Gaseous Combustion at High Pressure

Abstract

AT the meeting of the Royal Society on November 10 when the Duke of York was admitted to the fellowship of the Society, Prof. W. A. Bone gave an account of Parts 14, 15 and 16 of his researches on gaseous combustion at high pressure. These record an exploration of the phenomena of explosion of hydrogen-air and carbon monoxide—air mixtures into regions of pressure much higher than those hitherto examined and the apparatus specially designed for the purpose was described. Hydrogen—air mixtures explode quite normally with initial pressures up to 500 atmospheres but at 750 atmospheres detonation occurs with violence sufficient to damage the apparatus. Carbon monoxide—air mixtures have been successfully exploded at initial pressures up to 1,000 atmospheres. As previously observed, the nitrogen is activated, absorbing during the early stages energy which is released during the later stages so as to retard the cooling of the products. This activated nitrogen reacts with excess oxygen, if present at the high temperature of explosion, giving oxides of nitrogen, the formation of which is favoured by increase of pressure. Nitric oxide dissociates readily during the process of cooling, so experiments were made in which the cooling is accelerated by causing the gas to expand suddenly at a predetermined instant after firing. Exploding mixtures of (2CO + 3O2 + 2N2) at an initial pressure of 70 atmospheres, the yield of nitric oxide is 5.4 per cent, and results at 88 atmospheres indicate a prdbable maximum of about six per cent. Such yields exceed those previously recorded but are probably insufficient to serve as a basis for the commercial fixation of nitrogen by explosive combustion. Experiments were shown to demonstrate how a rise of pressure increases the luminosity of carbon monoxide—air flames and leads to the formation of oxides of nitrogen.