Thermal Explosion of Oxyhydrogen Gas Initiated by the Wall of a Quartz Reactor

Abstract

A criterion is proposed for ignition which begins on the combustion-chamber wall heated by the heterogeneous oxidation of hydrogen. Surface heating resulting in the formation of a chain-thermal avalanche and a hot flame front is calculated in accordance with Semenov's postulate of low-temperature gas ignition on a surface. The surface self-heating (firing) occurs in the self-acceleration mode according to the Arrhenius law due to the burnup of substances that block the centers of heterogeneous catalysis. The criterion for ignition initiated by a heterogeneous reaction, in contrast to criteria for a homogeneous thermal explosion in reactors with an inert wall, was developed to calculate gas ignition in reactors with a catalytically active wall.

Degenerate explosion of oxyhydrogen gas at the third ignition limit initiated by the products of a heterogeneous reaction on an inactive catalyst (Quartz)

“…The increase in p 3 was accompanied by a severalfold decrease in the reaction rate below the limit. Thus, we confirmed the conclusion [2,10] that the gas pressure at the third limit depends on the type and condition of the surface of the reactor.…”

“…The upper limit of pre-explosion heating of oxyhydrogen gas at the third ignition limit was determined in [10] on the basis of [12]. Self-heating sufficient to increase the pressure by 2.5 torr and enter the ignition region ( Fig.…”

“…The theory of Semenov [1,2] and Hinshelwood [3] is sufficient for a quantitative interpretation of the wellknown facts of combustion and explosion of gases and for a qualitative explanation of the gas-surface interaction [1][2][3][4][5][6][7][8][9][10][11]. Semenov [1,2] introduced the provision of two types of explosion which differ in the initial stage of self-acceleration of the reaction by chain branching (chain explosion) or by self-heating without branched chains (thermal explosion).…”

“…Ignition of oxyhydrogen gas by a wall of the reactor was not considered in [3,[5][6][7]. In [8][9][10], the authors, analyzing [5,11,12], made a conclusion on the initiation of an explosion at the third limit by the reactor wall producing hydrogen peroxide. Semenov [2] introduced the concept of a degenerate explosion in which an intermediate product, e.g., peroxide is exploded, and not the original substance.…”

Light-emitting pickles

“…In addition we think it seems plausible that when a gas bubble with suitable oxy-hydrogen mixture gets into contact with the hot electrode, the hydrogen starts to ignite. As a matter of fact, it is well known that hot surfaces can initiate hydrogen combustion already at around 600 °C [10]. (d) This exothermic combustion reaction lasts at most a few ms [7].…”