Prediction of the Impact of Nozzle Geometry on Spray Characteristics

Abstract

In the present paper, the formation and development of cavitation inside the nozzle of an atomizer with different geometrical characteristics have been studied numerically. Different shapes of inlet nozzles and different nozzle-length-to-diameter ratios have been investigated. The developed model has been built as a three-dimensional (3D) one, where the turbulence is modeled considering large eddy simulation. The obtained computational results showed good agreement with the reported experimental results. It has been found that the occurrence of cavitation depends on the amount of energy needed to overcome the viscosity and friction between the liquid layers. The mass flowing through the nozzle decreases with increasing cavitation. The intensity of cavitation depends on the nozzle entrance shape. Sharp edges cause cavitation to occur early in the nozzle, followed by an inclined shape, and then the curved entrance. The dissipative energy in the cavitation and bubble collapse result in an increase in the turbulent kinetic energy of the issuing liquid. This causes more liquid disintegration, leading to larger spray volume and smaller droplet size. The obtained results for spray droplet size distribution have been compared with experimental data developed by other researchers, and a good agreement has also been found.

Numerical Simulation and Experimental Study for the Impact of In-Flow Nozzle on Spray Characteristics

“…The mathematical model used for predicting the flow inside and outside of the nozzle hole is according to the previously developed work by the authors, 2 as illustrated in S1 ( Appendix-A ). It predicts the influence of the inflow on the outflow from the nozzle hole.…”

“…Understanding, and consequently be able to model the atomization process, is an important step to fine control the atomization mechanism such that the requested atomization characteristics can be achieved. 2 One of the most widely used atomization techniques is the mechanical atomization, in which the liquid is pressurized against a fine nozzle. 3 Understanding this basic atomization process will help in further understanding the spray formation process.…”

“…This depends on both the atomized liquid properties and the atomization system design. Understanding, and consequently be able to model the atomization process, is an important step to fine control the atomization mechanism such that the requested atomization characteristics can be achieved . One of the most widely used atomization techniques is the mechanical atomization, in which the liquid is pressurized against a fine nozzle .…”

Optimization on the jet characteristics of the main nozzle of hot-blowing snow removal device

“…According to the results, under the same flow conditions, the aspect ratio has a significant effect on the jet length and trajectory. Under the same nozzle spray area, a vertically oriented rectangular nozzle (that is, a nozzle with an aspect ratio of less than 1) has a deeper penetration than a horizontally oriented rectangular nozzle (that is, a nozzle with an aspect ratio of greater than 1) Mohamed et al [13] used numerical methods to study the formation and development mechanism of cavitation inside the nozzle by changing the shape of the nozzle. The results show that the strength of cavitation is directly related to the shape of the nozzle.…”