Showing 4 results for Atomization
Soudeh Khosravi, Mohamadreza Ansari,
Volume 12, Issue 2 (6-2012)
Abstract
Abstract: in this article, jet flow from the nozzle exit was considered and calculated numerically in transient two-phase flow and two-dimensional axsymmetric turbulent condition using volume of fluid method (VOF). The hydrodynamical instability for jet flow was analyzed and the breakup length was calculated, the nozzle diameter of 0.11875mm, 0.2375mm and 0.475 mm, the center line velocity of the fluid in the 15.416 m/s and 7.708 m/s and the fluid inside the nozzle used for the calculation are water and gas oil. Fluent 6.3.26 was used for two-phase flow analysis. The results obtained from the present numerical simulation compared with the experimental results of the previous researches, good agreement was obtained. It was concluded that the breakup length decreases as the relative velocity between the phases increase or the liquid density decreases. The nozzle diameter is an important parameter which effect of the nozzle outlet regime and the breakup length.
Seyed Mostafa Hosseinalipour, Hadiseh Karimaei, Fathollah Ommi,
Volume 14, Issue 10 (1-2015)
Abstract
In this paper, 5 samples of one kind of swirl injector with tangential inlets, which has been designed and manufactured by using CNC, have been tested. Above injector has a spray cone in the shape of very thin layer because it is formed an air core in injector center. In fact, this is a one-fluid injector but its operation is two-phase. In order to detect acceptable injector among them, characterization tests have been done in the propulsion laboratory of Tarbiat Modarres University for all sample injectors. The methods of experimental characterization have been described in detail in current paper and also important parameters introduced. In these tests, injection uniformity, symmetry, mass flow rate versus pressure difference and some other parameter such as spray cone angle are investigated. Experimental results have been compared with design points. Finally, one injector has been selected as a suitable and nearer to theoretical design injector among them. The selected injector can be used for validation of numerical analysis results and also doing some complemental microscopic experiments. The results show good agreement between theoretical predictions and experimental results.
Volume 17, Issue 3 (5-2015)
Abstract
The aim of the present study was to investigate the influence of nozzle configurations on spray drift and explain the influences using several atomization characteristics (length of spray sheet, spray angle, velocity distribution of flow field, fluctuation of velocity, and droplet size). Nozzles manufactured by one company (Lechler GmbH, Germany) were tested by spraying local tap water in a wind tunnel at an operating pressure of 0.3 MPa and under room temperature. The nozzles tested were compact air-induction flat fan nozzles (IDK120-02, IDK120-03), standard flat fan nozzles (ST110-02, ST110-03), and hollow-cone swirl nozzles (TR80-02, TR80-03). The atomization process was recorded using a Particle Image Velocimetry (PIV) system, droplet size was measured by a Sympatec Helos laser-diffraction particle-size analyzer, and spray drift was evaluated in a wind tunnel with deposition measured using a calibrated fluorometer (Turner-Sequoia model 450). Results showed that spray drift was significantly different among nozzle types (P<0.0005) and that nozzle configurations influenced breakup length, spray angle, droplet size, and velocity. Nozzles producing larger droplet sizes had lower velocity. Smaller droplets were produced when longer and wider spray sheets were produced. Compared to ST and TR nozzles, IDK nozzles started to breakup in the center of the liquid sheet, producing droplets with larger diameter, lower velocity, and less velocity fluctuation. The IDK nozzle is a good choice for low spray drift at higher wind speeds.
Gh. Olyaei, A. Kebriaee ,
Volume 19, Issue 4 (4-2019)
Abstract
The present study was performed to experimentally investigate the regime of the liquid sheet breakup and the effects of dimensionless numbers on the penetration and trajectory of the liquid sheet in cross flow condition. The shadowgraphy technique was applied to study the tests. In this work, the effect of the non-dimensional numbers (momentum ratio and Weber number) were surveyed on the breakup of the liquid sheet. Also, some equations for the injection trajectory, the length, and the height of the jet were presented based on these non-dimensional numbers. The tests were done at atmospheric pressure and temperature, where the Weber number range is from 0.8 to 12.5, the variations of the momentum ratio are from 17.4 to 250, and the changes in the Reynolds number are from 2400 to 10227. Three regimes of jet breakup were observed, defined as column breakup, column-bag breakup, and bag breakup. The Weber number is the most effective parameter in the regime change of the liquid sheet breakup. The results also indicated that the increase in the momentum ratio has a great influence on the depth of penetration of the liquid sheet, but it has a very small effect on the breakup regimes.
