Experimental Determination of Non-ignition Diameter for Various Ignition Positions

Abstract

When a nozzle diameter is greater than the quenching diameter, the flame from an explosion inside a chamber can pass through the nozzle, but it will not always ignite the outside combustible mixture. There is a non-ignition diameter, greater than the quenching diameter, below which ignition will not occur and above which it will. The present paper presents experimental determinations of non-ignition nozzle diameters for different values of several parameters (ignition position, mixture concentration and chamber volume). The non-ignition diameter is affected by the ignition position, the mixture concentration and the primary combustion chamber volume. As the ignition position moves to the far end of the nozzle, the non-ignition diameter increases gradually, and the largest non-ignition diameter exists at the ignition position 3, having the highest introduced pressure. For any ignition position, the minimum non-ignition diameter is found to occur near the stoichiometric mixture. The non-ignition diameter is approximately proportional to the ejected velocity.