Explosions, of hydrogen

Figure 12. Coulomb explosion of hydrogen iodide clusters. Note the formation of l+ a small signal probably attributable to l+17 is seen in some experiments. Taken with permission from ref. 92.

Personnel present during leaks, fires, or explosions of hydrogen mixtures with air can incur several types of injury. Asphyxiation may occur when entering a region where hydrogen or another nontoxic gas has displaced the air, lowering the oxygen concentration below 19.5% by volume. 

Rubidium (Rb) is a soft, silvery metal that is highly reactive—that means it reacts easily with many elements. How reactive It will burst into violent flames when exposed to water (burning is a reaction), creating an explosion of hydrogen gas. 

Sadovnikov [6] measured the change in pressure in explosions of hydrogen mixtures at p0 — 760 mm in a cylinder of 8 liters volume. His data on the cooling of the explosion products for different hydrogen mixtures all fit very well into an empirical formula containing the same constant for all mixtures ... 

The yield of nitric oxide in explosions of hydrogen mixtures at initial atmospheric pressure has been measured. The influence of the pressure in the range from 200 to 760 is in agreement with the theory. 

Because hydrogen properties and the imminent danger of explosions of hydrogen-oxygen mixtures, experiments on hydrogen should be demonstrated with care. 

I 1.2.3. Possibility of Plasma-Stimulated Ignition Below the Auto-Ignitlon Limit Conventional Kinetic Mechanisms of Explosion of Hydrogen and Hydrocarbons... 

T. I. Kunin and V. I. Serdyukov, Limits and Temperatures of Explosion of Hydrogen-Chlorine Mixtures in Hydrogen Chloride, J. Gen. Chem., USSR, Vol. 16, 1946, pp. 1421-1430. 

Two facts established by these experiments impressed on me the conviction that Berthelot might have found the true theory of explosions first the close coincidence between the rates of explosion of hydrogen (both with oxygen and nitrous oxide) and the calculated mean velocities of the products of combustion and, secondly, the great discordance between the found and calculated rates for carbonic oxide with both oxygen and nitrous oxide, for I had previously discovered that pure carbon monoxide cannot be exploded either with pure oxygen or pure nitrous oxide/... 

Will react immediately with saliva to cause serious bums and possible local combustion and even explosion of hydrogen in the mouth or esophagus. 

An example of a reaction kinetic model that exhibits all the laws described above is the adiabatic explosion of hydrogen-air mixtures (Zsely et al. 2003). Figures 8.1, 8.2 and 8.3 are related to the adiabatic explosion of stoichiometric hydrogen-air mixtures with an initial temperature of To = 800 K and a constant pressure of p = 1 atm. 

Fig. 8.2 An example of a scaling law in a model of the adiabatic explosion of hydrogen-air mixtures. Figure (a) shows the ratios of sensitivity functions belonging to the concentration of OH and temperature as a function of temperature. All ratios coincide therefore, local similarity is valid. Figure (b) shows the ratio of the production rate of OH and the time derivative of temperature, also as a function of temperature. The two curves coincide therefore, the scaling relation is also valid [see Eq. (8.3)]. Adapted with permission from Zsely et al. (2003). Copyright (2003) American Chemical Society...

Zador et al. (2004) investigated the local similarity of the sensitivity functions in a model of the adiabatic explosion of hydrogen-air mixtures at several equivalence ratios. The correlation of the sensitivity vector of H2O with all other sensitivity vectors [belonging to temperature (T) and the concentrations of species H, O2, H2O2, H, O, OH, HO2 and N2] was studied. The results, presented in Fig. 8.5, show the almost perfect local similarity of the sensitivity functions. 

The sensitivity functions were sorted in the following way. First, each function was divided by its maximum with the result that similar functions almost coincided. Figure 8.8 shows such normalised sensitivity functions for the species Cln2. It is clear that most of the functions follow either the shape indicated by the solid line ( shape A ) or that indicated by the dotted line ( shape B ). For the model simulating the explosion of hydrogen-air mixtures, all sensitivity functions were... 

Pressure and impulse in the pressure wave determine the danger level resulting from an explosion of hydrogenous combustible mixtures. The main measurable blast wave parameters are presented in the diagram (Fig. 10.1). The blast wave pressure in a gas explosion is a function of the energy release rate and it reaches a maximum at the detonation mode of combustion [1 ]. 

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