A new method of determining the thermal conductivities of energetic materials by microcalorimeter

A device of measuring the thermal conductivity of pellet of propellants and explosives has been constructed. A method and a calculation formula for determining the thermal conductivity of pellet of propellants and explosives under constant radial heat flow conditions by use of Joule effect is presented. Using this device and a microcalorimeter, type RD496-II, and two standard samples with known thermal conductivity, two instrument constant have been determined and the thermal conductivities of seven materials: plexiglass, teflon, DB propellant DB-2 (nitrocellulose(NC)/nitroglycerine(NG)/dinitrotoluene/dimethyl centralite/vaseline/PbO/CaCO₃, 59.6/25/8.8/3/1.2/1.2/1.2), DB propellant SQ(NC/NG/diethyl phthalate(DEP)/binder, 59/29/7/5), DB propellant RHN-149 (NC/NG/triacetin (TA)/binder-I, 52/25/8/15), DB propellant RHN-190 (NC/NG/TA/ binder-II, 52/26/7/15), 2, 4, 6-trinitrotoluene (TNT) at 298 K are measured. The results show that (1) the reproducibility of measurement for the heat (q) retained in investigated system after cutting the Joule current and the amount of heat flux through the wall of the investigated cylinder (Q _s) are less than 0.50% and within 0.10%, respectively; (2) the standard deviation of the thermal conductivity determined by using this method is less than 1.0%; (3) the values ofq, Q _s and internal radius of the cylinder are three principal factors affecting the magnitude of the thermal conductivity of these materials.