An Investigation on the Diffusion of Momentum and Mass of Fuel in a Diesel Fuel Spray

Abstract

An investigation on the diesel fuel spray injected into stagnant ambient air in a chamber is reported in this paper. The objective of the investigation was to analyze the processes of diffusion of mass and velocity of the fuel in the fuel spray. The distribution of velocity and mass of the fuel showed similarity in the zone of established flow. Gaussian normal probability distribution for free jet was assumed by earlier workers, starting with Albertson, et al., for analyzing such a situation. However, it has been found that diesel fuel spray in a chamber necessitates modification of the model described and a modified model has been proposed herein. The Abramovich model is also compared with the experimental data. The ratio of εm/εm0 varied from 1.24 to 1.45 for the change of injection pressure from 100 to 200 atm. It is conclusively shown that mass diffuses faster than the momentum, the rate of diffusion increasing with the increase in the injection pressure. The proposed model gives good agreement with experimental results. The various parameters of the equations for depicting the fuel spray as a jet have been evaluated and tabulated.

Study of mass and momentum transfer in diesel sprays based on X-ray mass distribution measurements and on a theoretical derivation

“…The final zone (beyond ~3.5 mm) shows a good agreement with the results given by the theoretical model for a Sc value near 0.5. This value is lower than those observed by Prasad and Kar (1976), but it must be considered that their study was developed under quite different conditions (P in < 20 MPa, ϕ o > 0.4 mm, P back = 0.1 MPa). Furthermore, they found that Sc decreased as injection pressure got higher, which would imply that values lower than 0.7 could be expected under modern engine conditions, as it has been obtained in the current study.…”

“…Some authors use gas jet distributions as a first approximation. Experimental similarities between them have been always remarked by other researchers (Adler and Lyn 1969;Prasad and Kar 1976;Sinnamon et al 1980;Correas 1998;Desantes et al 2006a). Different expressions for radial profiles can be found in the literature (Abramovich 1963;Hinze 1975;Schlichting 1978;Spalding 1979;Sinnamon et al 1980).…”

“…Adler and Lyn (1969) proposed a study of sprays using a continuous model of a gas jet, stating that this was justified due to the similarity between gas jets and sprays from the point of view of basic mechanisms. Since then, many other researchers have followed this path, as for example Rife and Heywood (1974), who developed a model to predict spray behaviour based on the gas jet equation, or Prasad and Kar (1976), who 8 performed an investigation in order to analyse the processes of diffusion of mass and velocity, obtaining quantitative data for treating the diesel spray as a turbulent jet. These and many other investigations imply that many results from the literature concerning gas jets can be directly applicable to sprays.…”

“…Only Prasad and Kar (1976) gave a range of value of 0.7-0.8, using an injection pressure of 10-20 MPa and nozzle diameters between 0.4 and 0.57 mm. These values seemed to be dependent on injection pressure since a lower value was obtained at an injection pressure of 20…”

Estudio De La Influencia De Las Características Del Flujo Interno en Toberas Sobre El Proceso De Inyección Diésel en Campo Próximo

“…Existen diferentes expresiones en la literatura que modelan el perfil radial de velocidad de un chorro diésel [47,105,112,119]. Desantes et al [29] hicieron un estudio comparativo de estos perfiles, llegando a la conclusión de que el que mostraba un mejor comportamiento a la hora de reproducir las características del chorro diésel es el perfil gaussiano propuesto anteriormente por Correas [22]:…”