Aluminum Adiabatic flame temperature

As mentioned in the previous section, the condition for vapor phase combustion versus heterogeneous combustion may be influenced by pressure by its effect on the flame temperature (Tvol or Td) as well as by its effect on the vaporization temperature of the metal reactant (Th). For aluminum combustion in pure oxygen, combustion for all practical conditions occurs in the vapor phase. In air, this transition would be expected to occur near 200 atm as shown in Fig. 9.15 where for pressures greater than —200 atm, the vaporization temperature of pure aluminum exceeds the adiabatic flame temperature. This condition is only indicative of that which will occur in real particle combustion systems as some reactant vaporization will occur at temperatures below the boiling point... 

FIGURE 9.15 Adiabatic flame temperatures and aluminum vaporization temperature as a function of pressure. 

The heat of combustion amounts to 7483 cal/g of aluminum fuel and the adiabatic flame temperature calculated by the NASA chemical equilibrium program [6] is 4005 K. The combustion equation for aluminum and steam is... 

The heat of combustion amounts to 4272 cal/g of aluminum fuel and the adiabatic flame temperature calculated by the chemical equilibrium program is 3036 K. Thus, the heat released when aluminum is burned with steam is about 57% of the amount released when aluminum is burned with O2. Many experimental investigations have been carried out on the combustion of aluminum in atmospheres where the primary oxidizer was O2 [7-16], and also in atmospheres where the primary oxidizer was H2O and/or CO2 [16-19]. There is general... 

Fig. 11.17 shows burning rate augmentation, Eb, as a function of the adiabatic flame temperatures of B-AP and Al-AP pyrolants. The incorporahon of aluminum particles into a base matrix composed of AP-CTPB pyrolant increases Ej. However, the effect of the addihon becomes saturated for adiabahc flame temperatures higher than about 2500 K. On the other hand, the incorporahon of boron particles into the same base matrix increases Eg more effectively, even though the adiabahc... 

AFT adiabatic flame temperature ALCOA Aluminum Company of America... 

Figure 5.2 Aluminum-oxygen combustion at (a) 1 and (b) lObar. Adiabatic flame temperature and main composition of combustion products.

In Figure 5.2, equilibrium computations for the adiabatic flame temperature of Al are reported for variable O/F ratios, along with the most important aluminum-based products. The highest temperature is obtained for O/F = 0.9, slightly shifted toward the fuel-rich side of the reaction 5.2. 

Figure 5.3 Aluminum-oxygen combustion. Prorducts and adiabatic flame temperature for varying pressure and constant O/F = 0.9.

Figure 5.4 Main reaction products at 10 bar (a) and adiabatic flame temperatures (b) of aluminum reaction with nitrogen.

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