| OCR Text |
Show representative synthetic fuel, SRC-II MD, as described in detail in Ref. 10. The choice of chemical species to represent No. 2 fuel oil for the purpose of the development of a quasiglobal chemical kinetics mechanism was based on _the criteria that the neat hydrocarbons selected be constituents of No. 2 fuel oil -and have properties which closely match those of the more complex fuel. These criteria led to the selection of a 65% by volume dimethyl tetral in, 35% pentadecane mixture to represent the fuel. The close agreement of the properties of this mixture with those of No. 2 fuel oil is indicated by the data presented in Table 3. An SRC-II MD fuel model was also developed, based on species composition data reported in Ref. 5. These data indicated that all of the paraffinic compounds of SRC-II MD are present as side chains in aromatics and cyclic alkanes. Furthermore, to match the mean molecular weight with a limited number of species, fuel-bound nitrogen must be present in molecules larger than pyridine. The best match of observed species types and predicted properties was found to be a mixture of 41% (by volume) methyl ethyl phenol, 48.5% methylethylnaphthalene, and 10.5% decahydroquinolene. A comparison of SRC-II MD properties with those computed for this idealized structure is given in Table 4. Simulation Of SRC-II MD And No. 2 Fuel Oil Combustion With Quasiglobal Kinetics Model As outlined in the preceding section, SRC-II MD can be characterized by a mixture of two aromatic compounds (methylethylphenol and methylethylnaphthalene) and one heterocyclic compound (decahydroquinoline). Similarly, No. 2 fuel oil can be described by a mixture of one aromatic compound (dimethyltetralin) and one aliphatic compound (pentadecane). To adapt the quasiglobal kinetics model to these fuels, ethylene is considered to be the secondary fuel for aliphatic fuel component combustion, and acetylene is considered as the secondary fuel for aromatic fuel combustion. Based on these model fuel definitions, the subglobal and soot formation steps of the toluene/isooctane quasiglobal model are rewritten as shown in Table 5; the elementary steps comprising the thermal and fuel-bound NO mechanisms, the HC fragmentation mechanism, and the HCHO, H-O-, and wet CO mechanisms all are as shown in Table 2. Thus the subglobal steps in Table 5 and the elementary mechanisms given in Table 2 comprise the quasiglobal kinetics formulation for SRC-II MD and No. 2 fuel oil. Methylethylphenol and methylethylnaphthalene, two of the fuel components selected to model SRC-II MD, and dimethyltetralin, a fuel component used to model No. 2 fuel oil, are described by the aromatic kinetics mode. Pentadecane, used in the No. 2 fuel oil model, is modeled using the aliphatic kinetics model. Decahydroquinoline, the source of fuel-bound nitrogen in the model representation 1.2.23 |
