Vaporization of Individual Fuel Drops on a Heated Surface: A Study of Fuel-Wall Interactions within Direct-Injected Gasoline (DIG) Engines

Stanglmaier, Rudolf H.; Roberts, Charles E.; Moses, C. A.

doi:10.4271/2002-01-0838

Cited by 30 publications

(11 citation statements)

References 20 publications

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“…(see [5] for a complementary bibliographical review. These critical temperatures may also be determined experimentally from the boiling or lifetime curve of a droplet as depicted in Figure 4 obtained by measuring the total time that it takes to a droplet to completely evaporate after it has been gently deposited on a hot wall [12] : Regime I, complete wetting regime (Tw < Tsat) The sprays, impinging a wall having a Tw smaller than Tsat, always form a liquid film which evaporates slowly. In this regime, the evaporation rate strongly depends on the turbulence level in the ambient gas [3,4,13,14].…”

Section: Methodsmentioning

confidence: 99%

“…The validation is carried out using two different experiments. First, the experimental lifetime curve of a sessile droplet from [12] is used for a quantitative validation in the different boiling regimes at resolved and SGS numerical conditions. Second, the wall impingement of a heptane spray from a prototype GDI injector from Continental Automotive, has been simulated.…”

Section: Models Validationmentioning

confidence: 99%

“…In the experiments of Stanglmaier et al [12], a rather big droplet (ܸ ൌ 5μ݈ሻ is deposited on an aluminium heated plate. Once deposited gently on the wall, this droplet spreads and forms a liquid film.…”

Section: Sessile Drop Test Cases : Numerical Validationsmentioning

confidence: 99%

See 2 more Smart Citations

Experimental and Numerical Investigation of Dispersed and Continuous Liquid Film under Boiling conditions

Habchi¹,

Lamarque²,

Hélie³

et al. 2017

Proceedings ILASS–Europe 2017. 28th Conference on Liquid Atomization and Spray Systems

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In this work, both experimental and numerical investigations have been carried out in order to improve the modelling of the vaporization of wall liquid-deposits in internal combustion engines. A comprehensive model is suggested for the vaporization of liquid films in the different boiling regimes, including nucleate boiling regime, the Leidenfrost boiling regime, as well as the transition boiling regime occurring between the two latter. This work extends the validity of the Liquid Film Boiling model (Habchi, Oil & Gas Science and Technology -Rev. IFP, Vol. 65, No. 2, 2010) for dispersed liquid films that may be formed when a dilute spray impinges a wall. A sub-grid liquid film is indeed considered when the wetted-area is smaller than the wall cell-face area. A sessile droplet model is used to estimate the wall area wetted by the liquid film and whether it is resolved by the grid or located in the sub-grid scale (SGS). In addition, a novel Leidenfrost vaporization model is proposed for spray droplets located near a hot wall. The above vaporisation/boiling models has been implemented in the Large-Eddy simulation (LES) AVBP code. The validation has been carried out using two different experiments. First, the experimental lifetime curve of a sessile droplet (Stanglmaier et al., SAE paper 2002-01-0838) has been used for a quantitative validation in the different boiling regimes. Second, the wall impingement of a heptane spray from a typical gasoline injector from Continental Automotive, has been simulated. The numerical results obtained under boiling conditions, are compared to the liquid film footprints and lifetime provided by the Refractive Index Matching (RIM) experiment which is described in this article. Keywords Liquid film, Boiling, Leidenfrost, LES, RIM IntroductionIn Gasoline Direct Injection (GDI) engines, the impingement of the spray on the walls cannot be avoided in all operating conditions. Therefore, a fine tuning of the operating points involving impact of the spray droplets on the inner walls of the engine must be performed. Computational Fluid Dynamics (CFD) codes are often used for this purpose. However, the modelling of all the spray-wall interactions, including evaporation and the different boiling regimes, remains challenging. In this work, both an experimental and a numerical investigation have been carried out in order to improve the understanding and the modelling of the vaporization of liquid deposits in the boiling regimes. The liquid film sub-models previously developed by the authors [1-5] using a RANS approach have been improved and implemented in the Large-Eddy Simulation (LES) code AVBP [6]. In particular, this work extends the validity of the Liquid Film Boiling (LFB) model [5] for dispersed liquid films or tiny deposits that may be formed when a dilute spray impinges a wall. In addition, experimental measurements have been carried out using the Refractive Index Matching (RIM) method described in Section 1. Next, the different physical sub-models and improvements suggested i...

