- Author
-
Tuovinen, H.
|
Simonson, M.
- Title
- Incorporation of Detailed Chemistry Into CFD Modelling of Compartment Fires.
- Coporate
- SP Swedish National Testing and Research Institute, Boras, Sweden
- Report
-
SP Report 1999:03
1999
38 p.
- Distribution
- For more information contact: SP Swedish National Testing and Research Institute, Box 857, SE-501 15 BORAS, Sweden. Telephone: +46 33 16 50 00, Fax: +46 33 13 55 02, Email: [email protected] Website: http://www.sp.se/eng/default.htm
- Keywords
-
compartment fires
|
computational fluid dynamics
|
reaction kinetics
|
soot formation
|
scalar dissipation
- Identifiers
- flamelet model; underventilated fires; gas layer
- Abstract
- Flamelet calculation for heptane, propane and methane with and without fire gas re-circulation have been made. The calculations are performed using so called Arclength Continuation Method, in which a system of differential equations is solved by including the inverse of the scalar dissipation rate as a variable. The calculations are based on 2000 elementary reaction steps involving more than 100 species. The flamelets for both cold (300 K) and hot (1000 K) combustion product re-circulation have been calculated. The strain is also included in the calculation; also the scalar dissipation rates from 0.01/s to extinction values have been varied. From this main data base the flamelet library for heptane has been made, which can be sourced directly by the CFD code SOFIE. Only the major species, O2, H2O, CO, CO2, N2 and fuel are taken into account in this first approach. Although, the effect of other intermediate species on the enthalpy has been added to the mixture enthalpy. The flamelet library has been used to simulate a fire in a rock tunnel with and without re-circulation of combustion gases. The simulated temperatures and major species concentrations agree well with measured results. The chemistry of hot gas layer has been investigated with respect to CO production with the chemical kinetics code CHEMKIN. The different parameters varied are the equivalence ratio, temperature, oxygen, unburned fuel, and incomplete combustion products. A simple calculation of soot formation in the gas layer has also been made. The results show that in the presence of acetylene in rich mixtures the soot production rateis proportional to acetylene concentration. The soot formation increases rapidly when the temperature is increased to about 900 dec C. An increase in the O2 concentration drastically decreases the soot formation.