Temperature sensitivity of pressur

A change of burning rate resulting from a change of initial propellant temperature changes the equilibrium pressure, p in a rocket motor. Thus, one needs to introduce the temperature sensitivity of pressure in the combustion chamber, itj , which is defined similarly to o ... 

The chamber pressure of the motor also changes due to the change in initial temperature of propellant for a fixed nozzle. This coefficient (temperature sensitivity of pressure at constant k) is expressed as (Equation 4.13) ... 

Temperature The temperature of the extraction should be chosen for the best balance of solubility, solvent-vapor pressure, solute diffusivity, solvent selectivity, and sensitivity of product. In some cases, temperature sensitivity of materials of construction to corrosion or erosion attack may be significant. 

The burning rate of GAP copolymer increases linearly with increasing pressure in an In rversus Inp plot, as shown in Fig. 5.17. The pressure exponent of burning rateat a constant initial temperature, as defined in Eq. (3.71), is 0.44. The temperature sensitivity of burning rate at constant pressure, as defined in Eq. (3.73), is 0.010 K"h... 

Though both propellants contain equal amounts of NC and NG, the burning rate of NC-NG-GAP is approximately 70% higher than that of NC-NG-DEP at Tq = 293 K. The pressure exponent of burning rate remains relatively unchanged at = 0.7 by the replacement of DEP with GAP. However, the temperature sensitivity of burning rate defined in Eq. (3.73) is increased significantly from 0.0038 K" to 0.0083 K- ... 

Fig. 7.37 Pressure exponent and temperature sensitivity of an HMX composite propeiiant as a function of...

When these oxidizer particles are mixed with a binder such as HTPB, a nitropoly-mer, or GAP, the burning rate decreases with increasing mass fraction of ADN or HNF particles.[3+l Though the temperature sensitivity of an ADN composite propellant is significantly high in the low-pressure region, 0.005 at 1 MPa, it decreases... 

Fig. 8.17 Temperature sensitivity of HMX-CMDB propellants as a function of pressure.

As shown in Fig. 15.5, when a pyrolant of high pressure exponent is used, the variable flow range is increased. However, it is evident from Fig. 14.6 that the pressure exponent is required to be n < 1 for stable burning. It must also be noted that the temperature sensitivity of the pressure in the gas generator becomes high when a pyrolant of high pressure exponent is used. 

The burning rate of propellants is one of the important parameters for the design of rocket motors. The burning rate is obtained as a function of pressure and of initial temperature, from which pressure exponent of burning rate and temperature sensitivity of burning rate are deduced. 

The temperature profile in the combustion wave of a double-base propellant is altered when the initial propellant temperature Tq is increased to Tq -i- ATq, as shown in Fig. 6.15. The burning surface temperature % is increased to + AT, and the temperatures of the succeeding gas-phase zones are likewise increased, that of the dark zone from Tg to Tg-r ATg, and the final flame temperature from Tf to Tf-tATf. If the burning pressure is low, below about 1 MPa, no luminous flame is formed above the dark zone. The final flame temperature is Tg at low pressures. The burning rate is determined by the heat flux transferred back from the fizz zone to the burning surface and the heat flux produced at the burning surface. The analysis of the temperature sensitivity of double-base propellants described in Section 3.5.4 appUes here. 

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