EXPERIMENTS ON SOLID AND GASEOUS EXPLOSIVES. 



381 



0.2 



0.3 0.4 0.5 



Time in seconds. 



0.6 



0.7 



0.8 



Fig. 16. Effect of the dimensions of the enclosure on the rate of cooling of the products of 



combustion. 



A, cylindrical explosion vessel; gravimetric density 0-15; diameter 0-175; uniformly distributed. 



B, 



C, spherical 



D, 



E, cylindrical 



F, " 

 G, 



H, ,, 



0-15: 



0-1 ; 



0-1 ; 



0-1 ; 



0-1 j 



0-1 : 



0-1 : 



0-1 ; 



0-475; 



0-175; 



0-475; 



0-035; 



0-175; 



0'175; not uniformly distributed. 



475 ; uniformly distributed. 



" 475 ; not uniformly distributed. 



When considering the products of an explosion, it must be remembered that the 

 effective conductivity of the gas is further increased by its state of rapid motion. It 

 is also augmented by the large proportion of hydrogen and water vapour contained 

 therein. 



As a result the temperature of the walls of the enclosure rises rapidly as the cooling 

 of the gas proceeds, and before long the rate of cooling will depend essentially on the 

 conductivity of the walls of the enclosure and not on the properties of the gas. The 

 heat abstracted per unit time will then be simply proportional to the temperature. 



If the logarithmic decrement of the latter part of the curve is measured, it will be 

 found that the theory is confirmed in this respect by the results of the experiments. 