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Section: Methodsmentioning

confidence: 99%

Section: Models Validationmentioning

confidence: 99%

See 1 more Smart Citation

Experimental and Numerical Investigation of Dispersed and Continuous Liquid Film under Boiling conditions

Habchi¹,

Lamarque²,

Hélie³

et al. 2017

Proceedings ILASS–Europe 2017. 28th Conference on Liquid Atomization and Spray Systems

View full text Add to dashboard Cite

show abstract

“…vaporization rates at a given wall temperature increase as ambient pressure increases. The lower temperature regime behavior is explained by an increased partial pressure of the vaporized fuel molecules above the film as ambient pressure increases (the wall film is so thin that it is essentially at the wall temperature); the higher temperature behavior is explained by a compression of the vapor layer that hinders heat transfer as ambient pressure increases [43].…”

Section: Effect Of Ambient Pressurementioning

confidence: 99%

Effect of In-Cylinder Liquid Fuel Films on Engine-Out Unburned Hydrocarbon Emissions for an SI Engine

Costanzo¹,

Heywood²

2012

SAE Technical Paper Series

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“…This slow depletion/vaporization of fuel film on the piston crown resulted in the insensitiveness of injection timing on the HC emissions in the test of Stanglmaier et al (1999). Later, Stanglmaier et al (2002) performed a fuel drop (φ=2 mm) evaporation test on a heated surface for different ambient pressures. The vapor insulation (Leidenfrost phenomenon) was strongly dependent on the boiling point of the fuel, and was proposed to explain the higher HC emissions for the fuel having the lower boiling point in the test of Huang et al (2001).…”

Section: -3-2 Piston Fuel Film Behavior and The Effect On Emissionsmentioning

confidence: 99%

Fuel Film Temperature and Thickness Measurements on the Piston Crown of a Direct-Injection Spark-Ignition Engine

Park¹,

Ghandhi²

2005

SAE Technical Paper Series

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The fuel film thickness and temperature on the piston crown of a direct-injection spark-ignition (DISI) engine were measured using a fiber-based laser induced fluorescence (LIF) method. The engine investigated employed a wall-guided swirl-type system using a high-pressure swirl injector impinging onto the piston crown. The fuel used was isooctane with a small amount of a fluorescent liquid dopant. The measured fluorescence intensity was transformed to the fuel film thickness by way of the equations based on photophysics and the fiber optic properties. However, the fluorescence of the fuel mixture showed a strong dependency on the fuel temperature and this information was needed in the fuel film thickness calculation. The fuel film temperature, which may differ from the piston surface temperature, was measured by using a fiber-based fluorescence thermometry method.Engine tests were performed for motored and fired conditions under the late injection stratified mode. The results of the fuel film temperature measurement showed that the mean fuel film temperature follows the piston surface temperature and the convection heat transfer from the compressed hot air directly affected the mean fuel film temperature during the compression and expansion stroke. The fuel film thickness measurement results showed that the boiling point of the liquid dopant should be much higher than that of the main fuel to ii meet the co-evaporation condition. The fuel film persisted during the expansion stroke and started to evaporate actively from the exhaust valve opening crank angle for both motored and fired conditions. The fuel film thickness from the fuel injection to just before the occurrence of pool fires was the same level for motored and fired engine conditions although the piston temperature was higher for the fired condition. The spark ignition and the main flame before the pool fires do not affect the fuel film thickness. The duration and thickness of the fuel film was strongly affected by the boiling point of the fuel. The fuel film evaporates quicker for a fuel having a lower boiling point.

show abstract

Vaporization of Individual Fuel Drops on a Heated Surface: A Study of Fuel-Wall Interactions within Direct-Injected Gasoline (DIG) Engines

Cited by 30 publications

References 20 publications

Experimental and Numerical Investigation of Dispersed and Continuous Liquid Film under Boiling conditions

Experimental and Numerical Investigation of Dispersed and Continuous Liquid Film under Boiling conditions

Effect of In-Cylinder Liquid Fuel Films on Engine-Out Unburned Hydrocarbon Emissions for an SI Engine

Fuel Film Temperature and Thickness Measurements on the Piston Crown of a Direct-Injection Spark-Ignition Engine

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