Burning time temperature coefficient

It is now possible to calculate the burning rate of a droplet under the quasisteady conditions outlined and to estimate, as well, the flame temperature and position however, the only means to estimate the burning time of an actual droplet is to calculate the evaporation coefficient for burning, f3. From the mass burning results obtained, f3 may be readily determined. For a liquid droplet, the relation... 

The properties of this proplnt are it remains rubberlike at -40°F and does not flow at+140°F its specific impulse is 170sec at lOOOpsi optimum expansion density l,81g/cm3 an exponent of 0.70 in the burning law burning rate 0.72 in/sec at lOOOpsi 70°F, and a restriction ratio of 182 under the same conditions. The temperature coefficient of pressure, thrust, burning time at constant restriction ratio is 0.6% per °C (Ref 1, pp 101 -02)... 

Temperature coefficient— The relative change of Some measurable quantity (e.g. burning time per unit length) with change of temperature, mostly expressed as mean change per degree in percent of mean temperature within a certain range. 

Curve 2 applies to objects having a low heat conductivity coefficient, e.g., wood. In this instance, equilibrium temperatures are reached within a shorter time as compared with metal objects. Dehydration of wood takes place at 500°F, decomposition at 700°F and ignition probably at 800°F, corresponding to 1,300, 3,000 and 4,000 Btu/hr. sq. ft., respectively. This means that wooden structures and vegetation in an area with heat intensities of 3,000-4,000 Btu/hr sq. ft. and higher may catch fire and burn. Paint on equipment may also be damaged. Therefore, it is recommended that equipment located in this area be protected by heat shielding or water sprays if the installation of a stack of sufficient he ht to reduce heat radiation is impracticable. 

The complete description of a flame requires the specification of the pressure, the mass flow rate or burning velocity, the initial gas composition, and the appropriate transport coefficients and thermodynamic data. The remaining information is contained in a set of one-dimensional profiles of composition, temperature, and gas velocity as a function of distance (Fig. 2). Other independent variables than distance could have been used, e.g., temperature or time, but distance is common in experimental studies. Not all of these profiles are independent since there are a number of relations between the variables such as the equation of state, conservation of mass, etc. As an example, gas velocity can be obtained both by direct measurement and from temperature measurements using geometrical and continuity considerations. In the example given the indirect determinations of velocity are the more reliable and were used in the analysis. It is general practice to measure as many variables as convenient because the redundant profiles provide a check on the reliability of the measurements. 

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