About: Spray characteristics is a research topic. Over the lifetime, 3352 publications have been published within this topic receiving 44666 citations.
Papers published on a yearly basis
TL;DR: In this article, the authors evaluated the effect of aerodynamic effects, liquid turbulence, jet velocity profile rearrangement effects, and liquid supply pressure oscillations on the atomization of a round liquid jet.
Abstract: In the atomization regime of a round liquid jet, a diverging spray is observed immediately at the nozzle exit. The mechanism that controls atomization has not yet been determined even though several have been proposed. Experiments are reported with constant liquid pressures from 500 psia (33 atm) to 2500 psia (166 atm) with five different mixtures of water and glycerol into nitrogen, helium, and xenon with gas pressures up to 600 psia (40 atm) at room temperature. Fourteen nozzles were used with length‐to‐diameter ratios ranging from 85 to 0.5 with sharp and rounded inlets, each with an exit diameter of about 340 μm. An evaluation of proposed jet atomization theories shows that aerodynamic effects, liquid turbulence, jet velocity profile rearrangement effects, and liquid supply pressure oscillations each cannot alone explain the experimental results. However, a mechanism that combines liquid–gas aerodynamic interaction with nozzle geometry effects would be compatible with our measurements but the specific process by which the nozzle geometry influences atomization remains to be identified.
TL;DR: In this paper, the interference fringe pattern produced by spheres passing through the intersection of two laser beams was used for measuring the size and velocity of spherical particles. But the results of the experiments were limited to the case of monodisperse droplet streams.
Abstract: Research was conducted on a laser light scatter detection method for measuring the size and velocity of spherical particles. The method is based upon the measurement of the interference fringe pattern produced by spheres passing through the intersection of two laser beams. A theoretical analysis of the method was carried out using the geometrical optics theory. The instrument response function was determined to be linear with drop size. Experimental verification of the theory was obtained by using monodisperse droplet streams. Several optical configurations were tested to identify all of the parametric effects upon the size measurements. Both off-axis forward-scatter and back-scatter light detection were utilized. Simulated spray environments and fuel spray nozzles were used in the evaluation of the method. The measurements of the monodisperse drops showed complete agreement with the theoretical predictions. The method was demonstrated to be independent of the beam intensity and extinction resulting from the surrounding drops. An instrument based on the concept has been developed.
TL;DR: In this paper, a study was carried out on the influence of cavitation on the internal flow and the macroscopic behavior of the spray in Diesel injection nozzles, and the results of this hydraulic characterisation, together with the predetermined dimensional characterization, enable the discharge coefficient and the critical cavitation conditions to be determined.
Abstract: A study was carried out on the influence of cavitation on the internal flow and the macroscopic behaviour of the spray in Diesel injection nozzles. For this study, two bi-orifice nozzles were used, one cylindrical, and the other convergent (conical). From the point of view of cavitation, the two chosen nozzles are very different, as the first nozzle is much more inclined to cavitate, whereas the second nozzle inhibits the cavitation phenomenon. First, in order to find the exact internal geometry of the two nozzles, a non-destructive characterisation method is used, which is based on the creation of silicone moulds. Once the nozzles are characterised dimensionally, a hydraulic characterisation is made. The results of this hydraulic characterisation, together with the predetermined dimensional characterisation, enable the discharge coefficient and the critical cavitation conditions to be determined. By identifying the critical cavitation conditions, it is possible to complete a study of the macroscopic parameters of the spray, with cavitating and non-cavitating conditions, and therefore a study can be carried out examining the influence of cavitation on the macroscopic spray behaviour. From the point of view of the spray macroscopic behaviour, the main conclusion of the paper is that cavitation leads to an increment of the spray cone angle. On the other hand, from the point of view of the internal flow, the hole outlet velocity increases when cavitation appears. This phenomenon can be explained by the reduction in the cross section of the liquid phase in the outlet section of the hole.
TL;DR: In this paper, the effect of cavitation on Diesel spray behavior was investigated in two bi-orifices nozzle geometries, a cylindrical nozzle and a convergent one, by means of two fundamental spray parameters: mass flux and momentum flux.
Abstract: Nowadays Diesel nozzle geometry is a major issue in order to fulfil new emission regulations due to the influence on internal flow, cavitation phenomenon, spray characteristics and therefore atomization behavior, which are very important for engines performance and pollutant formation. The aim of this article is to study the effect of cavitation on Diesel spray behavior. For this purpose, two bi-orifices nozzle geometries, a cylindrical nozzle and a convergent one, are characterized by means of two fundamental spray parameters: mass flux and momentum flux. Five injection pressure values and five discharge pressure levels have been measured in order to change the cavitation regime inside the nozzle flow. It is known from the literature that cavitation brings about a mass flux choke, but there are few studies that investigate its effects on momentum and outlet velocity in real geometries. The key point of this study is the measurement of spray momentum in order to explain the effects of nozzle geometry on spray behavior.
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