LAMINAR HEAD-ON FLAME QUENCHING--A THEORETICAL STUDY (AUTOMOBILE ENGINE EMISSIONS)
Results of a numerical investigation of one-dimensional laminar flame quenching with constant and time-dependent pressure variations are reported. A description of flame quenching and postflame oxidation processes for a global reaction is obtained by solving a simplified form of nonlinear conservation of mass, momentum, and energy equations in a planar flow field. These equations are reduced to finite difference form, and time-dependent pressure is input via an integrated form of the energy equation or a third-order polynomial law. Numerical calculations were performed at constant-pressure, combustion bomb-type conditions and under rapid decompression during quenching. One-dimensional head-on quenching distances, hydrocarbon concentration levels, and gas properties were derived for various stoichiometric values in a propane/air-type mixture. Results indicate that quenching distance is primarily controlled by the thermal conduction process; however, residual hydrocarbon levels are intimately related to postquenching diffusion, oxidation kinetics, and the thermodynamic cycle during which they occur. Model calculations exhibit good agreement with experimental flame speed and demonstrate single-wall quench thicknesses which closely follow known experimental trends for the two-plate quench distance. Effects of transient pressure changes on postquench burn-up are examined, and results indicate that pressure variations on a time scale similar to that of the quenching process can account for a factor increase in predicted hydrocarbons, as compared with constant pressure calculations. Additional research is recommended to devise a multistep reduction reaction scheme that adequately describes the quenching process.
- Find a library where document is available. Order URL: http://worldcat.org/issn/01487191
- Presented at SAE International Fuels and Lubricants Meeting, Toronto, 13-16 November 1978.
Warrendale, PA United States 15096
- Adamczyk, A A
- Lavoie, G A
- Publication Date: 1978
- Features: References;
- Pagination: 23 p.
- TRT Terms: Combustion; Exhaust gases; Flames; Hydrocarbons; Temperature control (Structures); Vehicle power plants
- Old TRIS Terms: Automobile engines; Quenching /cooling/
- Subject Areas: Safety and Human Factors; Vehicles and Equipment;
- Accession Number: 00399226
- Record Type: Publication
- Source Agency: National Highway Traffic Safety Administration
- Report/Paper Numbers: SAE 780969, HS-025 912U
- Files: HSL, USDOT
- Created Date: Oct 31 1985 12:00AM