This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
Gasification of Porous Combustion Chamber Deposits in a Spark Ignition Engine
Annotation ability available
Sector:
Language:
English
Abstract
A computational investigation of the effects of activation energy, porosity, and pore size on the gasification of combustion chamber deposits in spark ignition engines has been performed. The oxygen in the combustion gases reacts with the carbonaceous deposit and causes the deposit to burn away. Experimentally measured deposit parameters such as heating value, surface temperature, surface pressure and porosity were used in the model.
Several models for predicting the gasification of the deposit were investigated. A random pore intersection model developed by Petersen was used to predict the gasification of the deposit. The chemical reactions were modeled with a simple Arrhenius expression. The flow within the deposit was modeled using Darcy's Law. The Kozeny-Carmen equation was used to relate deposit permeability and porosity. The model was incorporated into a finite difference code that predicts the heat transfer and fluid flow through the deposit.
Computed deposit gasification rates were compared to observations in a laboratory engine. The deposits formed in the engine were made up of three distinct layers in which the middle layer of the deposit appeared to gasify at a faster rate than the surface. Uniform activation energy always resulted in the deposit burning in a surface recession. Porosity distribution and specific surface area effects were not strong enough to account for middle layer gasification. A non-uniform activation energy was the only variable in the computational model which resulted in faster gasification rates in the middle layer.
Recommended Content
Authors
Citation
Wood, B. and Anderson, C., "Gasification of Porous Combustion Chamber Deposits in a Spark Ignition Engine," SAE Technical Paper 930773, 1993, https://doi.org/10.4271/930773.Also In
References
- Bethel, S. Anderson, C.L. “An In Situ Infrared Technique for Measuring Cycle-Resolved Transient Combustion-Chamber Surface Temperatures in a Fired Engine,” SAE Paper No. 860240
- Harder, R.F Anderson, C.L. “Investigation of Combustion-Chamber Deposit Thermal Behavior Utilizing Optical Radiation Measurements in a Fired Engine,” Combustion and Science 60 4-6 423 440
- Baker, T. “Catalytic Gasification of Graphite,” Chemistry and Industry London 18 1983
- Laurendeau, N.M. “Heterogeneous Kinetics of Coal Char Gasification and Combustion” Energy Combustion Science 4 Pergamon Press Ltd. 1978
- Kanury, A.M. Introduction to Combustion Phenomena Gordon and Breach Science Publishers New York 1975
- Heywood, J.B. Internal Combustion Engines McGraw Hill 1988
- Bear, J. Dynamics of Fluids in Porous Media American Elsevier New York 1972
- Anderson, C.L. Prakash, C. “The Effects of Variable Conductivity on Unsteady Heat Transfer Deposits,” SAE Paper No. 850048
- Xieu, D.V. et. al. “A Mathematical Model of a One-Dimensional Char Flame: A Comparison of Theory and Experiment,” Eighteenth Symposium (International) on Combustion 1981
- Petersen, E.E. “Reaction of Porous Solids,” AlChE Journal 3 1957
- Patankar, S.V. Numerical Heat Transfer and Fluid Flow McGraw Hill New York 1980