Calorimetric value, propellants

The heat given out in the combustion of propellants is readily measured by exploding them in special calorimetric bombs built to withstand the high pressures produced. The result thus obtained, however, does not necessarily give exactly the heat available under practical circumstances, as in the calorimetric bomb the products are cooled and can undergo reactions which have different equilibria at high and low temperatures. It is, therefore, usual for design purposes to obtain the calorimetric value of a propellant also by calculation. 

Heats of combstn of 32 expls) PicArsn Translation No 23(1959) by G. Loehr 35a) P. Tavernier, MP 37, 225-68(1955) (Temperature of explosion, calorimetric value, force constant of propellants and coefficient of isentropic expansion in the gun barrel) [Transl issued by Tech Info Library Services, Ministry of Supply (GtBrit), Feb 1959 (TlL/T.4837)] 36) C.G. Dunkle s Lecture at Picatinny Arsenal, delivered on Dec 13, 1955, entitled "Introduction to Theory of Detonation of Explosives , pp 10-11 (Heats of deton expln) 37) G.R. Handrick,... 

The data reported in the literature suggests that the replacement of DEP by Bu-NENA in the Dense NC/NG+ DEP/AP/AI/RDX-based composite modified double-base (CMDB) propellants results in increase in the burn rate by 18-20% at 70 kg cm pressure. The calorimetric value and percentage elongation also increase significantly. Further, thermal stability and sensitivity of such propellants are comparable with DEP-based CMDB propellants [184]. Bu-NENA is also a component of low vulnerability ammunition (LOVA) propellants [185, 186]. The introduction of butyl-NENA into SB, DB and gun propellants results in improvement of their mechanical properties and energetics and reduction in their sensitivity [187]. 

Calorific Values, Calorimetric Values and Calorimetric Potentials of Nitrocelluloses and Propellants, Taylor et al (Ref 2,p 580), define the calorific value as the heat evolved (in calories per gram) when a substance is exploded in a special calorimetric bomb capable of withstanding high pressure... 

Calorimetric Value is defined by Comer(Ref 3) as the value which is obtained by measuring the heat evolved when a propellant is burned in a bomb calorimeter contg an insert atmosphere. The temps are near 300° K. This value can also be calcd as shown in Ref 3,pp 127--8 Calorimetric Potential, Apparant (Potentiel calorimetrique, apparent in Fr). Tavernier (Ref 4,p 234) defines it as the quantity of heat evolved on the decompn of a proplnt, provided it does not do any exterior work (which means under const vol) and if the gases evolved in reaction are cooled (which means that the water is liquid). This value is, accdg to Tavernier, identical with the English value called "Calorific Value . A similar value was called by DePauw (Ref 1) "die Characteristik einer Substanz ... 

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