Showing papers on "Ohnesorge number published in 2004"
TL;DR: In this paper, the main and satellite droplets of a 1D Lee model were compared with those obtained by an augmented one-dimensional Lee model (Lopez-Herrera et al. 1999).
Abstract: Controlled charged capillary jet breakup of conducting liquids with different viscosities and applied voltages are experimentally analysed in this work. Careful measurements of droplets size and charge transported by the main and satellite droplets have been carried out. The experimental results are compared with those obtained by an augmented one-dimensional Lee model (Lopez-Herrera et al. (1999). Theory and experiments show a remarkable agreement, which validates the rather inexpensive one-dimensional models as suitable predicting tools for scientific and engineering applications from electrospraying to charged jet printing over other sophisticated, more expensive three-dimensional models. Our results show that satellite droplets tend to undergo Coulombic rupture even in the case of very moderate electrification levels when the Ohnesorge number is sufficiently large.
79 citations
TL;DR: In this paper, an experimental investigation has been conducted into the effect of fluid velocity and orifice size on the breakup patterns of liquid CO2 in water, as well as those for water in CO2.
Abstract: An experimental investigation has been conducted into the effect of fluid velocity and orifice size on the breakup patterns of liquid CO2 in water, as well as those for water in CO2. Under high-pressure and low-temperature conditions, the jet breakup patterns follow distinct Rayleigh, transitional, and spray modes. Droplet size distribution was determined in the different modes, with the spray mode producing the smallest droplets and the most uniform size distribution. The system appears to progress from transitional to spray mode when the Ohnesorge number is approximately 18 Re−1. Using this relationship, it is possible to predict the minimum injection rate necessary for spray mode at any injector diameter. Under hydrate-forming conditions, the jet breakup did not appear to be affected because breakup occurred faster than hydrate formation. However, injection into a confined space could promote droplet coalescence, resulting in a larger average drop size. These results can be used to control hydrate conversion in an ocean CO2 injection system and to ensure a large dispersion of injected CO2 during its sequestration in the ocean.
18 citations
TL;DR: The influences of fluid properties of a Newtonian fluid, such as surface tension and fluid viscosity, on micro-fluidic characteristics for a certain jetting speed in the deposition process via a numerical approach is discussed, which indicates the impingement process consists of four different phases.
3 citations
01 Jan 2004
TL;DR: In this paper, the consistent behavior of non-dimensional parameters on the formation and break up of large cylindrical droplets has been studied by direct numerical simulations (DNS) using a one-fluid model with a finite difference method and an advanced front tracking scheme.
Abstract: The consistent behavior of non-dimensional parameters on the formation and break up of large cylindrical droplets has been studied by direct numerical simulations (DNS). A one-fluid model with a finite difference method and an advanced front tracking scheme was employed to solve unsteady, incompressible, viscous, immiscible, multi-fluid, two-dimensional Navier-Stokes equations. This time dependent study allows investigation of evolution of the droplets in different cases. For moderate values of Atwood number (AT), increasing Eotvos number (Eo) explicitly increases the deformation rate in both phenomena. Otherwise, raising the Ohnesorge number (Oh) basically amplifies the viscous effects.Copyright © 2004 by ASME
1 citations