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From page 40... ... Commercial Space Vehicle Emissions Modeling 29 4 Database of Emissions Indices The commercial space vehicle emissions model uses emissions indices to estimate the total amounts of the various pollutants emitted by space vehicles. As discussed in Section 3, emissions indices are the factors that relate the amount of propellant burned to the amount of each pollutant emitted by a rocket engine. Read the entire page →
From page 41... ... Commercial Space Vehicle Emissions Modeling 30 4.2 Primary Emissions Indices As discussed in Section 2.1, the primary emissions are the chemical species present at the nozzle exit plane due to processes that occur inside the rocket engine. If high-quality predictions or measurements of the primary emissions indices for a space vehicle are publicly available in the literature, the published values are used in the commercial space vehicle emissions model. Read the entire page →
From page 42... ... Commercial Space Vehicle Emissions Modeling 31 CEA implements sophisticated and well-validated models for calculating the chemical equilibrium of complex chemical systems. However, the theoretical rocket engine performance calculations are based on numerous simplifying assumptions [111] Read the entire page →
From page 43... ... Commercial Space Vehicle Emissions Modeling 32 Figure 20. Overview of the method for estimating the final emissions indices. Read the entire page →
From page 44... ... Commercial Space Vehicle Emissions Modeling 33 No molecular weight ratio is needed for the hydroxyl term in Eq. Read the entire page →
From page 45... ... Commercial Space Vehicle Emissions Modeling 34 Based on Eq. Read the entire page →
From page 46... ... Commercial Space Vehicle Emissions Modeling 35 Figure 22. Mass fractions of HCl, Cl, and Cl2 relative to the total mass of chlorine-containing molecules as functions of altitude [15, 18-20] Read the entire page →
From page 47... ... Commercial Space Vehicle Emissions Modeling 36 Figure 23 shows calculations of the NOx secondary emissions index from previous studies of the Space Shuttle [15, 18] as well as the Atlas V RD-180 and Delta IV RS-68A liquid rocket engines [23, 24] Read the entire page →
From page 48... ... Commercial Space Vehicle Emissions Modeling 37 4.3.6 Black Carbon Black carbon (BC) , also known as soot, is produced inside rocket engines by incomplete combustion of carbon-based propellants. Read the entire page →
From page 49... ... Commercial Space Vehicle Emissions Modeling 38 A reasonable estimate for the primary emissions index of black carbon is given by the final emissions index at high altitudes, where afterburning is negligible. The results shown in Figure 24 suggest that the primary emissions index of black carbon is 25 g/kg for LOX/RP-1 propellants. Read the entire page →
From page 50... ... Commercial Space Vehicle Emissions Modeling 39 The first-order estimate of the black carbon emissions index for LOX/RP-1 engines is already highly uncertain, and the estimates for the other propellants have an even greater amount of uncertainty. Future measurements will be required to reduce the uncertainty and provide more accurate black carbon emissions indices for different types of propellants. Read the entire page →
From page 51... ... Commercial Space Vehicle Emissions Modeling 40 Table 7. Estimates of the primary emissions indices, in grams of pollutant emitted per kilogram of propellant consumed, for first-stage rocket engines. Read the entire page →
From page 52... ... Commercial Space Vehicle Emissions Modeling 41 However, high-quality predictions or measurements of the emissions indices are not publicly available for the remaining launch vehicles. Thus, most of the primary emissions indices listed in Table 7 were estimated using CEA. Read the entire page →
From page 53... ... Commercial Space Vehicle Emissions Modeling 42 Table 8. Estimates of the final emissions indices, in grams of pollutant emitted per kilogram of propellant consumed, for first-stage rocket engines at sea level. Read the entire page →
From page 54... ... Commercial Space Vehicle Emissions Modeling 43 Figure 25. Estimates of the final emissions indices, in grams of pollutant emitted per kilogram of propellant consumed, for selected firststage rocket engines at sea level. Read the entire page →
From page 55... ... Commercial Space Vehicle Emissions Modeling 44 Final Emissions Indices at 40 km Table 9 lists the final emissions indices at an altitude of 40 km (25 mi) in the upper stratosphere for the same first-stage rocket engines. Read the entire page →

From page 40...

... Commercial Space Vehicle Emissions Modeling 29 4 Database of Emissions Indices The commercial space vehicle emissions model uses emissions indices to estimate the total amounts of the various pollutants emitted by space vehicles. As discussed in Section 3, emissions indices are the factors that relate the amount of propellant burned to the amount of each pollutant emitted by a rocket engine.