for sizing. 

Physical interferences are due to the effects of the sample solution on aerosol formation within the spray chamber. The formation of an aerosol is dependent upon the surface tension, density and viscosity of the sample solution. This type of interference can be controlled by the matrix matching of sample and standard solutions, i.e. add the same sample components to the standard solution, but without the metal of interest. If this is not possible, it is then necessary to use the method of standard additions (Box 27.3). 

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