This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
Analysis of Evaporating Fuel Films Using Shadowgraph and Schlieren Imaging Techniques
Technical Paper
2008-01-2443
ISSN: 0148-7191, e-ISSN: 2688-3627
Annotation ability available
Sector:
Language:
English
Abstract
Fuel spray impingement and the formation of a fuel film in the intake port of port-injected engines or on the piston crown of direct-injected engines have been shown to result in increased pollutant emissions and reduced engine performance. While models that predict the nature of fuel film evaporation exist, little experimental data on the evaporation characteristics of fuel films have been published. This paper discusses the use of two closely related imaging techniques, shadowgraphy and schlieren photography, to measure the transient evaporation rate, surface area, and thickness of evaporating films, as well as the thickness and concentration distribution of the vapor layer that forms directly above the films. The measurements were conducted in order to better understand the interdependent transport phenomena that control the evaporation process. Although this work is motivated by the problems caused by fuel films in engines, the experiments were conducted outside of an engine under conditions that are easy to control. Two advantages of using imaging techniques to study film evaporation are that such methods are non-intrusive and they can have high temporal resolution through the use of a high-speed camera. The results of these imaging experiments indicate that under the conditions studied, the gravitational force has a strong influence on the evaporation rate through its effect on the vapor layer thickness.
The shadowgraph method was applied to obtain images of the profile of the film during the course of film evaporation. For each recorded image, the mass, surface area, and thickness of the film were computed. The evaporation rate and the transient changes in surface area and film thickness were computed from the images recorded over time at a rate of 60 images/second. To validate the mass and evaporation rate results of the shadowgraph experiments, simultaneous measurements of the film mass were made using an analytical balance.
The schlieren technique utilizes gradients in indices of refraction of transparent media (e.g. the vapor from an evaporating film) to construct images whereby these media may be observed visually. This technique was used to obtain qualitative and semi-quantitative information about the vapor layer that quickly forms above the evaporating film. The vapor layer thickness and the spatial distribution of the vapor concentration were estimated quantitatively for each schlieren image and their changes were computed from images recorded over time.
Because of the large number of images acquired per experiment, automation of the image analysis was essential. Computer programs were written using Matlab to identify the liquid and vapor boundaries and to compute the various characteristics of the evaporating film.
Recommended Content
Journal Article | Inner Diesel Injector Deposit Formation Mechanism |
Aerospace Standard | Oxygen Cylinder Quality, Serviceability, Maintenance Transfilling, and Marking |
Technical Paper | Calculation of Piston Ring Radial Pressure Distribution from its Measured Free Shape |
Authors
Citation
French, W., Rose, D., Kelly-Zion, P., and Pursell, C., "Analysis of Evaporating Fuel Films Using Shadowgraph and Schlieren Imaging Techniques," SAE Technical Paper 2008-01-2443, 2008, https://doi.org/10.4271/2008-01-2443.Also In
References
- Nogi, T. Ohyama, Y. Yamauchi, T. Kuroiwa, H. “Mixture Formation of Fuel Injection Systems in Gasoline Engines,” SAE Technical Paper No. 880558 New York, NY 1988
- Alkidas, A. C. “The Effects of Fuel Preparation on Hydrocarbon Emissions of a S.I. Engine Operating Under Steady-State Conditions,” SAE Technical Paper No. 941959 Detroit, MI 1994
- Witze, P.O. Green, R.M. “LIF and Flame Emission Imaging of Liquid Fuel Films and Pool Fires in an SI Engine during a Simulated Cold Start,” SAE Technical Paper No. 970866 Detroit, MI 1997
- Stevens, E. Steeper, R. “Piston Wetting in an Optical DISI Engine: Fuel Films, Pool Fires, and Soot Generation,” SAE Technical Paper No. 2001-01-1203 Detroit, MI 2001
- O'Rourke, P. Amsden, A. “A Particle Numerical Model for Wall Film dynamics in Port-Injected Engines,” SAE Technical Paper Series No. 961961 San Antonio, TX 1996
- Stanton, D. Rutland, C. “Multi-Dimensional Modeling of Heat and Mass Transfer of Fuel Films Resulting from Impinging Sprays,” SAE Technical Paper Series No. 980132 Detroit, MI 1998
- Foucart, H. Habchi, C. Le Coz, J. Baritaud, T. “Development of a Three Dimensional Model of Wall Fuel Liquid Film for Internal Combustion Engines,” SAE Technical Paper Series No. 980133 Detroit, MI 1998
- Oliveira, I. Hockgreb, S. “Detailed Calculation of Heating, evaporation, and Reaction Processes of a Thin Liquid Layer of Hydrocarbon Fuel,” SAE Technical Paper Series No. 2000-01-0959 Detroit, MI 2000
- Kelly-Zion, Peter Collins, William Glawe, Diana “Application of Laser Interferometry for Transient Film Thickness Measurements,” ASME Technical Paper No. HT-FED2004-56693 Proceedings of the ASME Heat Transfer/Fluids Engineering Summer Conference Charlotte, NC 2004
- Yang, Jiemin Melton, Lynn A. “Fluorescence Based Method Designed for Quantitative Measurement of Fuel Film Thickness during Cold-Start of Engines,” Applied Spectroscopy 54 565 574 Society for Applied Spectroscopy Lawrence, KS 2000
- Pak, Hyuk K. Law, Bruce M. “2D Imaging Ellipsometric Microscope,” Review of Scientific Instruments 66 4972 4976 American Institute of Physics College Park, Maryland 1995
- Shama, Gilbert Peppiatt, Christopher Biguzzi, Marina “A Novel Thin Film Photoreactor,” Journal of Chemical Technology and Biotechnology 65 56 64 John Wiley & Sons Ltd Chichester, England 1996
- Yildirim Erbil, H. McHale, G. Newton, M.I. “Analysis of Evaporating Thick Liquid Films on Solids,” Journal of Adhesion Science and Technology 16 1869 1881 VSP BV Zeist, The Netherlands 2002
- Shiozaki, T. Suzuki, T. Shimoda, M. “Observation of Combustion Process in D.I. Diesel Engine via High Speed Direct and Schlieren Photography,” SAE Technical Paper Series No. 800025 Detroit, MI 1980
- Weast, R. C. Astle, M. J. CRC Handbook of Chemistry and Physics 60th CRC Press, Inc. Boca Raton, FL C-81 C-731 1980
- Yaws, C. L. Thermodynamic and Physical Property Data Gulf Publishing Co. Houston, Chap. 5 1992
- Settles, G.S. Schlieren and Shadowgraph Techniques Springer-Verlag Berlin, Germany 2006