On the Modeling of Liquid Sprays Impinging on Surfaces

Mundo, Christian; Sommerfeld, Martin; Tropea, Cameron

doi:10.1615/atomizspr.v8.i6.20

Cited by 122 publications

(75 citation statements)

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“…Similar results have been also reported by Mundo et al (1998) and show that the liquid film starts to form in the vicinity of the stagnation region at early stages of injection. At outer regions (r > 4 mm) a non-negligible part of droplets impinging during LFS and SS periods is ejected after having interacted with the wall by mechanisms of rebound and splash, as described in Panão and Moreira (2004).…”

Section: Fig 8 -Time Variation Of the Energy Transfer Coefficient (αsupporting

confidence: 91%

“…In general, Figure 4b) shows that the impact increases the transverse momentum of droplets. This feature is either due to transfer of the normal momentum of inflowing droplets into the transverse component, as reported by Mundo et al (1998), or to interaction with the time growing liquid film which rapidly spreads onto the surface, as suggested in Panão and Moreira, 2004.…”

Section: Effects Of the Target Surface On Spray Structurementioning

confidence: 80%

“…5 is close to unity (α M = 1), while under-predicted values correspond to those for which 0 < α M < 1. This observation clearly suggests that discrepancies between experiments and predictions may be attributed to the interaction of the polydispersed spray with the impacted transient liquid film: the model is not able to account for the deposited mass in the region where α M = 1, neither is not able to account for the possible increase of the size of secondary droplets when the spray impacts onto a liquid film where 0 < α M < 1 (e.g., Mundo et al 1998). An attempt is made here to account for the effect of the liquid film based on the transfer coefficients analysed in Fig.…”

Section: Influence Of Mass Momentum and Energy Fractions Transferredmentioning

confidence: 99%

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Flow characteristics of spray impingement in PFI injection systems

Panão¹,

Moreira²

2005

Exp Fluids

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Internal Combustion engines with multi-point, or sequential, fuel injection have a fuel injector for each cylinder, usually located so that they spray right at the intake valve. While in a fully warmed-up engine, fuel droplets vaporize before entering the combustion chamber, at cold start, a significant proportion of the injected gasoline deposits on the intake port and valve surfaces. The result is a deterioration of mixture homogeneity, decreased metering accuracy and increased hydrocarbon emissions. A better control of mixture preparation at cold start conditions can be achieved if the interaction between the gasoline spray and the time-varying liquid film which forms during the period of injection can be accurately predicted. The work reported here considers part of an experimental study performed with that objective in a purposed built experiment considering a simplified geometry.Droplet characteristics measured with a PDA system in the vicinity of the impact surface, prior and right after the impact, are used to infer about the transient spray-wall interaction mechanisms when a liquid film forms. Conservation laws allow to derive the fractions (α θ ) of mass, momentum and energy from the spray prior to impact that are transferred to/from the liquid film. Most of the inflowing mass deposits within the core of the spray and transfers momentum to the liquid film in the radial direction, influencing the velocity and direction of secondary droplets formed at impingement. The use of α θ , together with the mass flux ratio of outgoing to inflowing droplets in existing empirical correlations to predict the impingement outcome, is shown to improve prediction of flux ratios, either of number, momentum or energy. These fractions are suggested as a simple way of including the influence of the liquid film in spray/wall interaction and their modelling is the scope of future work. LFS SS ST LFS SS ST

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Section: Fig 8 -Time Variation Of the Energy Transfer Coefficient (αsupporting

confidence: 91%

Section: Effects Of the Target Surface On Spray Structurementioning

confidence: 80%

Section: Influence Of Mass Momentum and Energy Fractions Transferredmentioning

confidence: 99%

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Flow characteristics of spray impingement in PFI injection systems

Panão¹,

Moreira²

2005

Exp Fluids

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“…The values of the present simulation (2630, 1680) are close to this range. Figure 3 of Mundo et al (1998) shows a similar jet appearing in their numerical simulation of a drop impacting a liquid layer, but they do not report values of Re or We. In the present simulation, there were 429 510 cells in the grid when this jet was observed.…”

Section: Drop Hitting a Wallmentioning

confidence: 97%

Electromagnetic Control of High Heat-Flux Spray Impingement Boiling Under Microgravity Conditions

