On the correlation of the primary breakup length with fuel temperature in pressure swirl nozzle

A Comprehensive Review on Emulsions and Emulsion Stability in Chemical and Energy Industries

“…[73] Similar to solid particle dispersion, [74] the emulsion droplets can stick on the wall of pore throats by straining capture, or they may be retained at the porous medium surface due to several forces such as capillary and/or shear forces (interception capture). [75] When the emulsion droplet size is larger than the pore size diameter, the droplets will be trapped in the pores and block the fluid flow. This phenomenon is known as straining capture.…”

“…As the pressure increases, they are forced to enter a smaller pore until the velocity reaches high enough to re-entrain the droplets. [75] Based on the Laplace equation, the capillary pressure is proportional to the interfacial forces and the difference between the mean drop curvatures of downstream and upstream sections. [18] Filtration theory is required to predict the effect of velocity on the squeezing phenomena.…”

“…At high capillary pressures, it was observed that the drop squeezes through pore constriction without snapping off, when the drop size to pore throat size ratio is approximately equal to one. [75] The second mechanism for strained drop break-up is hydrodynamical instabilities. When a less viscous phase penetrates through a trapped droplet with a higher viscosity, the droplet break-up may occur by fingering.…”

“…[54] Since emulsions are thermodynamically unstable dispersions, they tend to separate and settle to reduce the interfacial energy between the oil and water phases. [75] Due to the density difference in the dispersed and continuous phases, the droplets experience a gravitational force and a buoyancy force. The frictional drag force also opposes the gravitational force.…”

“…The balance of the forces is formulated as the Stokes's law to determine the settling rate, [86] as is given in Equation (9): Figure 7. Pore blocking mechanism by interception and straining (modified according to Rezaei and Firoozabadi [75] ).…”