Characteristics of Plasma Flame and their Applications (1)

Electromotive force of gas flame

Abstract

In a combustion gas flame, the electron concentration is larger than that calculated from gas temperature and ionization potential assuming a thermodynamic equilibrium. This difference is attributed to the combustion reaction in a flame, i.e., a combustion gas flame shows more remarkable electrical properties than an incombustible hot gas of the same temperature.
A voltage generation effect such as the Klein Effect of a combustion flame may be a typical example of the electrical properties.
In this paper, description is made of the effect of potential difference between nozzle and metal plate, induced by a combustion gas flame of a mixture of C₂H₂ and O₂ which is blown vertically on the plate.
First, the volt-ampere (V-I) characteristics due to the effect in a steady state are investigated.
These V-I characteristics are affected by the temperature of the metal plate, the distance between nozzle and plate and the mixing ratio of C₂H₂ and O₂.
No-load voltage, short-circuit current are in the order of one volt and of several micro amperes respectively under the condition of this experiment.
Second, in a transiant state including the case of gas cutting, the voltages caused by this effect are measured.
The theory of plasma sheath potential is applied to the analysis of the voltage generation. And discussions are made on the influences of the electron concentration in the flame, and of the temperature and the thermionic emission of the surface at the each plate on this effect.
Experimental results fairly agree with theoretical analysis.