Gas detonation is known to be a good means to get significant amount of energy during a very short period of time. However, detonation combustion is extremely difficult to control, and this fact limits perspectives of this technique as an industrial technology. A group of Russian scientists has a solution for this problem – researchers suggest treating gaseous mixtures, in which detonation combustion takes place, with acoustic fields.

A gaseous mixture can burn in two ways; they are called deflagration and detonation. These two ways differ in flame propagation velocity. In case of detonation combustion, flame travels in mixture much faster, than during deflagration, reaching speeds near to sound velocity. Regime of detonation combustion allows most effective way of spending energy, coming from chemical fuel. Rapid energy production allows building facilities with high power capacity. Detonation facilities are used for production of various coatings, process of forming, and processing of metal parts, as well as for drilling wells and rock fragmentation. However, the process of detonation is a difficult thing to control, and scientists from all over the world are searching for a cheap and safe technique for controlling a process of gaseous mixture combustion.

 

 

A group of Russian scientists, employed at Joint Institute of High Temperatures (Russian academy of sciences, Moscow), headed by Victor Golub, suggests treating gaseous mixtures, in which detonation combustion takes place, with acoustic fields. The whole work is described in the Thermal physics of high temperature scientific magazine. You can find this magazine in English under the name of High temperature, distributed in Europe and overseas by Springer publishing house.

The experiment, conducted by Russian physicists, has involved studying both closed and half-opened pipes, filled with various gaseous mixtures (mixture of oxygen and hydrogen, for instance). External acoustic fields of various frequencies were applied, and their effect on combustion process, as well as possible beginning and end of combustion processes were analyzed. Moreover, researchers have analyzed how sounds, generated by flame itself, have affected combustion development.

Experimental studies have showed that acoustic field affected combustion process during all stages of the process. The effect got less pronounced, when combustion energy increased. During advanced stages of flame development acoustic waves could have induced detonation, and under certain parameters of frequency and intensity – could have prevented detonation from start. Therefore, experiments allowed researchers to understand how combustion regime could be controlled by means of an external acoustic field.

Results of the experiment, performed by the think-tank from Moscow, can further be used for creating special conditions for detonation facilities with simple and accurate control of combustion processes, taking place in combustion chambers.