Gray¹,

Kuhlman²,

Glaspell³

et al. 2007

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Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources. gathering and maintaining the data needed, and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this cOllectioni of information, including suggestions for reducing this burden to Departnient of Defense. Washington Headquarters Services, Directorate for Information Operations and . 1215 Jefferson Davis Highway, Suite 1204, Arlington. VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information i it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. REPORT DATE (DD-MM-YYYY)2. REPORT TYPE 14. ABSTRACT The primary goal of this project was to discover how to most effectively use electromagnetic forces to enhance spray impingement boiling heat transfer in microgravity (jg). This project was closely coordinated with the non-electromagnetic spray impingement boiling experiments conducted by Dr. Kirk L. Yerkes of the Air Force Research Laboratory (AFRL) . The West Virginia University (WVU) investigation of electrical body forces to enhance and control spray impingement boiling extended the AFRL research. The computational phase of the WVU project was based on the commercial multiphysics code CFD-ACE+, which was successfully modified to incorporate the Coulomb and electric Kelvin forces. DATES COVERED (From -ToWVU's ground-based experiments demonstrated for the first time that modest increases in heat transfer coefficient and Nusselt number can be achieved in spray impingement boiling by using electrical forces, thus confirming the fundamental hypothesis of this research.Further increases in heat transfer performance are likely to result from a better understanding of the relevant microphysics and better electrode designs. Experimental results have been used to estimate the time scales for various phenomena that occur in spray impingement boiling, which could lead to improved electrode designs. SUBJECT ABSTRACTThe primary goal of this project was to discover how to most effectively use electromagnetic forces to enhance spray impingement boiling in microgravity (ýLg). This project was closely coordinated with the non-electromagnetic spray impingement boiling heat transfer experiments conducted by Dr. Kirk L. Yerkes of the Air Force Research Laboratory (AFRL). The West Virginia University (WVU) investigation of electrical body forces to enhance and control spray impingement boiling extended the AFRL research. The computational phase of the WVU project was based on the commercial multiphysics code CFD-ACE+, which was successfully modified to incorporate the Coulomb and electric Kelvin forces. WVU's ground-based experiments demonstrated for the first time that modest increases in heat tra...

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“…The tendency for oil splashing depends on the properties of the water droplets, such as droplet size and velocity, as well as the properties of oil and its depth [26][27][28][29][30]. Table 3 shows the physical properties of water, gasoline, diesel fuel and some cooking oils [6,31,32].…”

Section: Water Mist Splash Testsmentioning

confidence: 99%

Extinguishment of Cooking Oil Fires by Water Mist Fire Suppression Systems

et al. 2004

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/npsi/ctrl?lang=en http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/ctrl?lang=fr Access and use of this website and the material on it are subject to the Terms and Conditions set forth at http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/jsp/nparc_cp.jsp?lang=en NRC Publications Archive Archives des publications du CNRCThis publication could be one of several versions: author's original, accepted manuscript or the publisher's version. / La version de cette publication peut être l'une des suivantes : la version prépublication de l'auteur, la version acceptée du manuscrit ou la version de l'éditeur. For the publisher's version, please access the DOI link below./ Pour consulter la version de l'éditeur, utilisez le lien DOI ci-dessous.http://dx.doi.org/10.1023/B:FIRE. 0000039161.18616.86 Fire Technology, 40, 4, pp. 309-333, 2004-10-01 ABSTRACTA series of full-scale experiments were conducted in a mock-up commercial cooking area to study extinguishing mechanisms and effectiveness of water mist against cooking oil fires. The impact of water mist characteristics, such as spray angle, droplet size, flow rate, discharge pressure and type of nozzle, on the effectiveness of water mist against cooking oil fires was investigated. A series of oil splash experiments were also conducted to determine if the oil was splashed by water mist. In addition, the change in oil composition during heating and fire suppression was determined using Fourier Transform Infrared (FTIR) technique.The study showed that cooking oil fires were very difficult to extinguish, because they burned at high temperature and re-ignited easily due to changes in oil composition during heating and fire suppression. The water mist systems developed in the present work effectively extinguished cooking oil fires and prevented them from re-ignition. The spray angle, discharge pressure, and water flow rate were important factors to determine the effectiveness of water mist in extinguishing cooking oil fires.

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On the Modeling of Liquid Sprays Impinging on Surfaces

Cited by 122 publications

References 0 publications

Flow characteristics of spray impingement in PFI injection systems

Flow characteristics of spray impingement in PFI injection systems

Electromagnetic Control of High Heat-Flux Spray Impingement Boiling Under Microgravity Conditions

Extinguishment of Cooking Oil Fires by Water Mist Fire Suppression Systems

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