Luminosity pressure

Allowance for spectral overlap, the effect of pressure, and the effect of soot luminosity would make computation tedious. Table 5-8 gives constants for use in direct calculation, for H9O/CO9 mixtures, of the product cT The product term is used because it varies much less with T than does c alone. Constants are given for mixtures, in nonradiat-ing gases, of water vapor alone, CO9 alone, and four p Jpc mixtures. 

When pressure-decay rates less than critical are employed, the gas-phase combustion zone is removed from the propellant surface and extinguished, but not the ignition from within the condensed phase. Therefore, the temperature of the surface material will be above the autoignition temperature, and steady-state combustion will eventually be initiated. This mechanism is consistent with the observation that the luminosity of the combustion zone can vanish without combustion having been completely terminated. 

Show that the Eddington limiting luminosity, at which the gradient of radiation pressure balances gravity near the surface, is given by... 

When large spherical AP particles dg = 3 mm) are added, large flamelets are formed in the dark zone.Pl Close inspection of the AP particles at the burning surface reveals that a transparent bluish flame of low luminosity is formed above each AP particle. These are ammonia/perchloric acid flames, the products of which are oxidizer-rich, as are also observed for AP composite propellants at low pressures, as shown in Fig. 7.5. The bluish flame is generated a short distance from the AP particle and has a temperature of up to 1300 K. Surrounding the bluish flame, a yellowish luminous flame stream is formed. This yellowish flame is produced by in-terdiffusion of the gaseous decomposition products of the AP and the double-base matrix. Since the decomposition gas of the base matrix is fuel-rich and the temperature in the dark zone is about 1500 K, the interdiffusion of the products of the AP and the matrix shifts the relative amounts towards the stoichiometric ratio, resulting in increased reaction rate and flame temperature. The flame structure of an AP-CMDB propellant is illustrated in Fig. 8.1. 

Similar tests were conducted for Tetryl of loading d 1.60 and for TNT of d 1.55. Their luminosity curves for deton in air at atm pressure are given below. The left curves were taken using optical filters with transmission maxima at A=6870A, while the right ones used A= 4510 (Ref 5, Progr-Rept, Apr-June 1949)... 

Poulter on luminosity) 305-06(Detn of temp by radiation and spectra methods) 384 (Discussion on work done at PicArsn on radiation of pyrotechnic compns) 386 (Effect of radiation from a shock wave in an atmosphere at ordinary pressure is negligible in comparison to an endothermic reaction capable of absorbing thousands of kcal per kg of air at 10000°K) 396 (Discussion on energy loss by radiation from the body of the gas mainly in the form "Bremsstrahlung produced when electrons are deflected by ions) 398, 400, 401 403 (More discussion on radiation) 14) Cook (1958), 97, 150-53, 155 158 15) M.A. Cook et al,... 

Mason et al (Ref 22) determined pressure of deton for PETN Tetryl charges, which were used for luminosity tests. The investigation was conducted by recording the change of electrical resistance of... 

Bundy et al (Ref 13) measured the velocity and pressure of gases in a rocket flame by determining the small shift in wavelengths of the flame luminosity with a Fabry-Perot interferometer... 

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