Effect of concentrations of reacting substances on the stability of the flow through a chemically active skeleton with release of a gas phase

In laboratory conditions the flow of an acid solution through a chemically active porous medium is studied with account taken of the occurrence of a chemical reaction with the release of a gas phase. It is known that this process can be unstable, viz. pressure fluctuations can be observed in the reaction area. The experimental work is carried out in a flat cell filled with a mixture of sodium bicarbonate and glass beads. Mineral oil is used as a highly viscous fraction, a solution of citric acid simulates a displacing fraction. As a result of the experiments, it is found that for the occurrence of a periodic process some critical concentrations of a reducing agent and an oxidizing agent are needed, and with a deficiency of at least one of them the periodic process does not occur.